INFORMATION TO USERS

This manuscript has been reproduced frwn the rnkfdilrn master. UMI films

the text directly from the Winal or copy submitted. Thus, some thesis and

dissertation copies are in W e r face, while others may be from any type of

computer printer.

The quality of this mproduction is dependent upon the quality of the

copy submitted. Broken or indistinct print, dored or poor quality illustrations

and photographs, print bkedthrwgh, substandard margins, and improper

alignment can adversely affec2 reproduction.

In the unlikely event that the author did not send UMI a complete manuscript

and there are missing pages, these will be noted. Also, if unauthorized

copyright material had to be removed, a note will indicate the deletion.

Oversize materials (e.g., maps, drawings, charts) are reproduced by

sectioning the original, beginning at the upper left-hand corner and continuing

from left to right in equal sections with small overlaps.

Photographs included in the original manuscript have been reproduced

xerographically in this copy. Higher quality 6' x 9" Mack and Mite

photographic prints are available for any photographs or illustrations appearing

in this copy for an additional charge. Contact UMI directly to order-

Bell & Howell Information and Learning 300 North Zeeb Road, Ann Arbor, MI 48106-1346 USA

800.521-0800

LABORATORY INVESTIGATIONS

IN THE PSYCHOPHYSIOLOGICAZI DETECTION OF DECEPTION

by

ISATO E'URUMITSU

A thesis submitted i n conformity with t h e requirements fo r the Degree of Doctor of Philosophy, Graduate Department of Psychology, i n t h e University of Toronto.

O Isato Furumitsu 1999

National Library BibliotMque nationale of Canada du Canada

Acquisitions and Acquisitions et Bibliographic Services services bibliographiques

395 Wellington Street 395. rue Wellingtm OtcawaON K l A W OrtawaON KlAON4 Canada Canada

The author has granted a non- exclusive licence allowing the National Library of Canada to reproduce, loan, distribute or sell copies of this thesis in microform, paper or electronic formats.

L'auteur a accorde m e licence non exclusive pennettant a la Bibliotheque nationale du Canada de reproduire, prster, dismbuer ou vendre des copies de cette these sous la fome de microfiche/fih, de reproduction sur papier ou sur format electronique.

The author retains ownership of the L'auteur conserve la propriete du copyright in this thesis. Neither the droit d'auteur qui protege cette these. thesis nor substantial extracts fiom it Ni la these ni des extraits substantiels may be printed or othewise de celle-ci ne doivent &e imprimis reproduced without the author's ou autrement reproduits sans son permission. autorisation.

LABORATORY INVESTIGATIONS I N THE PSYCHOPHYSIOLOGICAL

DETECTION OF DECEPTION

Doctor of Philosophy, 1999

Isato Furumitsu

Department of Psychology, Universi ty of Toronto

Abs t rac t

I n t h e psychophysiological d e t e c t i o n of deception, t h e Guilty

Knowledge T e s t (GKT) is a far more ob jec t i ve way of

d i s t i ngu i sh ing between g u i l t y and innocent suspects , but is

less i n use in f i e l d p r a c t i c e than t h e con t rove r s i a l Control

Quest ion T e s t (CQT). I n an e f f o r t t o con t r i bu t e towards f u l l

understanding and s tandard iza t ion of t h e GKT, two experiments

were carried o u t t o examine accuracy of t h e GKT in a

labora to ry s i t u a t i o n where p a r t i c i p a n t s role-played a crime

scenario. Experiment I was a conceptual r e p l i c a t i o n of a

study by Nakayama e t a l . (1988), who repor ted t h a t de t ec t i on

was s u p e r i o r wi th sk in conductance response (SCR) as

dependent measure, when p a r t i c i p a n t s were required t o de lay

t h e i r answers f o r 8 seconds r a t h e r than answer immediately as

i s customary. I n t h e experiment, t h e GKT ques t ions were

presented i n a v i s u a l mode on computer screen, a procedure

t h a t is more s tandardized t han t h e usua l procedure where a

human examiner asks t h e ques t ions . The r e s u l t s ind ica ted

t h a t both SCR and r eac t i on t i m e (RT) d iscr iminated between

r e l e v a n t ( l a r g e r SCR and s h o r t e r RT) and n e u t r a l i tems, bu t

wi th no d i f f e r e n c e between immsdiate- and delayed-answer

condi t ions . I n Experiment 11, aud i to ry computer-synthesized

vo ice p r e sen t a t i on of t h e GKT was employed and t h e

p a r t i c i p a n t ' s emotional r e a c t i o n t o t h e re levan t items was

manipulated. To examine an o r i e n t a t i o n and hab i tua t i on

account of t h e GKT e f f e c t , a simple o r i en t i ng response (OR)

paradigm for obta in ing p a r t i c i p a n t s ' SCRs t o repeated s t i m u l i

was carried o u t p r i o r t o t h e de t ec t i on phase. The emotional-

r e a c t i o n manipulation d i d not affect de tec t ion , which,

however, w a s aga in s i g n i f i c a n t both f o r t h e SCR ( l a r g e r ) and

RT ( s h o r t e r ) . One of t h e OR effects, r e i n s t a t e d OR, showed a

small b u t s i g n i f i c a n t c o r r e l a t i o n with t h e GKT e f f e c t . Taken

toge ther , the present r e s u l t s sugges t t h a t GKT i s e f f e c t i v e

regardless of response manner, and i ts e f fec t iveness can be

p a r t l y a t t r i b u t e d t o an a t t e n t i o n a l , o r i en t i ng process i n t h e

p a r t i c i p a n t , r a t h e r than t o emotional f ac to r s . ~ d d i t i o n a l l y ,

computerized p resen ta t ion xuay be use fu l f o r i nc r ea s ing

o b j e c t i v i t y i n t h e de tec t ion of deception through t h e GKT.

Non-physiological dependent variables l i k e r eac t i on time may

a l s o provide add i t i ona l information f o r de tec t ion of

deception.

iii

F i r s t and foremost I want t o thank my superviaor,

John J. Furedy, for h i s valuable encouragement and advice at

every s t a g e of t h i s work. I also want t o thank t h e o t h e r

members of my committee, Kenneth L. Dion and Ronald J.

Heslegrave, f o r t h e i r advice and i l lumina t ing d i s cus s ions at

va r ious s t ages of the project.

I thank Y o Miyata and S h o j i Kakigi i n Japan, who j o i n t l y

recommended m t o s tudy abroad and o r i g i n a l l y in t roduced m e

to John J. Furedy. I extend my thanks t o Magniis Kr is t jdnsson

and h i s w i f e , ~ u b r t i n Amarsdbttir, f o r their co-operation and

f r i e n d s h i p throughout g radua te school . I also express my

app rec i a t i on t o Makoto Nakayama and S h i n j i Hira, t w o

scholarly active Japanese police polygraphers, for t h e i r

h e l p f u l comments on an earlier ve r s ion of t h i s t h e s i s .

However, my wannest thanks go to my wife, Shoko. I

thank her f o r h e r pa t i ence , understanding, and unre l en t ing

suppor t .

TABLE OF CONTENTS

INTRODUCTION ........................................ m.ml

.......... Psychophysiological S tud ies of Deception 1

Brief His tory of Detect ing Deception .............. 3 General Descript ion of t h e Control Quest ion T e s t

............................................. (CQT) 6

..................... Problems Inherent i n t h e CQT 11

.... Ambiguous meaning of " con t ro lw ques t ions 11

Lack of s t andard iza t ion of t h e method ....... 13 ..... Poor psychophysiological q u a n t i f i c a t i o n 15

......... Contamination problems i n diagnoses 17

F a i l u r e t o s epa ra t e d e t e c t i o n of deception .................. from confession inducement 19

General de sc r ip t i on of t h e Gui l ty Knowledge T e s t

(GKT) .......................................... ..20 ......... The GKT as A S c i e n t i f i c Detect ing Method 22

S c i e n t i f i c c o n t r o l ques t ions ................ 22 E a s e of s t andard iza t ion ................... ..23 L e s s contamination in t h e procedure ........ -23

SCOPE OF THE STUDY .............ma.........m......... ..26 EXPERIMENT I ........................................ ..28

Design of Experiment I .................a.e....... 31 Method ........................................... 3 3

P a r t i c i p a n t s .............................. ..33 Apparatus ..............a.m.....m............ 33 Procedure ................................... 34

.......................... Dependent Measures 4 1

Results ........ma.....................m.......... 44

Skin Conductance Responses during t h e Matching T r i a l ............................a. 44

Skin Conductance Responses during t h e Detect ion Pe r iod ........................... .46 C l a s s i f i c a t i o n Index ........................ 50

Reaction Time t o t h e Relevant and Neutral Quest ion .................................... 51

Discussion ....................................... 53

EXPERIMENT I1 ....................................... 0.59

Design of Experiment 11 .......................... 65

Method ......................m.................... 66

................................ Part ic ipants 66

Apparatus ................................... 66

Procedure ................................... 68

Dependent Measures .......................... 73

Results .......ma.......m......................... 75

Skin Conductance Responses i n t h e

Preliminary Novelty Paradigm (PNP) .......... 75

Effec ts of t h e Alarm Manipulation on t h e

.......................... Experimental Group 76

Skin Conductance Responses during t h e Detection Period ..a.m.....a............. 79

Reaction Time t o t h e Relevant and ....................... the Neut ra l Ques t ions 85

Relationship between t h e Novelty Effects

and t h e GKT E f f e c t .....m.....m.............. 89

C l a s s i f i c a t i o n Index ........................ 91

Discussion ..................................... ..92

...................... GENERAL SUMMARY AND DISCUSSION .lo0

REFERENCES ...................m....................... 113

APPENDIX A ........................................... 124

APPENDIX B ........................................... 126

INTRODUCTION

Studies of Dec-

Human s o c i e t y has always been interested in d e t e c t i n g

deception, e s p e c i a l l y when t h e decept ion is p rac t i s ed t o

cover up g u i l t . A c e n t r a l concern o f t h e p resen t t h e s i s is

t h e psychophysiological d e t e c t i o n of deception, a l s o

popular ly known as t h e l ie d e t e c t i o n o r polygraph test, i n

which, by d e f i n i t i o n , only unobt rus ive ly measured

phys io log ica l responses are examined f o r de t ec t i ng deception.

The name "lie de tec t ion" or "de t ec t i on of deception" sugges ts

t h a t t h e s e techniques d i r e c t l y deal wi th deception o r

i d e n t i f y " s p e c i f i c l ie responses" i n humans, but , as w e s h a l l

later see i n d e t a i l , accura te d e t e c t i o n of g u i l t could, i n

p r i n c i p l e , be achieved without t h e r e being any s p e c i f i c l ie

responses.

Another problem i n t h e psychophysiological approach to

decept ion is t o s p e c i f i c a l l y d i f f e r e n t i a t e between decept ion

and t r u t h f u l n e s s as psychological processes, which would be

r e f l e c t e d by physio logica l i nd i ce s . To demonstrate decept ion

as a psychophysiologica1 phenomenon, a comparison of

phys io log ica l responses should be made between two

cond i t ions , experimental and c o n t r o l condi t ions , which d i f f e r

only wi th r e s p e c t t o decept ion (Furedy, Davis, & Gurevich,

1988). Furedy and h i s col leagues (Furedy e t al . , 1988;

Furedy, G i g l i o t t i , & Ben-Shakhar, 1994; Furedy, Posner, &

Vincent, 1991; Vincent & Furedy, 1992) have pursued t h i s area

of research with t h e i r Differentiation-of-Deception Paradigm

(DDP), in which research pa r t i c ipan t s are presented with a

series of questions, usually concerning t h e i r own

autobiographies, and requested t o produce deceptive answers

t o half of them, and t r u e answers t o t h e o ther ha l f . Given

t h a t a l l t h e questions are equivalent i n t h e i r s ignif icance

to t h e pa r t i c ipan t s and i n t h e i r frequencies i n t h e sequence,

only t h e d i f fe rence between t h e expr inmnta l and con t ro l

conditions, it is argued, cons t i tu t e s deception i t s e l f .

However, t h i s i s not t h e case i n any applied

psychophysiological detection techniques. The DDP s tud ies

w i t h electrodermal response a s a dependent var iab le have

yielded the expected increase i n responding t o deceptive

question r e l a t i v e t o honest questions (Furedy et al., 1988),

and have indica ted t h a t t h i s e f f e c t is probably not due to

cognitive f a c t o r s such as d i f f e r e n t i a l r e t r i e v a l d i f f i c u l t y ,

and t h a t it i s a l s o r e l a t i v e l y unaffected by motivational

fac tors (Vincent & Furedy, 1992) . However, a s argued by

Furedy et a l . (1988), t h e DDP does not have any direct

applied s ignif icance. A related point i s t h a t it is

important t o d is t inguish between t h e applied aim of detect ing

deception and t h e s c i e n t i f i c aim of d i f f e ren t i a t ing deception

from other related but d i f f e r e n t psychological processes

(Ben-Shakhar & Furedy, 1990) . As s t a t e d above, t h e present

thesis is concerned with t h e former, detection-oriented type

of research. My c e n t r a l purpose i s to contr ibute towards

understanding and standardization of a psychophysiological

d e t e c t i o n of d e c e p t i o n t h a t has a genuine s c i e n t i f i c

r a t i o n a l e ,

From a n c i e n t days to t h e Middle Ages, commonly used

methods of detecting decept ion i n c l u d e d t r i a l by combat,

t r i a l by ordeal, and phys ica l t o r t u r e (Kleinmuntz & Szucko,

1984a; T r o v i l l o , 1939) . These methods may have been t h e

p r i n c i p a l means o f so lv ing d i s p u t e s f o r many admin i s t r a to r s

i n t h o s e days , b u t they are f a r from determining, on a

s c i e n t i f i c basis, whether decept ion has in f a c t occurred.

Tor ture , i n p a r t i c u l a r , was designed t o detect g u i l t by

e l i c i t i n g a confess ion . However, t h e r e is no guarantee t h a t

such a c o n f e s s i o n is t r u e ; it might be g iven only t o s t o p t h e

i n t e r r o g a t i o n p r o c e s s and t h e t o r t u r e .

A more s u b t l e and p l a u s i b l e way t o detect decept ion is

t o observe overt behaviora l i n d i c e s o f decept ion , and t h i s

may be commonly p r a c t i c e d by o r d i n a r y people i n t h e i r d a i l y

l i f e , a l though such p r a c t i c e i s n o t t o t a l l y based on

s c i e n t i f i c knowledge. Severa l s c i e n t i f i c a t tempts have also

been made by psycho log i s t s to examine t h e behaviora l

c o r r e l a t e s of l y i n g . Indices of t h i s sort t h a t have been

i n v e s t i g a t e d i n c l u d e measures of r e a c t i o n time (e.g.,

Goldstein, 1923; Jung, 1906/1973, 1910; Marston, 1920),

i n t e r f e r e n c e w i t h motor behavior ( L u r i a , 1932; Runkel, 1936),

changes i n v o i c e q u a l i t y (Alpe r t , Kurtzberg, & Friedhof f ,

1963; Horvath, 1978) , and changes i n frequency of o t h e r

nonverbal behaviors , such a s pos tu r a l changes, eye con tac t ,

eye movements, ge s tu r e s , f a c i a l express ions , and speech

h e s i t a t i o n (e.g., Ekman, 1985; Ekman & Friesen, 1969, 1974).

However, such behav iora l ind ices are under voluntary con t ro l

t o a significant degree, which s eve re ly limits t h e i r

p o t e n t i a l use fu lness f o r de t ec t i ng decept ion (Furedy, 1986).

Indeed, De Paulo and P f e i f e r (1986) had t h e i r p a r t i c i p a n t s

t r y t o d e t e c t decept ion from ve rba l and non-verbal cues and

found t h a t very few p a r t i c i p a n t s had eve r achieved an

accuracy l e v e l g r e a t e r than 60 percen t (in t a s k s f o r which 50

percent accuracy would represen t a chance l e v e l ) , and some

even performed worse t han chance.

I n c o n t r a s t , small changes i n psychophysiological

funct ions , such as skin conductance, blood pressure,

r e s p i r a t i o n , and h e a r t rate, are usua l l y unnoticeable t o

human p a r t i c i p a n t s bu t are recordable through sur face

e lec t rodes . Th i s proper ty minimizes t h e p o t e n t i a l problems

assoc ia ted w i t h t h e p a r t i c i p a n t ' s awareness of both h i s o r

her i n t e n t i o n t o deceive and of l ea rned voluntary behaviors

taken as s i g n s of honesty, such as looking s t r a i g h t i n t o t h e

ques t i one r ' s eyes. Hence, by e l imina t ion , t h e

psychophysiological method appears t o o f f e r t h e only f e a s i b l e

way t o d e t e c t decep t ion i n human communication t o t h e e x t e n t

t h a t such d e t e c t i o n is poss ib le (Furedy, 1986).

Indeed, t h e psychophysiological de t ec t i on of deception

has been a major r e sea r ch area i n psychophysiology s i n c e t h e

e a r l y 1960s (e.g., Davis 1961; Gustafson 61 Orne, 1963, 1964;

Kugelmass, L i e b l i c h , 6 Bergman, 1967; Lykken, 1959, 1960;

Orne, Thackray, 6 Paskewitz, 1972). It has been of major

app l i ed s i g n i f i c a n c e , because testing of t h i s s o r t would

bring a p o t e n t i a l l y s e r i ous consequence i n t o t h e c r im ina l

j u s t i c e system. However, a consensus on t h e s c i e n t i f i c

v a l i d i t y of the psychophysiological d e t e c t i o n has not y e t

been e s t a b l i s h e d among psychophysiologists .

According to Trovillo (1939), basic resea rch into nuxiern

psychophysiological de t ec t i on of decep t ion can be traced t o

t h e la te n ine t een th century , when Lombroso, an I t a l i a n

c r imino log i s t , several times assisted t h e police i n

i d e n t i f y i n g criminal suspec t s through t h e use of blood

pressure , which had become p o s s i b l e w i th t h e development o f

equipment t h a t would measure psychophysiological func t ions

r e l a t i v e l y unob t rus ive ly (Furedy, 1986). Later i n t h e United

States, Hugo Miinsterberg (1908), a well-known psychologis t a t

Barvard, sugges ted t h e a p p l i c a t i o n of psychophysiological

measurement t echn iques such as blood p re s su re recording to

fo r ens i c problems. One of h i s American s tuden t s , Marston

(1927), conducted a psychophysiological d e t e c t i o n s tudy and

reported a 96% accuracy rate us ing blood pressure as t h e

single measure. Lykken (1981, 1998) credited Marston as

being t h e first t o in t roduce t h e no t i on of a " s p e c i f i c lie

response," which could be detected by a unique

psychophysiological p a t t e r n of responding, a not ion now

d i s c r e d i t e d by many "detect ing-decept ion" opponents (e.g.,

Ben-Shakhar & Furedy, 1990; Ben-Shakhar, L ieb l i ch , & Bar-

H i l l e l , 1982; Furedy, 1987; Furedy & Heslegrave, 1988, 1991;

Kleinmuntz & Szucko, 1984a; Lykken, 1978, 1979, 1981, 1984;

Saxe, Dougherty, & Cross, 1985) but not c l e a r l y s o by its

proponents (e .g- , Honts & Raskin, 1988; Podlesny & Raskin,

1977; Raskin, 1979, 1989; Raskin & Podlesny, 1979).

Subsequent t o Marston, several in te r rogat ion methods f o r

psychophysiological detect ion of deception have been

developed and are currently used i n f i e l d prac t ice (Saxe,

Dougherty, & Cross, 1985)-

According t o Lykken (1998), thousands of Americans are

subjected t o polygraph o r " l i e de tec tor" tests each year; and

countr ies such as Canada, Israel, Japan, South Korea, Mexico,

Pakistan, t h e Phil ippines, and Thailand use t h e polygraphic

examination i n cr iminal inves t iga t ion and secur i ty

applications. The United S ta te s , however, i s t h e l a r g e s t

consumer of psychophysiological detect ion of deception, and

t h e place where t h e most t r a d i t i o n a l and controversial

in te r rogat ion method ca l led Control Question T e s t (CQT) has

been employed.

C C t [ C W

The CQT was developed by John Reid and h i s associates i n

1947 f o r use i n criminal invest igat ions (Reid & Inbau, 1 9 7 7 ) .

Several in t e r roga t ion methods e x i s t and a r e current ly used i n

various areas. A c e n t r a l fea ture of these methods is mostly

exemplified i n t h e CQT, and i ts nature has been the t o p i c of

considerable and o f t e n v i t r i o l i c debate in t h e s c i e n t i f i c

community ( e - g o , Lykken, 1978 versus Raskin, 1978; Lykken,

1979 versus Raskin 6 Podlesny, 1979; Furedy, 1993, 1996

versus Honts, Kircher, & Raskin, 1995; Furedy & Ben-Shakhar,

1993 versus Honts, 1993). The b a s i c assumption underlying

t h e CQT is t h a t an examiner can d e t e c t deception i n an

ind iv idua l by comparing h i s or her physiological responses t o

quest ions r e l a t i n g t o t h e crime or o t h e r critical events of

interest and t o quest ions no t d i r e c t l y r e l a t i n g t o t h e crime

but s t i l l causing high a l e r t n e s s i n most examinees. On t h e

bas i s of t h i s assumption, three types of quest ions are

administered t o an examinee, whi le h i s or her

psychophysiological responses (e .g , , electrodermal response,

plethysmographic response, and r e s p i r a t i o n ) are concurrently

recorded, These three types of quest ions are re fe r red t o a s

re levan t , i r r e l e v a n t ( o r n e u t r a l ) , and "control " questions.

The r e l e v a n t quest ions r e f e r d i r e c t l y t o t h e critical

inc iden t under i nves t iga t ion ( e -g . , " D i d you s t e a l t h e money

from M r . Smith ' s drawer last Friday n i g h t ? ) , whereas t h e

i r r e l e v a n t quest ions a r e unrela ted t o t h e incident (e ,g . ,

"Were you born i n Japan?"). The c o n t r o l questions are

designed t o be unrela ted t o t h e i nc iden t under inves t iga t ion ,

but are assumed t o e l ic i t a t least a s much emotion a s t h e

r e l evan t ques t ions do f o r an innocent suspect (e -g . , "Apart

from t h e p re sen t incident , d id you eve r t ake something t h a t

d id not belong t o you?"). I f t h e psychophysiological

responses are general ly g r e a t e r t o t h e re levan t quest ions,

then t h e examinee i s considered decept ive on t h e re levan t

quest ions , and hence g u i l t y of t h e crime; i f t h e responses

are g r e a t e r t o t h e c o n t r o l ques t ions , t h e examinee is

considered t r u t h f u l on t h e r e l evan t ques t ions , and hence

innocent of t h e crime. I f t h e r e is no cons i s ten t d i f f e r e n c e

i n e i t h e r d i r e c t i o n , an inconclus ive dec i s ion is given

(Raskin, 1989). Before not ing p o s s i b l e problems with t h e

in fe rence involved in this r a t i o n a l e , t h e whole CQT procedure

should be b r i e f l y described because t h e r e are severa l other

s c i e n t i f i c problems inherent i n t h e CQT procedure o t h e r t h a n

i ts in fe rence r u l e s .

A t y p i c a l CQT procedure, as a whole, can be d iv ided i n t o

four phases, namely: a p r e t e s t in terview, administrat ion of

CQT polygraph "tests," a scor ing phase, and a p o s t t e s t

in te rv iew (Ben-Shakhar & Furedy, 1990). The f i r s t phase is a

p r e t e s t i n t e rv i ew which l a s t s 30-60 minutes. During t h e

in terview, both t h e re levan t and c o n t r o l quest ions are

formulated through a discuss ion between t h e examiner and

examinee. The r e l evan t quest ions are reformulated u n t i l t h e

examinee i n d i c a t e s t h a t he o r she f i n d s them unambiguous, and

can c l e a r l y answer "no" t o them ( L e o , i nd i ca t i ng his o r her

innocence). The c o n t r o l quest ions are reformulated u n t i l a

ve rs ion is a r r i v e d a t f o r which, i n t h e examiner's view, t h e

examinee's answer "no" is e i t h e r t o t a l l y deceptive o r at

least not con f iden t l y t r u t h f u l . I n o t h e r words, it leads t h e

examinee to b e l i e v e t h a t admissions w i l l cause t h e examiner

t o form t h e op in ion t h a t he o r she i s dishones t and is

t h e r e f o r e i n c l i n e d t o gu i l ty . Raskin (1989) summarized t h e

r e l a t i o n s h i p between t h e re levan t and c o n t r o l quest ions i n

t h e CQT as follows: Cont ro l ques t ions are designed t o g ive an innocent s u s p e c t an oppor tuni ty t o become more concerned about ques t ions o t h e r t han t h e r e l evan t ques t ions , thereby caus ing t h e innocent suspect t o react more s t rongly t o t h e c o n t r o l than t o t h e r e l evan t ques t ions . If t h e

s u b j e c t does react with g r e a t e r s t r e n g t h t o t h e c o n t r o l ques t ions , t h e r e s u l t is i n t e r p r e t e d as t r u t h f u l - On t h e o t h e r hand, s t ronger r e a c t i o n s t o t h e re levant ques t ions are i n t e rp re t ed as i n d i c a t i n g t h a t t h e

s u b j e c t was decept ive to t h e r e l e v a n t quest ions. The problem of no " spec i f i c l ie response" is circumvented by t h e procedure of drawing in f e r ences about t r u t h or decept ion by comparing t h e relative s t r e n g t h of t h i s p a r t i c u l a r s u b j e c t ' s r eac t ions t o r e l e v a n t and con t ro l ques t i ons - (pa 253)

The second phase is a "test" phase which lasts f o r about

ha l f an hour and is begun by connecting t h e physiological

recording ins t rument to t h e examinee. The test phase proper

i s o f t e n preceded by t h e card o r "stim" test which is

designed t o convince t h e examinee of t h e v a l i d i t y and

i n f a l l i b i l i t y of t h e polygraph examination as a l ie de t ec to r -

I n t h i s card test t h e examinee is asked t o choose a card f r o m

a deck- The examiner t hen calls ou t t h e names of severa l

cards to which t h e examinee is asked t o g ive negative answer-

While doing so, t h e examiner pretends t o eva lua t e t h e

polygraph recording- Af t e r t h e las t cal l is made, t he

examiner correctly informs t h e examinee which card he or s h e

chose and asserts t h a t t h e polygraph revea led t h e choice.

However, t h e deck of c a r d s is prearranged so t h a t t h e

examiner knows e x a c t l y which card has been picked by t h e

examinee.

Usually, a sequence of ques t ions c o n s i s t s of 10

q u e s t i o n s , three pairs of t h e r e l e v a n t and c o n t r o l ques t ions ,

w i t h t h e remainder being t h e i r r e l e v a n t ques t ions . The

i r r e l e v a n t q u e s t i o n serves a s an i n i t i a l b u f f e r designed t o

h a b i t u a t e t h e r e a c t i o n t h a t normally o c c u r s t o whatever t h e

q u e s t i o n is. These q u e s t i o n s are p r e s e n t e d about 30 sec

a p a r t and each r e p e t i t i o n through t h e list is called a

"test." The test is r e p e a t e d at least three times, after

t h a t t h e examiner can decide whether or n o t t o g ive one o r

t w o more.

When t h e examiner has decided t o s t o p g i v i n g t h e "test"

phase, t h e t h i r d phase i s i n i t i a t e d , During t h i s phase, t h e

examinee is left a l o n e f o r some 20 minutes , wh i l e t h e

examiner l eaves t o score t h e psychophysiological records.

C l e a r l y t h e t h i r d phase has a r o l e in t h e confession-inducing

f u n c t i o n of t h e polygraphic i n t e r r o g a t i o n , because during

t h i s phase t h e examinee has l i t t l e else t o do except worry

abou t whether he or she w i l l be judged "decep t ive" by t h e

examiner.

I f t h e examiner decides t h a t t h e examinee has been

d e c e p t i v e , t h e examiner tries, upon r e t u r n i n g , t o induce a

c o n f e s s i o n of g u i l t d u r i n g t h e " p o s t t e s t in terv iew." This

f o u r t h phase can last from 10 minutes t o s e v e r a l hours. That

i s , t h i s last phase is terminated e i t h e r by a confession or

by t h e examiner 's d e c i s i o n t h a t he o r she w i l l n o t be able to

g e t a confession.

There are several elements of t h e CQT that are of

p a r t i c u l a r concern t o i ts opponents (e.g., Ben-Shakhar, 1991;

Ben-Shakhar & Furedy, 1990; Furedy, 1985, 1987, 1989, 1991,

1993; Furedy & Heslegrave, 1988, 1991; Kleinmuntz & Szucko,

1984a; Lykken, 1979, 1981; Saxe, 1991; Saxe, Dougherty, &

Cross, 1985). They are summarized as follows: (a) t h e

ambiguous meaning o f w c o n t r o l w quest ions, (b) lack of

s t anda rd i za t i on of t h e method, (c) poor psychophysiological

q u a n t i f i c a t i o n , (d) contaminat ion problems of d i agnos i s by

factors o t h e r than psychophysiological responses, and (e)

f a i l u r e t o s epa ra t e d e t e c t i o n of deception from confession

inducement. These claims w i l l be b r i e f l y reviewed below. I# -. The first and

foremost problem inhe ren t i n t h e CQT is t h a t it employs

ques t ionab le "con t ro l " ques t ions which do no t t r u l y

c o n s t i t u t e c o n t r o l i n t h e s c i e n t i f i c sense of t h e tenn (Ben-

Shakhar & Furedy, 1990; Lykken, 1981). The normal sense of

t h e term "contro l" i n an exper imenta l /cont ro l comparison is

t h a t t h e c o n t r o l cond i t i on is i d e n t i c a l i n every r e s p e c t t o

t h e "experimental" cond i t i on , except f o r t h e critical

d i f f e r ence being s t ud i ed . I f t h e purpose of the CQT

admin i s t ra t ion is to detect decept ion and t h i s is

accomplished by comparing responses to t h e r e l e v a n t

(experimental) and "con t ro l " quest ions, then the on ly

d i f f e r ence between t h e s e two types of ques t ions should be

presence and absence, respectively, of deception. However,

t h i s is not t h e case i n t h e CQT or i n any o t h e r

psychophysiological d e t e c t i o n technique. As mentioned

earlier, t h e d i f f e r e n t i a t i o n of deception from o t h e r

psychological processes can be accomplished on ly by t h e

Differentiation-of-Deception Paradigm (Furedy et al., 1988).

Even i f t h e t a r g e t for de tec t ion is not t he process of

deception, but t h e g u i l t o f t h e examinee, t h e

re levan t /con t ro l comparison does not c o n s t i t u t e c o n t r o l in

t h e normal s c i e n t i f i c s ense of t h e term, because t h e t w o

t ypes of quest ions differ on a number of dimensions besides

t h a t of whether or not t he examinee is g u i l t y or innocent.

One such confound is a d i f f e r e n t arousal level supposedly

introduced i n t h e examinee by t h e re levan t and c o n t r o l

ques t ions . I n t h e CQT, it is r e l a t i v e l y easy to i d e n t i f y

which quest ions are t h e r e l e v a n t ones because du r ing t h e

p r e t e s t interview, t h e examinee has thoroughly l ea rned about

t h e event under i n v e s t i g a t i o n , and then only the r e l evan t

ques t ions seem t o p lace t h e examinee i n s e r i o u s jeopardy,

whether t h e examinee is innocent or gu i l t y . In such a

th r ea t en ing s i t u a t i o n , e s p e c i a l l y f o r a naive innocent

person, one might suppose t h a t everyone would respond more

s t rong ly t o t h e r e l evan t ques t ions , meaning t h a t a l l

examinees, honest or decept ive , should f a i l t h e CQT. Indeed,

reviews of t h e l i t e r a t u r e have revealed f a l s e - p o s i t i v e rates

(Lee , t h e rate of innocen t suspects classified as g u i l t y )

for t h e CQT as high as 50%, wi th a mean in t h e mid-30% range

(see Ben-Shakhar & Furedy, 1990; Kleinmuntz 6 Szucko, 1984b;

Lykken, 1974, 1979; Saxe et a l e , 1985). This no t only raises

t h e i s s u e of test v a l i d i t y bu t also t h e i s s u e of t h e e t h i c s

of t h e examiners.

I n summary, then , no c o n t r o l i n t h e n o r ~ m l , s c i e n t i f i c

sense of t h a t term is involved i n t h e CQT, hence t h e use of

t h e term in t h e CQT is misleading.

of s- of -. Because t h e

technique is r e f e r r e d t o as t h e Control Ques t ion "Tes t , " i t s

s t anda rd i za t i on ought t o be a minimum requirement.

Psychological tests are u s u a l l y s tandardized i n two important

ways (Blinkhorn, 1988). F i r s t , t h e test is t h e same for

everyone who takes it. Second, an examinee's score is

compared wi th popula t ion norms, i n order t o render t h e

r e s u l t s of t h e test i n t e r p r e t a b l e . However, n e i t h e r

c r i t e r i o n can be accomplished i n t h e CQT, because t h e

r e l e v a n t ques t ions are event- or cr ime-specif ic and, hence,

t h e y are d i f f e r e n t f r o m case t o case, Even i f t h e CQT i s

used with t h e same type of crime with t h e same t ype of

r e l e v a n t ques t ions for d i f f e r e n t suspects , t h e n t h e l ' cont r01~~

ques t ions are s t i l l d i f f e r e n t from suspect t o suspec t ,

because of t h e manner i n which t h e con t ro l ques t i ons are

formulated. Thus no s t anda rd norm can eve r be e s t ab l i shed ,

Formulating a p p r o p r i a t e l y s e n s i t i v e c o n t r o l ques t ions

seems to be extremely d i f f i c u l t , and creates an obstacle to

s t anda rd i za t i on of t h e test. The whole logic o f t h e method

depends on t h e a b i l i t y of t h e examiner t o make t h e wcon t ro lw

ques t ions l o o k mre t h r e a t e n i n g for innocent su spec t s and to

make t h e r e l e v a n t ques t i ons look more t h r ea t en ing for t h e

g u i l t y , and t h i s is carried o u t through a dynamic examiner-

examinee i n t e r a c t i o n du r ing t h e p r e t e s t interview. This

means t h a t t h e v a l i d i t y of t h e procedure w i l l be d i f f i c u l t ,

i f no t impossible, to assess even i n p r inc ip l e (Ben-Shakhar &

Furedy, 1990).

Advocates of t h e CQT have recen t ly recommended t h e use

of a purpor ted ly more s t anda rd i zed form of t h e CQT, called

t h e Directed L i e T e s t (DLT; e m g o , Honts et al. , 1995; Raskin,

1989) . I n t h e DLT, directed-lie quest ions like Wave you

e v e r told a l i e ? " or "Have you e v e r made a mistake?" are

in t roduced i n s t ead of so-called "contro lw ques t ions . To each

directed l i e quest ion, t h e examinee is reques ted t o g ive an

answer "no," and it is made clear t h a t , for example, anyone

who den i e s having eve r l ied i n the past would be ly ing , which

is reflected on t h e tracings of t h e polygraph. The DLT

assumes t h a t an innocent examinee w i l l be more d i s tu rbed when

i n s t r u c t e d t o answer f a l s e l y about some p a s t misdeed than

when t r u t h f u l l y denying a n accusa t ion of which he or she now

is suspected of having pe rpe t r a t ed . The DLT is scored i n t h e

same way as t h e CQT.

Advocates be l i eve t h a t t h e DLT is an improvement because

t h e r e is greater c e r t a i n t y t h a t t h e examinee's answers t o

d i r e c t e d - l i e ques t ions are f a l s e . Moreover, t h e y claim t h a t

t h e DLT i s a more

same d i r e c t e d - l i e

s t andard ized test t h a n t h e CQT because t h e

ques t ions can be used in every case.

However, t h e assumption of t he DLT, t h a t is, t h e innocent

examinee is more d i s tu rbed when answering f a l s e l y to t h e

d i r e c t e d - l i e ques t ions , seems ve ry moot because one can never

know whether t h e examinee is r e a l l y more d i s tu rbed by t h e

ques t ions . Indeed, it seems l i k e l y t h a t na ive and innocent

examinee w i l l show s t r o n g responses to t h e r e l e v a n t

ques t ions , n o t to t h e d i r e c t e d - l i e ques t ions , because t h e

examinee is w e l l aware t h a t t h e r e l e v a n t ques t ions are more

important for t h e outcome of t h e test. Moreover, t h e

psychologica l impact of t h e directed-lie ques t ions ( e . g . ,

"Have you e v e r l i e d ? " ) seems less t h a n t h e impact of t h e

"control11 q u e s t i o n s i n t h e CQT (e.g., "Apart from t h e p r e s e n t

i n c i d e n t , did you e v e r t a k e something t h a t d i d not belong t o

you? l1 ) , and even much less t h a n t h e impact of t h e r e l e v a n t

ques t ions (e.g., "Did you t a k e money?"). Thus t h e r e s u l t of

t h e i n c r e a s e d use of t h e DLT, i n t h e name of a more

s t andard ized l ie d e t e c t i o n method, might be an inc reased

number o f f a l s e - p o s i t i v e c l a s s i f i c a t i o n s . . n n . important

a spec t of t h e polygraphic examinat ion is t h e i n t e r p r e t a t i o n

of t h e p h y s i o l o g i c a l responses. Current ly , t h e r e are two

types of s c o r i n g method used: q u a l i t a t i v e and semi-

q u a n t i t a t i v e . The q u a l i t a t i v e method c o n s i s t s of s imply

i n s p e c t i n g t he shape of t h e responses and dec id ing whether

t h e person has been decept ive by g e n e r a l l y responding more t o

relevant questions (see Reid & Inbau, 1977). This

impressionist ic method would be pa r t i cu la r ly e f f e c t i v e i f

there were "specific l i e responses" t h a t would be e a s i l y

ident i f ied . However, t h i s is not t h e case. Unfortunately,

t h e method is s t i l l employed by most f i e l d polygraphers

(Furedy & Heslegrave, 1991).

The semi-quantitative method, which has been recommended

by the CQT advocates (see Barland & Raskin, 1975), assigns

numbers (ranging from -3 t o +3) t o each pa i r of

re levant /control questions for each physiological measure,

depending on t h e r e l a t i v e magnitudes of t h e responses to each

question, I f t h e relevant question y ie lds a grea ter

response, then t h e s ign of t h e number i s negative; i f t h e

reverse is t r u e , t h e s ign is pos i t ive . The scores are

summed, using question pairs (usually three), physiological

measures ( t h r e e o r four), and a t lest three "tests." If t h e

absolute value of t h e sum exceeds 5, then, depending on t h e

sign of number, t h e examinee is c l a s s i f i e d a s deceptive

(negative s i g n ) o r t r u t h f u l (pos i t ive s ign) , I f t h e scores

f a l l s between -5 and +Sf t h e examinee i s c la s s i f i ed as

" inconclusive . " One bas ic problem of t h e method is t h a t t h e score

(ranging from -3 t o +3) is assigned by subjective and

qua l i t a t ive means. Secondly, t h e s e t t i n g of t h e cutoff point

(-6 o r +6) for inconclusive is a rb i t r a ry . I n addit ion, t h e r e

is no allowance f o r number of physiological measures and

number of t e s t s - Thus, t h e chances of scoring an examination

inconclusive cou ld be decreased as a func t ion of t h e sum of

the number o f channels used and tests administered. These

a r b i t r a r i n e s s f e a t u r e s severe ly weaken t h e o b j e c t i v i t y of t h e

CQT . To coun te r t h e s e claims, a computerized evaluat ion

system f o r polygraph data was developed by Kircher and Raskin

(1988). However, Furedy (1987) descr ibed it as "garbage-in,

garbage-out." If t h e CQT process i t s e l f is unreasonable, t h e

output of t h e computer is s t i l l unreasonable. Moreoverr, t h e

system does n o t seem t o subdue t h e i n h e r e n t problems of t h e

CQT, although it could increase i ts f a c e v a l i d i t y value.

ms an -. Since t h e

beginning of polygraph use, polygraph examiners had used

"global eva lua t ion" (e.g. , Reid & Inbau, 1977 ) . The same

ind iv idua l reads t h e case f i l e , conducts t h e p r e t e s t

interview, formulates t h e quest ions, adminis ters t h e tests,

observes t h e "behavior symptoms," eva lua t e s t h e polygraph

cha r t s , and then reaches t h e f i n a l d iagnos i s of decept ive or

t r u t h f u l (Lykken, 1998). Hence, dur ing t h e course of the

procedure, a g r e a t deal of complex informat ion is a v a i l a b l e

t o t h e examiner, and it is impossible t o d i f f e r e n t i a t e

between t h e impressions formed by t h i s p r i o r information and

those gained from t h e purely phys io log ica l data obtained

during t h e so-called test phase of t h e polygraph

in t e r roga t ion procedures. This f e a t u r e , which cha rac t e r i ze s

all types of polygraph-based i n t e r r o g a t i o n procedures, but i n

p a r t i c u l a r t h e CQT, has been l abe l ed "contamination" (Ben-

Shakhar, B a r - H i l l e l , 6; Lieblich, 1986), meaning t h a t

judgments and conclusions derived from t h e physiological

information are contaminated with var ious kinds of non-

physiological information.

The contamination problem is p a r t i c u l a r l y severe when

t h e i n t e r p r e t a t i o n of t h e physiological c h a r t s i s

impress ion is t i c and subject ive . When no clear a p r i o r i r u l e s

of chart i n t e r p r e t a t i o n e x i s t , t h e i n t e r p r e t a t i o n depends

upon t h e judgment of t h e examiner, who cannot ignore t h e

p r i o r information t h a t was provided.

Another poss ib l e contamination problem is t h a t t h e non-

physiological information may inf luence t h e manner i n which

t h e polygraph i n t e r r o g a t i o n is conducted. I n t h e course of

p r e t e s t in te rv iew and/or when reading t h e case f i l e , it is

l i k e l y t h a t t h e examiner forms an opinion of whether t h e

examinee i s g u i l t y or not , and then t h e examiner's opinion

may a f f e c t t h e way t h e in te r roga t ion is conducted. I n

addit ion, and perhaps more s ign i f i can t ly , a p r i o r impression

t h a t t h e examinee is probably g u i l t y can lead t o the examiner

formulating r e l a t i v e l y ine f f ec t ive con t ro l questions. Such

an "experimenter expectancy e f f e c t " has been w e l l documented

(e.g., Rosenthal & Rubin, 1978) both i n l abo ra to r i e s and

r e a l - l i f e s i t u a t i o n s ; and it is genera l ly demonstrated t h a t

expectat ions formed by an experimenter may influence t h e

behavior of sub jec t s .

Because t h e CQT includes t h e p r e t e s t in terview as an

e s s e n t i a l p a r t of procedure, i n which so-called cont ro l

ques t ions are formula ted through t h e i n t e r a c t i o n between t h e

examiner and examinee, it would be impossible t o overcome

t h e s e contaminat ion problems.

confession. According t o p r a c t i c i n g polygraphers

(e.g., Lee, 1953) , an important func t ion of t h e polygraph is

n o t only i ts use as a d e t e c t o r of decept ion, b u t also its use

t o induce a confess ion . This raises t w o basic problems

concerning the CQT; one is e t h i c a l and t h e o t h e r i s

s c i e n t i f i c . The e t h i c a l problem is t h a t t h e confession-inducing

func t ion can be admin i s t e red independent of t h e r e s u l t of

psychophysiological d e t e c t i o n . Even i f an examiner is not

s u r e t h a t an examinee is l y i n g , t h a t doubt is reso lvab le by

p ress ing t h e examinee i n t o a confession of g u i l t , asserting

t h a t t h e 'machine' indicates t h a t t h e examinee has been l y i n g

(Furedy & Heslegrave, 1991). This is p a r t i c u l a r l y l i k e l y

wi th t h e uns tandardized CQT, i n which a n examiner is induced

to form h i s or h e r own opin ion f o r a n examinee through an

ex tens ive i n t e r a c t i o n d u r i n g t h e p r e t e s t in terv iew, the case

record reading , and t h e behaviors of t h e examinee dur ing t h e

interview. Moreover, t h e r e is the l o g i c a l p o s s i b i l i t y t h a t

c e r t a i n confess ions obtained by such "psychological-rubber-

hose" (Furedy & L i s s , 1986) or "fourth-degree" (Lykken, 1981)

procedures may be false. I n f a c t , many false confessions

have been made by innocent persons i n c r i m i n a l cases without

a " t h i r d degree" procedure (Gudjonsson, 1992) .

The s c i e n t i f i c problem is t h a t one can never estimate

t h e accuracy of t h e CQT as a pure psychophysiological

de tec t ion technique, as long as t h e confession-inducing

function is regarded as a part of t h e CQT procedures. In

o t h e r words, it is impossible t o d i s t i ngu i sh whether t h e

f i n a l judgment by t h e polygrapher on an examinee's g u i l t has

been provided by confess ion or physiological recordings, or

both*

Accordingly, t h e CQT i s not a sc ien t i f i c -based technique

t o d e t e c t deception or t o discr iminate between honest and

deceptive ind iv idua ls - The only way t o overcome t h e

d i f f i c u l t i e s mentioned above is by completely decontaminating

t h e procedures, us ing a standardized i n t e r r o g a t i o n method and

ob jec t ive measurements (Ben-Shakhar, 1991; Ben-Shakhat &

Furedy, 1990). However, it seems impossible t o decontaminate

t h e CQT because i ts t h e o r e t i c a l basis is s c i e n t i f i c a l l y

unsound and obscure-

G u i l t y - Test ! C i a

An a l t e r n a t i v e and less cont rovers ia l de t ec t ion

technique is t h e Gu i l ty Knowledge T e s t (GKT) , also known as

Concealed Information T e s t ( C I T ) , which is commonly used i n

laboratory experiments but less i n f i e l d p r a c t i c e . The GKT

was developed by Lykken (1959, 1960) based on e n t i r e l y

d i f f e r e n t assumptions from t h e CQT as follows: (a) The

purpose of psychophysiological detect ion i n c r imina l cases is

de tec t ing g u i l t r a t h e r than de tec t ing deception, ( b ) a g u i l t y

person possesses s p e c i f i c information concerning a crime

which is not usua l ly available to innocent persons (e.g.,

g u i l t y knowledge), and (c) recogni t ion of p ieces of

information unique t o t h e crime w i l l lead t o an enhanced

physiological response t o them only i n t h e g u i l t y person.

To s a t i s f y t h e s e presumptions, t h e GKT u t i l i z e s

multiple-choice quest ions , each having one re levant

a l t e r n a t i v e (e.g., a t r u e f e a t u r e of a crime) and severa l

neu t r a l , i r r e l e v a n t a l t e r n a t i v e s . The a l t e r n a t i v e s are

chosen s o t h a t an innocent person w i t h no g u i l t y knowledge

cannot d iscr iminate among them (Lykken, 1981), f o r example,

"Was t h e weapon used i n t h e p a r t i c u l a r case a : A) gun, B)

kn i fe , C ) lead pipe, D ) c lub, or E ) basebal l bat?" Since it

is assumed t h a t t h e t r u e weapon is known only t o a person

involved i n t h e crime, t h i s weapon has a s p e c i a l meaning only

for t h i s person. I f t h e person ' s physiological responses to

t h e re levant i t e m are c o n s i s t e n t l y l a rge r than t o t h e neu t r a l

ones, knowledge about t h e event i n quest ion (e.g., crime) is

in fe r r ed . I n c o n t r a s t , an innocent suspect with no g u i l t y

knowledge should no t respond d i f f e r e n t l y to t h e a l t e rna t ives .

Naturally, a s i n g l e p resen ta t ion of one question with a

f e w a l t e r n a t i v e s would no t be s u f f i c i e n t because an innocent

suspec t might then show g r e a t e r response to t h e cor rec t

a l t e r n a t i v e j u s t by chance (Leo , a fa l se -pos i t ive e r r o r ) .

To prevent such an occurrence, t h e GKT uses severa l d i f f e r e n t

quest ions t h a t focus on d i f f e r e n t fea tures of t h e crime

(e.g., t h e kind of c l o t h e s t h e vic t im wore, t h e amount of

money s t o l e n ) and by f requent ly repea t ing each series of

quest ions . With only 10 such g u i l t y knowledge i t e m s , each

wi th f i v e good a l t e r n a t i v e s , t h e r e would be only about 1

chance in 10 mil l ion t h a t t h e suspect without g u i l t y

knowledge w u l d provide h i s o r h e r l a r g e s t response t o t h e

correct a l t e r n a t i v e i n a l l 10 items (Lykken, 1974).

Unlike t h e CQT, t h e GKT rests on sound

psychophysiological and psychological p r inc ip l e s as a

s tandard izab le test or detector of g u i l t , although it does

n o t detect deception d i r e c t l y . Advantages of t h e GKT as a

s c i e n t i f i c method over t h e CQT are summarized as follows: (a)

use of sound s c i e n t i f i c "control" quest ions , (b) ease of

s tandard iza t ion of t h e method, and (c) a less contaminated

procedure. These advantages w i l l be b r i e f l y described below.

ol -. The c o n t r o l quest ions i n t h e

GKT are formulated exac t ly like t h e r e l evan t ones. The only

d i f f e r e n c e between t h e r e l evan t and c o n t r o l quest ions is t h a t

on ly t h e re levan t quest ions r e f e r t o t r u e f ea tu re s of the

e v e n t under invest igat ion. Therefore, only people possessing

such knowledge (Le. , g u i l t y knowledge) are capable of

d i s t i ngu i sh ing re levan t from con t ro l quest ions. The

recogni t ion then leads t o d i f f e r e n t i a l psychophysiological

r e spons iv i ty t o t h e re levan t quest ions only by t h e g u i l t y

person. This aspect is not accomplished i n t h e CQT, i n which

all ques t ions , both t h e re levan t and c o n t r o l quest ions, are

s e r i o u s to an examinee b u t t h e i r degrees of d i f f e r e n c e are

never known.

. In t h e GKT, t h e q u e s t i o n s are

determined by t h e f e a t u r e of t h e even t under i n v e s t i g a t i o n ,

and t h e y do n o t depend on t h e examiner-examinee i n t e r a c t i o n

like i n t h e CQTw It i s p o s s i b l e t h a t t w o different examiners

would c o n s t r u c t d i f f e r e n t sets of ques t ions from the f e a t u r e s

of an even t , b u t t h e s e two GKT procedures may be viewed as

two e q u i v a l e n t forms of a vocabulary test, each c o n t a i n i n g

d i f f e r e n t items sampled from t h e set of words (Ben-Shakhar &

Furedy, 1990). I n a d d i t i o n , t h e set of ques t ions i n t h e GKT

can be prepared i n advance on t h e b a s i s of a thorough

examinat ion of t h e even t and even t h e same set of ques t ions

can be a p p l i e d to d i f f e r e n t examinees. Such a procedure is

more s t a n d a r d and objective t h a n is t h e case i n the CQT.

Lesscontamination in mentioned

p rev ious ly , t h e whole CQT procedure r e q u i r e s an e x t e n s i v e

examiner-examinee i n t e r a c t i o n , e s p e c i a l l y i n t h e pretest

in te rv iew, and this leads to contaminat ion i n t h e examiner ' s

f i n a l judgment whether t h e examinee is g u i l t y or not.

However, t h e GKT does no t r e q u i r e the p r e t e s t i n t e r v i e w t o

c o n s t r u c t ques t ions and t h u s t h e examiner can be freer from

any bias a g a i n s t t h e examinee. Moreover, t h e GKT can be

completely decontaminated f r o m tester b i a s e s by u s i n g b l i n d

i n t e r r o g a t i o n or even prerecorded ques t ions (Ben-Shakhar &

Furedy, 1990; Lykken, 1981).

I n summary, t h e GKT enab les s c i e n t i f i c exp lora t ion of

psychophysiological d e t e c t i o n of deception, al though it

purpor t s t o detect g u i l t y knowledge r a t h e r than deception

itself. Unfortunately, however, it has not been used widely

i n t h e f i e l d p r a c t i c e of criminal inves t i ga t i on i n North

America. Only Israeli and Japanese po l i ce polygraphers are

f requen t u s e r s of t h e GKT, and in t h e latter case, around

ha l f of some 5,000 annual polygraph examinations have been

carried o u t with the GKT (Ben-Shakhar h Furedy, 1990). The

l ack of f i e ld use of t h e GKT is p a r t l y due t o t h e reasonably

strict requirements of t h e test t o keep important d e t a i l s of

the crime from being revealed t o t h e publ ic i n genera l and t o

t h e var ious suspects i n p a r t i c u l a r . A requirement of t h e GKT

is t h a t an examiner be a v a i l a b l e who is w e 1 1 informed about

t h e cr ime so t h a t he o r she can find t h e "keys," t h a t is t o

say, t h e i tems of information t h a t on ly a g u i l t y suspec t

would recognize and t h a t cou ld be used as GKT ques t ions

(Lykken, 1991) .

I n l abora to ry s t u d i e s , t h e GKT has proven t o be q u i t s

r e l i a b l e i n de t ec t i ng g u i l t (e.g., Ben-Shakhar, L ieb l ich , &

Kugelmass, 1970; Davidson, 1968; Dawson, 1980; Furedy & Ben-

Shakhar, 1991; Gustafson & O n e , 1963, 1965; L ieb l ich , Ben-

Shakhar, & K u g e b s s , 1976; Lykken, 1959, 1960). Ben-Shakhar

and Furedy (1990) provided t h e average accuracy rates a f t e r

reviewing 10 GKT l abora to ry s t u d i e s , which had been

o r i g i n a l l y designed t o examine t h e v a l i d i t y of t h e method.

The accuracy r a t e f o r g u i l t y p a r t i c i p a n t s w a s 84%, and 94%

among those simulating t h e innocent persons. They also

provided t h e average accuracy rates of t h e CQT i n both

labora tory mock crime s t u d i e s and f ie ld s tudies . The r e s u l t s

of t h e 9 m c k cr ime s t u d i e s revealed 80% co r r ec t

c l a s s i f i c a t i o n of t h e g u i l t y p a r t i c i p a n t s and 63% of t h e

innocent persons, while t h e review of 9 f i e l d s t u d i e s

provided t h e accuracy rates of 84% f o r t h e guilty suspec t s

and 72% for t h e innocent suspects . I t should be pointed o u t

that both t h e GKT and CQT c o r r e c t l y i d e n t i f i e d g u i l t y

sub j ec t s around 80% of t h e t i m e , b u t t h e CQT's accuracy rates

f o r innocent persons were s u b s t a n t i a l l y lower compared wi th

t h e GKT. This means r e l a t i v e l y high fa l se -pos i t ive e r r o r s

occurred w i th t h e CQT. Overall, Ben-Shakhar and Furedy

( 1 9 9 0 ) concluded that t h e GKT is t h e method which can b e s t

p ro t ec t t h e innocent and recommended abandoning t h e CQT.

SCOPE OF THE STUDY

I n t h e psychophysiological de t ec t ion of deception, t h e

GKT is apparent ly a f a r more ob jec t ive way of d i s t i ngu i sh ing

between g u i l t y and innocent suspects , but less f requent ly

used i n f i e l d p r a c t i c e than t h e more con t rovers ia l CQT. To

t h e e x t e n t t h a t applied psychology professes i t s e l f t o be

based on s c i e n t i f i c knowledge, s tandard iza t ion of t h e method

and explanat ion of i t s underlying mechanism are e s s e n t i a l

requirements. I n an e f f o r t t o con t r ibu t e towards a f u l l e r

understanding and s tandard iza t ion of t h e GKT, t w o d i f f e r e n t

experiments were c a r r i e d o u t t o examine accuracy of t h e GKT

i n a labora tory s i t u a t i o n where p a r t i c i p a n t s role-played a

crime scenario.

Experiment I w a s a conceptual r e p l i c a t i o n of a GKT

laboratory s tudy by Nakayama, Mizutani, and Kizaki (1988),

who repor ted t h a t de tec t ion w a s super io r when p a r t i c i p a n t s

were required t o delay t h e i r answers f o r 8 seconds r a t h e r

than answer immediately as is CuStO-m I n t h e i r

experiment, t h e GKT quest ions were presented i n a v i s u a l mode

on computer screen--a more standardized procedure t han t h e

usual one i n which a human examiner asks t h e quest ions. I f

t h e r e s u l t by Nakayama et a l e ' s (1988) s tudy is aga in

confirmed i n another experiment, a simple procedural change

requ i r ing delayed-answer would produce improved de tec t ion .

I n Experiment 11, an audi to ry , computer-synthesized

voice p resen ta t ion of t h e GKT w a s employed, and t h e

p a r t i c i p a n t ' s emotional r eac t ion t o t h e re levan t items w a s

manipulated i n hope of changing t h e i r "s ignal values" (e.g.,

Lykken, 1974). I n addit ion, to examine an or ienta t ion and

habi tuat ion account of the GKT e f f e c t (e.g,, Ben-Shakhar,

1977; Lieblich, Rugelmass & Ben-Shakhar, 1970; Lykken, 1974;

Raskin, 1979), a simple o r i en t ing response (OR) paradigm f o r

obtaining pa r t i c ipan t s ' skin conductance response (SCR)

c h a r a c t e r i s t i c s t o repeated s t i m u l i w a s carried out p r i o r t o

t h e de tec t ion phase, and several components of OR were

compared t o t h e GKT e f f ec t s .

I n both experiments, SCR were used as a dependent

var iable . The SCR has been proven t o be t h e m o s t e f f i c i e n t

psychophysiological measure, both i n laboratory s tud ies and

field practice of detect ion of deception (e.g., Barland &

Raskin, 1973; Cutrow, Parks, Lucas, & Thomas, 1972; Elaad &

Ben-Shakhar, 1989; Furedy & Heslegrave, 1988; Podlesny &

Raskin, 1977; Thackray & Orne, 1968; Waid, Orne, Cook, O r n e ,

1981).

EXPERIMENT I

The primary purpose of t h e Experiment I w a s t o provide a

conceptual r e p l i c a t i o n of a GKT laboratory s tudy by Nakayama

e t a L (1988). They reported, w i th SCR as dependent measure,

no t only t h a t t h e delayed-answer cond i t i on was s u p e r i o r t o

detect g u i l t y , bu t a l s o t h a t t h e inaru?diate-answer condi t ion

f a i l e d to y i e l d a reliable GKT effect.

The delayed-answer condi t ion was o r i g i n a l l y in t roduced

by Dawson (1980) i n h i s l abo ra to ry ve r s ion of t h e CQT t o

s e p a r a t e two hypothet ica l processes involved i n t h e deception

phenomenon, namely t h e i n t e n t i o n t o deceive and t h e act of

deception. Thus, psychophysiological responses were measured

t w i c e i n t h e delayed-answer condi t ion: one immediately a f t e r

ques t ion onse t and t h e o t h e r immediately a f t e r t he

p a r t i c i p a n t ' s answer. It was conceptual ized t h a t t h e former

measure was an index of t h e i n t e n t i o n t o deceive, and t h e

lat ter w a s an index of t h e act of deception. Dawson ( 1 9 8 0 )

found a g r e a t e r d i f fe rence between r e l e v a n t and c o n t r o l

ques t ions when electrodermal responses t o t h e ques t ion onse t

were used as a de tec t ion measure, and hence concluded t h a t it

w a s t h e i n t e n t i o n t o deceive r a t h e r t han act of decept ion

t h a t w a s critical f o r t h e d e t e c t i o n of deception i n t h e CQT.

However, t h e r e was no d i f f e r ence between t h e immediate-answer

and delayed-answer condi t ions when t h e electrodennal

responses t o t h e quest ions were compared.

Later, Furedy and Ben-Shakhar (1991) adopted t h e

delayed-answer condi t ion i n a d d i t i o n t o t h e conventional

immediate-answer condi t ion t o s tudy t h e r o l e of deception in

t h e GKT. They found equa l ly s i g n i f i c a n t de tec t ion rates when

p a r t i c i p a n t s ' SCRs were obtained inmediately fol lowing

ques t ion p re sen t a t i on , whether t h e p a r t i c i p a n t s had answered

immediately or had delayed t h e i r answers. I n c o n t r a s t , t h e

d i f f e r e n t i a l SCR t o t h e delayed answer was markedly

a t t enua ted , Based on t h e i r r e s u l t s , Furedy and Ben-Shakhar

(1991) also suggested t h a t the crucial f a c t o r determining

d i f f e r e n t i a l r espons iv i ty t o the r e l evan t and n e u t r a l items

is t h e i n t e n t i o n t o deceive r a t h e r than act of deception.

Contrary t o o t h e r l abora to ry GKT s tud i e s , Nakayama et

al. (1988) failed t o ob ta in a r e l i a b l e GKT e f f e c t i n t h e

immediate-answer condit ion, bu t obta ined a s i g n i f i c a n t GKT

e f f e c t in t h e delayed-answer condi t ion . Hence they

recommended the use of the delayed-answer condi t ion i n t h e

f i e l d p r a c t i c e of t h e GKT t o produce improved de tec t ion .

T h e i r p r e s e n t a t i o n method of GKT quest ions , however, v a r i e d

from t h e normal p r a c t i c e i n s e v e r a l ways. F i r s t , t h e GKT

quest ions were presented on a computer screen i n a v i s u a l ,

r a t h e r t han a u d i t o r y mode. Thus it seems d i f f i c u l t t o

genera l i ze t h e r e s u l t of the Nakayama e t a l . s tudy i n t o f i e l d

p r a c t i c e i n which a human examiner presents ques t ions o r a l l y .

The second d e v i a t i o n i n t h e i r method was t h a t t h e ques t ion

remained on a computer screen f o r 8 s, no matter whether t h e

p a r t i c i p a n t s had answered immediately o r had delayed t h e i r

answers f o r 8 s. I n t h e immediate-answer condit ion,

the re fore , t h e GKT ques t ion wlauld have remained on sc reen

long af ter t h e p a r t i c i p a n t had answered it, and t h i s raises

t h e p o s s i b i l i t y t h a t , a t least f o r some p a r t i c i p a n t s , t h e

immediate-answer c o n d i t i o n may have seemed t o l a c k sense, and

could have accounted for t h e s e i n v e s t i g a t o r s ' f a i l u r e t o f i n d

any reliable GKT e f f e c t under t h i s convent ional condi t ion.

I n other words, some p a r t i c i p a n t s i n the immdiate-answer

cond i t ion may n o t have treated t h e i r t a s k as s e r i o u s l y as t h e

p a r t i c i p a n t s in t h e delayed-answer c o n d i t i o n , because t h e

ques t ions were remaining on without any s p e c i f i c s e n s i b l e

purpose. Moreover, t h e p a r t i c i p a n t s cou ld have answered

without paying any a t t e n t i o n t o t h e very o n s e t of quest ion.

To prevent t h i s problem, Nakayama e t al . reques ted t h e i r

p a r t i c i p a n t s t o r e p e a t t h e name of i t e m t h a t was presented on

t h e computer s c r e e n as an i n t e r r o g a t o r y . Aside from

s p e c u l a t i v e n a t u r e of t h e i r a t t e n t i o n a l hypothesis , it is no t

clear t h a t t h e word r e p e t i t i o n procedure e l i m i n a t e s t h e

a t t e n t i o n a l d i f f i c u l t y confound. M o r e impor tant ly , however,

it does n o t deal wi th t h e o r i g i n a l problem of t h e ixnmediate-

answer version of t h e t a s k .

T o make t h e computerized GKT procedure more l i k e t h e

normal oral arrangement, t h e p r e s e n t experiment introduced an

a d d i t i o n a l immediate-answer cond i t ion , where t h e ques t ions

disappeared from a computer sc reen a s soon as p a r t i c i p a n t s

gave t h e i r oral answers (Immediate-Answer-Contingent

c o n d i t i o n ) . T h i s was c a r r i e d o u t by r e q u e s t i n g p a r t i c i p a n t s

to h i t a computer key s imultaneously when t h e y gave t h e i r

oral answers, which means t h e d u r a t i o n of ques t ions on

computer sc reen was depending on p a r t i c i p a n t s ' oral answers.

The answer-dependent procedure was also appl ied t o t h e

delayed-answer condi t ion where p a r t i c i p a n t s were requ i r ed t o

delay t h e i r answers f o r 8 s and t h e n h i t a computer key t o

e r a se ques t ions ( Delayed-Answer-Contingent condi t ion) . In

addi t ion to t h e s e d i f i e d condi t ions , t h e o r i g i n a l

arrangement by Nakayama et a l . of t h e ques t ion being on

screen for 8 s was carried ou t both in t h e hmdiate- and t h e

delayed-answer condi t ions (Immediately-Answer-Non-contingent

and Delayed-Answer-Non-contingent condi t ions , r e s p e c t i v e l y ) .

I n t h e l i g h t of t h e Nakayanu et al . (1988) s tudy, the

present experiment explored t h e s e independent va r i ab l e s to

shed more l i g h t on t h e i r role in t h e GKT e f f e c t ,

of v t I

A 2 x 2 x 2 x 2 (Quest ion Type x I n t e r v a l x Contingency

x Stimulus Type) mixed-design w i t h repeated measures on

Quest ion Type and Stimulus Type was used, The Quest ion Type

var iab le r e f e r s t o t h e re levan t and n e u t r a l quest ions: t h e

va r i ab l e t h e most crit ical in t h e GKT s tudy, which was a

'wi th in ' factor. The I n t e r v a l variable r e f e r s t o t h e

immediate- ve r sus delayed-answer condi t ions , and t h e

Contingency v a r i a b l e refers to t h e du ra t i on of t h e ques t ion

on computer sc reen , which was c o n t r o l l e d by the p a r t i c i p a n t ' s

key response. These two f a c t o r s were examined as 'between'

f a c t o r s and hence generated a total of fou r d i f f e r e n t groups

of p a r t i c i p a n t s described above. F ina l l y , t h e Stimulus Type

v a r i a b l e refers to t h e two types of s t imulus which were

provided f o r each ques t ion item; one was t h e ques t ion i t s e l f

and t h e o t h e r was a tone st imulus p resen ted 8 s a f t e r the

quest ion onse t . The lat ter o r i g i n a l l y served as a prompt t o

give o r a l answers by p a r t i c i p a n t s i n t h e delayed-answer

groups b u t was also presented t o t h e m d i a t e - a n s w e r groups

just to e q u a l i z e experimental condi t ions . Thus t h i s variable

was also a * w i t h i n v f ac to r . T o examine t h e s e independent

variables, SCR was used as a dependent measure.

Method

The p a r t i c i p a n t s were 24 male and 24 female volunteers ,

aged 19-39 yea r s , from t h e Int roductory Psychology class a t

t h e Univers i ty of Toronto. P r i o r t o obta ining t h e i r consent,

it w a s expla ined t o t h e p a r t i c i p a n t s t h a t they were being

asked t o p l ay the role of a bu rg l a r in t h e experiment. A l l

of them were willing t o play t h i s role. None of t h e

pa r t i c ipan t s had previously taken p a r t i n a detection-of-

deception study. They were randomly assigned t o one of fou r

groups of 12 p a r t i c i p a n t s each wi th a r e s t r i c t i o n t h a t each

group had 6 female and 6 male p a r t i c i p a n t s .

Aooaratus

The p a r t i c i p a n t s were tested in a sound at tenuated one-

way v i s ion room, which w a s descr ibed as " in terrogat ion room"

and was l oca t ed adjacent t o t h e exper imenter ' s room; it was

lit with a 100 w l i g h t s i t u a t e d overhead and to t h e back of

t h e pa r t i c ipan t .

The p a r t i c i p a n t s were seated on a one-armed c h a i r i n

f r o n t of a lap- top computer (Toshiba J3100-GT) with 9 inch

monitor and a keyboard and t w o o u t s i d e speakers.

Ins t ruc t ions about t h e procedure as w e l l as a l l quest ions

during t h e d e t e c t i o n period were provided in v i sua l mode on

t h e computer screen. The computer a l s o produced a beeping

tone during t h e matching t r ia l , where pa r t i c ipan t s ' o r i e n t i n g

responses t o simple tone s t i m u l i were evaluated. The tone

was 80 dB a t speaker l e v e l , 2500 Hz, and 800 m s i n dura t ion .

I t w a s presented f i v e times with a fixed in ter -s t imulus-

i n t e r v a l of 30 s. The computer program c o n t r o l l i n g t h e

experimental procedure w a s w r i t t e n in Microsoft w i c k B a s i c

4.5@.

Continuous skin conductance was recorded with a

Coulbourn InstruIllents preampl i f ier (S71-22) on a Narco Bio-

Systems M K - 1 1 1 4 (physiographa) polygraph running a t a c h a r t

speed of 0.5 c m h . Two Ag/AgCl e l e c t r o d e s (8-mm i n

diameter), i n conjunct ion w i t h commercial e l e c t r o l y t e from

T e c a Corp, were a t t a ched by double-sided adhesive c o l l a r s t o

t h e volar su r f ace s of t h e p a r t i c i p a n t ' s distal phalanges of

t h e f i r s t and t h i r d f i nge r s of t h e left hand, which had been

cleaned wi th Isopropyl rubbing alcohol .

Procedure

When p a r t i c i p a n t s a r r ived f o r t h e experiment, they w e r e

gree ted by t h e e x p e r i m n t e r and t hen g iven genera l

information concerning t h e nature of t h e experiment. They

were t o l d t h a t t h e purpose of t h e experiment was t o examine

t h e r e l i a b i l i t y of a computer-assisted d e t e c t i o n of deception

( l i e d e t e c t i o n ) . T h e i r t a s k w a s t o p lay , i n an imagined

crime s i t u a t i o n , t h e r o l e of burg la r who faced a polygraph

test he or she w a s t r y i n g t o beat i n order to be released by

t h e police, The p a r t i c i p a n t s were also t o l d t h a t two

e l ec t rodes would be a t tached t o two f i n g e r s of t h e i r l e f t

hands before s t a r t i n g t h e experiment, It w a s f u r t h e r

explained t h a t t h e s e were only recording electrodes f o r

de tec t ion of deception, and t h e p a r t i c i p a n t s would not

experience any discomfort from t h e electrodes. F ina l ly ,

p a r t i c i p a n t s were t o l d t h a t t h e experiment i t s e l f would last

for approximately 30 minutes.

Following general information on t h e running of t h e

experiment, each pa r t i c ipan t s igned an informed consent which

s t a t e d t h a t t h e pa r t i c ipan t was aware of t h e nature of the

experiment and t h a t he o r she could terminate t h e experiment

a t any t ime with impunity.

The p a r t i c i p a n t s were then led i n t o a room described as

t h e " in t e r roga t ion room," adjo in ing t h e one used f o r t h e

physiological recording by t h e experimenter. The

p a r t i c i p a n t s were seated a t a table fac ing t h e computer and

then electrodes were attached f o r SCR measurement. Once t h e

e lec t rodes were i n place, t h e p a r t i c i p a n t s were asked to rest

t h e l e f t hand on a s o f t pad and t o keep it s t i l l and avoid

unnecessary movement.

Af t e r t h e completion of e l ec t rode attachment, t h e

p a r t i c i p a n t s were t o l d t h a t d e t a i l e d in s t ruc t ions f o r t h e

experiment and t h e descr ipt ion of t h e crime, f o r which the

p a r t i c i p a n t s had t o take a polygraph interrogat ion, would be

given on t h e computer screen i n w r i t t e n form. The

p a r t i c i p a n t s were then asked t o initiate t h e computer program

by h i t t i n g any key on t h e computer once they were ready.

While t h e p a r t i c i p a n t s were reading t h e ins t ruc t ions , t h e

experimenter went t o t h e experimenter 's room t o calibrate t h e

polygraph and t h e n re tu rned t o t h e p a r t i c i p a n t once polygraph

recording w a s ready.

On t h e f i r s t sc reen of t h e i n s t r u c t i o n s , t h e

p a r t i c i p a n t s were reminded aga in t o p l a y t h e role of a

burg la r and were g iven a background why t h e y had been brought

into t h e " i n t e r r o g a t i o n room" as suspec t s . Below are t h e

i n s t r u c t i o n s t h a t were presented on t h e f i rst screen.

As you a l r e a d y knw, t h i s experiment is about l ie de t ec t i on . The room you are now i n is an i n t e r r o g a t i o n room, Here, I would like you t o p l ay t h e role o f a bu rg l a r who a c t u a l l y committed a burglary and has been under arrest for t h a t reason,

But you are a tough c r im ina l and you have not confessed t o your crime dur ing normal i n t e r r o g a t i o n procedures. Although t h e p o l i c e are convinced t h a t you are t h e burg la r , t h e r e is not enough material evidence that you are g u i l t y .

So, t h e irritated police department decided t o make you t a k e a l ie d e t e c t i o n test, and you have agreed, T h a t ' s why you are here ,

I f you c a n b e a t t h i s l i e d e t e c t i o n test, you w i l l be

released.

D o you unders tand your r o l e ? I f not , p l e a se a s k t h e experimenter now,

Next, I ' l l e x p l a i n t h e cr ime you committed. You d o n ' t have t o memorize t h e details, J u s t try t o g r a sp t h e s i t u a t i o n in genera l .

On t h e bottom line of t h e screen, a note prompted t h e

p a r t i c i p a n t s t o advance t o t h e nex t sc reen by h i t t i n g any key

so t h a t t h e y could read i n s t r u c t i o n s a t t h e i r own pace. The

second s c r een was a crime scenar io t h a t read as follows:

The crime concerned here is, of course, t h e burglary.

The o t h e r day, a t midnight, someone broke i n t o a house i n a Toronto suburban area. A f t e r t h e po l i ce i n v e s t i g a t i o n s , it was revealed t h a t t h e burglar , maybe j u s t one burg la r , broke i n t o t h e house and s t o l e some amount of money and jewels. For tunate ly , no one in t h e family was h u r t because they a l l s l e p t deeply. From t h e s k i l l f u l way in which t h e burg la ry had been carried ou t , t h e p o l i c e i d e n t i f i e d and a r r e s t e d you a s t h e burg la r . You had t h r e e records of burglary before. But you were smart enough no t t o l e ave any material evidence t h i s time.

As I said before , the p o l i c e are convinced t h a t you are t h e bu rg l a r , but it is a l s o t r u e t h a t they have not enough evidence. You w i l l be released i f you can beat the fo l lowing l ie de t ec t i on test. I f you fail, you w i l l s t i l l be kept i n custody. Moreover, t h e r e s u l t of t he

test w i l l be used i n your t r ial as an evidence. Thus, try t o beat the following t e s t 1 1 1

Next, I ' l l exp l a in t h e experimental procedures.

On the next six screens , t h e gene ra l i n t e r roga t i on procedures

were expla ined t o t h e p a r t i c i p a n t s and then d i f f e r e n t

i n s t r u c t i o n s about a manner of responding to t h e

i n t e r roga to ry ques t ions were given, depending o n which group

each p a r t i c i p a n t had been allocated. A l l p a r t i c i p a n t s were

i n s t r u c t e d t h a t they would be reques ted t o choose one o u t of

f i v e s p o t s thorough which they had in t ruded the house as a

burg la r . They were a l s o told t h a t t h e aim of t h e fo l lowing

polygraph test was t o i d e n t i f y the spot t h a t each p a r t i c i p a n t

would chose by means of examination of psychophysiological

recordings. The p a r t i c i p a n t s t h e n p r ac t i c ed responding t o

dummy ques t ions in a way t h a t had been explained d i f f e r e n t l y

f o r each group u n t i l they felt comfor table t o do so.

After t h e completion of p r a c t i c e sess ion, t h e

p a r t i c i p a n t s were requested on t h e next screen t o select one

out of f i v e s p o t s which t hey had intruded a house as a

bu rg l a r by r e f e r r i n g t o a l ayou t s h e e t of t h e a l l eged house

(Appendix A ) , which had been pu t face down besides t h e

computer. On t h e sheet , des ign of a house and i ts l a y o u t

w i t h f i v e a l t e r n a t i v e burglary spots marked was presented.

These f i v e a l t e r n a t i v e s were "1) Entry, " " 2 ) Family room, "

" 3 ) Garage," " 4 ) Kitchen," and "5) Living room." The

p a r t i c i p a n t s were requested t o type t h e number key on t h e

computer keyboard which corresponded t o t h e selected spot

af ter t h e experimenter l e f t t h e i n t e r r o g a t i o n room. To

confirm t h e s e l e c t e d spo t , t h e p a r t i c i p a n t s were asked t o

type t h e same number key again on t h e next screen. No one

f a i l e d t o type t h e corresponding key t w i c e i n succession.

Following t h e choice of bu rg l a ry spo t , t h e p a r t i c i p a n t s

were requested t o i n i t i a t e t h e five minute base l ine pe r iod by

h i t t i n g any key once they were ready. During t h e b a s e l i n e

per iod , t h e p a r t i c i p a n t s were asked t o s i t q u i e t l y at ease

f o r f i v e minutes during which the computer screen went blank.

When t h e p a r t i c i p a n t h i t a key t o initiate the basel ine

period, t h e exper-nter turned on t h e recording apparatus.

I n t h e middle of t h e baseline period, t h e tone was presented

f i v e times by t h e computer, separated by fixed i n t e r v a l s of

30 s. This procedure, t h e matching tr ial , would l a t e r permit

assessment of t h e group d i f fe rences in skin conductance

responses t o simple s t imuli .

Af ter t h e f i v e minute base l ine period passed, t h e

computer le t t h e par t ic ipants know with several beeping tones

t h a t t h e base l ine recording had j u s t f inished and asked them

t o i n i t i a t e t h e detection period once they were ready. On

t h e same screen, t h e pa r t i c ipan t s were reminded of t h e break-

in spot they had previously chosen.

I n t h e detect ion period, each question was presented

with a fon t s i z e of approximate 1 4 points a t t h e center of

t h e computer screen, asking " D i d you break i n through t h e

entry?" There were f ive d i f f e r e n t questions i n which t h e

name of burglar ized spot was replaced among f ive a l t e r n a t i v e s

mentioned above. A l l t h e pa r t i c ipan t s were asked t o deny

every quest ion by saying o r a l l y "No, not t h e entry," i n which

t h e name of t h e spot had t o be changed correspondingly to t h e

question. Because t h e experimenter was i n t h e adjoining r o o m

t o monitor t h e i r physiological responses during t h e de tec t ion

period, t h e response method, namely, denying t h e spot o r a l l y

r a the r than simply say "no" as usual, gave t h e experimenter

feedback about t h e spot in t h e quest ion and enabled him t o

mark it on t h e recording c h a r t when t h e de t ec t i on process was

under way. Th is procedure also did no t let t h e p a r t i c i p a n t s

neg lec t t h e q u e s t i o n because t hey had t o name t h e s p o t i n

t h e i r answer t o each question.

For t h e p a r t i c i p a n t s in t h e Immdiate Answer-Non

cont ingent (IANC) condit ion, each ques t ion remained f o r 8 s

on t h e computer sc reen a f t e r i ts o n s e t and disappeared

au tomat ica l ly w i th a computer beep (70 dB SPL, 2500 H z and

800 m s i n d u r a t i o n ) . The p a r t i c i p a n t s were requested t o

respond i m m d i a t e l y following each ques t ion although t h e

ques t ion remained on t h e sc reen for awhile- In t h e Delayed

Answer-Non c o n t h g e n t (DANC ) condi t ion , again each ques t ion

remained f o r 8 s on t h e sc reen after i t s onset and

disappeared au tomat ica l ly wi th a computer beep, However, t h e

p a r t i c i p a n t s in t h i s condi t ion were requested t o respond only

immediately a f t e r t h e computer beep; i n o t h e r words, the

p a r t i c i p a n t s had t o delay t h e i r response for 8 s. These t w o

condi t ions were e x a c t r e p l i c a t i o n s of condi t ions used in t h e

Nakayama et a l - (1988) study.

I n t h e Immediate Answer-Contingent ( I A C ) condi t ion , t h e

p a r t i c i p a n t s were i n s t r u c t e d t o answer immediately a f t e r

ques t ion o n s e t and h i t a space bar a t t h e same t i m e t o g e t

t h e next ques t ion . After 8 s from ques t ion onset , a computer

beep w a s provided i n t h e same way as i n previous two

condi t ions . This procedure corresponds more c lose ly to t h e

non-computerized, oral p re sen t a t i on arrangement because a

ques t ion would disappear r a t h e r t h a n s t a y long a f t e r t h e

p a r t i c i p a n t s had given t h e i r answer. For t h e pa r t i c i pan t s of

t h e Delayed Answer-Contingent (DAC) condi t ion , each ques t ion

remained f o r 8 s a f t e r i ts onse t as i n t h e DANC condit ion.

After 8 s passed, t h e p a r t i c i p a n t s were prompted to give

t h e i r o r a l response by a computer beep and requested t o h i t a

space bar to g e t t h e next ques t ion a t t h e same time.

A series of ques t ions w a s cons t ruc t ed from t h e 5 spots

described above and repeated six times i n each pa r t i c ipan t .

The ques t ions were presented a t a f i x e d i n t e r v a l of 30 s and

t h e r e w a s a 60 3 pause between each series. The quest ions

w e r e presented a t random i n a series wi th a r e s t r i c t i o n t h a t

the first q u e s t i o n i n each series would no t be t h e re levan t

spot . Thus, t h e f i r s t quest ion in each series w a s treated as

a bu f f e r and would be excluded from t h e data analys is .

Finally, as an invasion spot, 4 p a r t i c i p a n t s chose

Entry, 10 p a r t i c i p a n t s chose Family r o o m , 22 pa r t i c ipan t s

chose Garage, 8 p a r t i c i p a n t s chose Kitchen and remaining 4

p a r t i c i p a n t s chose Living room du r ing t h e spot-select ion

period.

SCR w a s de f ined as any response t h a t was i n i t i a t e d

(showing an i n f l e c t i o n p o i n t ) w i th in 1 t o 5 s following

st imulus o n s e t and producing a t least a 0.5 mm change on t h e

chart. Magnitude ( i n mm) w a s expressed as t h e d i f fe rence

between response o n s e t ( i n f l e c t i o n p o i n t ) and t h e h ighes t

point following response onse t u n t i l t h e end of t h e I t o 5 s

l a t ency window, SCRs with a change of less than 0 - 5 mm on

t h e c h a r t were scored as zero responses, In cases where a

composite of curves occurred, t h e measure taken was f r o m t h e

f i r s t curve, I n t h e matching t r i a l , SCRs were measured

following t h e s imple tone onset , Because t h e s imple t one was

de l ive red f i v e t imes i n t h e matching t r i a l , each p a r t i c i p a n t

produced f i v e SCR scores, I n t h e d e t e c t i o n period, SCRs were

measured t w i c e for each ques t ion both i n the 1-diate and

Delayed Answer condi t ion- - f i r s t , a f t e r ques t ion onse t , and

second, a f t e r t one onset , which w a s o r i g i n a l l y introduced t o

prompt t h e p a r t i c i p a n t s i n t h e Delayed Answer condi t ion t o

g ive t h e i r answers. Before s tat ist ical t rea tment , t h e SCR

scores were range transfornmd ( c f , Davey & Singh, 1988;

Lykken, 1 9 7 2 ) by d iv id ing every score obtained by a

p a r t i c i p a n t w i t h t h e maximum score obta ined t h a t p a r t i c i p a n t

dur ing t h e experiment.

I n add i t i on , an at tempt was made t o c l a s s i f y

p a r t i c i p a n t s as "gu i l t y " or "innocent" using a procedure

proposed by Lykken ( 1 9 5 9 ) , al though t h e p a r t i c i p a n t s in this

experiment were a l l g u i l t y of t h e imagined burglary. I n a

series of f i v e ques t ions , t h e f i r s t one served as a bu f f e r .

Thus, i n remaining four ques t ions , i f t h e l a r g e s t response

occurred a f t e r t h e re levan t ques t ion, a "2" was ass igned on

t h a t ques t ion, I f t h e second l a r g e s t response occurred af ter

t h e r e l evan t ques t ion , a "1" was ass igned on t h a t ques t ion,

I n o t h e r cases, "0" w a s assigned. Thus, with s i x r e p e t i t i o n s

of t h e series of ques t ions , a sum of 12 would s t rong ly

indicate guilt, while 0 would strongly indicate innocence.

For ana ly t i ca l purposes, those scoring 7 or more were

c l a s s i f i e d as g u i l t y , while those scoring less than 7 were

c l a s s i f i e d innocent. In the Delayed-Answer condition, t h i s

scoring procedure was applied separately t o the question-

elicited responses and answer-elicited responses.

Resu l t s

To assess d i f f e r e n c e s i n e lec t rodermal r espons iv i ty

among t h e f o u r d i f f e r e n t groups, t h e p a r t i c i p a n t s ' range-

co r r ec t ed SCRs t o s imple tone in t h e in i t i a l matching t r i a l

were compared. The t one -e l i c i t ed SCRs (ORs) were analyzed by

means of a 2 x 2 x 2 x 5 ( I n t e r v a l x Contingency x Sex x

T r i a l s ) mixed-design a n a l y s i s of variance (ANOVA) with

I n t e r v a l (immediate ve r sus de layed) , Contingency (con t ingen t

versus non-contingent) , and Sex (female ve r su s male) as

between-subject f a c t o r s , and Trials ( 5 t r ia ls ) as a within-

s u b j e c t f a c t o r . An a l pha l e v e l of - 0 5 was set f o r

statistical s i g n i f i c a n c e . Univar ia te tests for repeated

measures were a d j u s t e d for v i o l a t i o n of s p h e r i c i t y by us ing

the Greenhouse-Geisser ep s i l on c o r r e c t i o n procedure (Fowles,

C h r i s t i e , Edelberg, Grings, LykJcen, & Venables, 1981).

F igure 1 shows hab i t ua t i on curves t o f i v e tone s t i m u l i

i n the four d i f f e r e n t groups. The only s i g n i f i c a n t e f f e c t

was a T r i a l s effect, E ( 4 , 176) = 42.56, p < .0001 ( eps i l on =

. 7 4 2 ) , and t h e Sex main e f f e c t w a s n e a r l y s i g n i f i c a n t , E (1,

4 4 ) = 3.48, p = .069, Ms = . 43 and .33 for male and female,

r e spec t ive ly . These r e s u l t s i n d i c a t e t h a t t h e r e were no

d i f f e r ences in p a r t i c i p a n t s * e lec t rodermal r espons iv i ty

between groups, a t least i n response t o s imple tone s t i m u l i .

T h i s preexperimental equivalence among t h e condi t ions permi ts

f u r t h e r comparison of SCRs i n t h e d e t e c t i o n period among t h e

four groups wi thou t cons ide r ing i n i t i a l group d i f f e r ences i n

4 IAC

IANC - DAC - DANC - Average

1 2 3 4 5 Trials

Figure 1. Mean change in skin conductance response to simple tone during the matching trial in the Immediate- Answer-Contingent (IAC), Immediate-~nswer-Non-conthgent (IANC), Delayed-Answer-Independent (W), and Delayed- Answer-Non-contingent (DANC) groups.

responsivity prior to the introduction of the experimental

conditions.

Although it was not an essential purpose of the matching

trial, SCR changes were also compared among the five trials

by means of the Helmhert contrasts in order to see whether

complete habituation had occurred. The Helmhert contrasts

compared each trial mean of SCRs to the average of all

subsequent trial means with respect to trial order. When the

mean SCR amplitude of t h e t h i r d t r i a l was con t r a s t ed with t h e

averaged SCR amplitude of t h e four th and f i f t h t r ia l , t h e

s i g n i f i c a n t main e f f e c t of T r i a l s disappeared (E < 1 ) , which

suggest t h a t complete hab i tua t ion had occurred wi thin t h e

f i v e t r i a l s .

During t h e de t ec t ion period, each p a r t i c i p a n t had 6 SCRs

t o re levant quest ions and 18 SCRs t o n e u t r a l quest ions.

These responses were averaged to provide one mean SCR score

for re levant quest ions and one mean SCR score f o r neu t ra l

quest ions. I n addi t ion , t h e r e were a l s o 6 SCRs t o t h e tones

t h a t followed r e l evan t quest ions and 18 SCRs t o t h e tones

that followed n e u t r a l quest ions . These SCRs were a l s o

averaged t o provide one mean SCR score for each tone

stimulus.

Figure 2 shows t h e range-corrected mean SCR changes t o

quest ion onse t and fol lowing tone onset i n each group. These

data were analyzed by means of a 2 x 2 x 2 x 2 x 2 (Question

Type x I n t e r v a l x Contingency x Stimulus Type x Sex) mixed-

design ANOVA with Question Type ( re levant versus neu t r a l ) and

Stimulus Type (quest ion versus tone o n s e t ) as t h e within-

sub jec t f a c t o r s , and I n t e r v a l (immediate versus delayed),

Contingency (cont ingent versus non-contingent), and Sex

(female versus male) as t h e between-subject f a c t o r s . The

main e f f e c t of Question Type w a s s i g n i f i c a n t , E (I, 4 4 ) =

32.89, p < .0001 ( eps i lon = 1), with l a r g e r SCRs t o t h e

+ Relevant Question

IAC

+ Neutral Question

IANC DAC GROUP

DANC

Figure 2. Mean change in skin conductance response (SCR) to relevant and neutral questions during the detection period in the Immediate-Answer-Contingent ( I A C ) , Immediate- Answer-Non-contingent (IANC), Delayed-Answer-Contingent (DAC), and Delayed-Answer-Dependent (DANC) groups.

relevant questions than the neutral questions, which means

that a reliable GKT effect was obtained in the present

experiment, Ks = -39 and -32 for the relevant and neutral

questions, respectively. The main effect of Interval was

also significant, E (1, 44) = 8.17, < .01, indicating that

the two delayed-answer groups showed larger SCRs than the

immediate-answer groups, Ms = .31 and - 4 0 for the immediate-

and delayed-answer group, respectively. The Stimulus Type

main e f f e c t of was a l so s ign i f i can t , E (1, 4 4 ) = 30.72, p <

.0001 (eps i lon = l ) , indicat ing t h a t questions e l i c i t e d

l a rge r SCRs than tone s t imul i , = -42 and -28 f o r questions

and tone s t imul i , respectively. The tone s t imul i were

or ig ina l ly presented t o t h e delayed-answer groups t o prompt

t h e i r o r a l answers, b u t they were only dummy s t imul i for t h e

immediate-answer groups. Final ly , t h e main e f f e c t of

Contingency and Sex not only f a i l e d to reach signif icance (Es

(1, 4 4 ) = .05 and 1 . 5 2 f o r Contingency and Sex,

respec t ive ly) , but it a l s o d id not i n t e r a c t s ign i f i can t ly

with the o t h e r main factors , and, hence was excluded from t h e

following statistical analyses.

A three-way in te rac t ion among Questions Type x In te rva l

x Stimulus Type was s ign i f ican t , E (1, 4 4 ) = 8.16, g < .01.

From the po in t of t h e present experiment, it is important t o

examine t h e dif ference of t h e GKT e f f e c t between t h e

immediate- and delayed-answer condit ions, hence a 2 x 2

(Question Type x In te rva l ) mixed design ANOVA was conducted

a t question onset and a t tone stimulus onse t separately.

Figure 3 shows the range-corrected mean SCR changes t o t h e

question onse t ( l e f t panel) and t h e tone onset ( r i g h t panel) .

A t quest ion onset, t h e main e f f e c t of Question Type was

s ign i f i can t , E (1, 4 6 ) = 61.23, p < .0001 (epsilon = I),

indicat ing t h a t a r e l i a b l e GKT e f f e c t was obtained, Ms = .48

and .36 f o r the relevant and neu t ra l questions, respectively.

The main e f f e c t of In te rva l was also s ign i f i can t , E (1, 4 6 ) =

12.25, p < .001, indicat ing t h a t t h e immediate-answer

Immediate Delayed

Question onset

Immediate Delayed

Tone onset

Relevant Question

Neutral Question

Figure 3. Mean Change i n sk in conductance response (SCR) t o re levant and n e u t r a l quest ions a t t h e quest ion onse t (left panel) and a t t h e tone s t imulus onse t ( r i g h t panel) as a funct ion of immediate- and delayed-answer condi t ions .

condit ions elicited l a r g e r SCRs than t h e delayed-answer

condit ions, &i = - 5 0 and .34 f o r t h e immediate- and delayed-

answer condi t ion, respect ively . Moreover, a Question Type x

In t e rva l i n t e r a c t i o n was s i g n i f i c a n t , E (1, 4 6 ) = 6.50, <

.02, hence a comparison w a s made between t h e mean SCRs t o t h e

re levant and n e u t r a l quest ions for the immediate- and

delayed-answer condi t ions s epa ra t e ly using a paired &-test.

A s i g n i f i c a n t GKT effect--namely, t h e re levan t quest ions

e l i c i t e d l a r g e r SCRs than t h e n e u t r a l questions- w a s

obtained i n both t h e inanediate- and delayed-answer

condit ions, t ( 2 3 ) = 6 . 9 2 , p < .0001; L ( 2 3 ) = 3.99, p <

- 0 0 1 , r e spec t i ve ly . However, i n s p e c t i o n of Figure 2 sugges t s

t h a t t h e GKT e f f e c t i t s e l f is lager i n t h e immediate-answer

cond i t i on , and t h i s d i f f e r ence might c o n t r i b u t e t o t h e

s i g n i f i c a n t i n t e r a c t i o n . Thus t h e GKT effect w a s compared

between t h e inanediate- and delayed-answer condi t ions w i th a 2

sample L test. The r e s u l t showed t h a t t h e GKT e f f e c t in t h e

immediate-answer cond i t ion w a s s i g n i f i c a n t l y l a r g e r than t h a t

of t h e delayed-answer condi t ion , L (46) = 2.55, p < .02.

A t t o n e s t imulus onse t , on ly t h e main e f f e c t of I n t e r v a l

was s i g n i f i c a n t , E (1, 46) = 12.25, p < .001, i nd i ca t i ng t h a t

t h e SCRs were larger i n t h e delayed-answer condi t ion , &s =

.07 and - 4 6 for t h e immediate- and delayed-answer condi t ion .

S ince n e i t h e r t h e main e f f e c t of Ques t ion Type nor

i n t e r a c t i o n of Quest ion Type x I n t e r v a l was s i g n i f i c a n t , no

GKT effect was ob ta ined at t h e p o i n t of delayed answers.

The s c o r i n g method f o r f i e ld p r a c t i c e proposed by Lykken

(1959), described i n t h e Method s e c t i o n , y i e lded

c l a s s i f i c a t i o n of each p a r t i c i p a n t i n t o e i t h e r an "innocent"

o r a " g u i l t y " person, although, c l e a r l y , t h e p a r t i c i p a n t s i n

t h i s experiment were a l l belonged t o t h e " g u i l t y " category.

C l a s s i f i c a t i o n based on t h e immediate-answer response i n

t h e t w o immediate-answer cond i t ions w a s 66.7% (K = 16 )

correct; c l a s s i f i c a t i o n based on t h e response t o t h e ques t i on

o n s e t i n t h e t w o delayed-answer cond i t i ons was 41.7% (K = 1 0 )

correct; and c l a s s i f i c a t i o n based on t h e answer response i n

t h e two delayed-answer condit ions was only 29.2% (N = 7 )

co r r ec t . There w a s a s i g n i f i c a n t d i f f e r e n c e between t h e

accuracy rates of t h e immdiate- and delayed-answer

condi t ions when t h e latter was based on t h e answer response,

X2 (1, K = 4 8 ) = 7 . 3 5 , p < .01. However, when t h e accuracy

rate of t h e delayed-answer condit ion w a s based on t h e

response a t quest ion onset , there w a s no s i g n i f i c a n t

d i f f e rence between the immediate- and delayed-answer

condi t ion, X' (I, K = 4 8 ) = 3.02, g < -09.

to 0 0-

The p a r t i c i p a n t s i n t h e IAC and the DAC groups were

asked t o h i t a computer key a t t h e same t i m e they gave a

d e n i a l t o each quest ion t o g e t t h e nex t one on t h e computer

screen. Thus, f o r t h e s e pa r t i c ipan t s , it w a s possible to

measure response l a t ency t o t h e response cues, namely,

quest ion onset f o r t h e IAC group and tone onset f o r t h e DAC

group. However, t h i s measurement w a s no t e s s e n t i a l f o r t h e

experiment and a part of computer program t o measure t h e

r eac t ion time was incorporated a f t e r s e v e r a l pa r t i c ipan t s had

been already t e s t ed . Thus, only 2 1 p a r t i c i p a n t s ' data were

available (10 p a r t i c i p a n t s i n the IAC group and 11 i n t h e DAC

group). For each p a r t i c i p a n t , man r e a c t i o n t i m e was

obtained f o r r e l evan t and neutra l ques t ions , respect ively , by

averaging 6 responses t o t h e re levant and 18 responses t o t h e

n e u t r a l questions. These d a t a were incorporated i n t o a 2 x 2

(Group x Question Type) ANOVA. The on ly s i g n i f i c a n t e f f e c t

IAC Group DAC Group

Relevant Question

Neutral Question

Figure 4. Mean r e a c t i o n time t o t h e r e l evan t and neu t ra l questions i n t h e Immediate-Answer-Contingent and Delayed- Answer-Contingent groups.

was Group, E( 1 , l g ) = 6.66, p < -05 , i n d i c a t i n g t h a t react ion

time was s h o r t e r when pa r t i c ipan t s were tested i n the

immediate-answer condi t ion, Ms = 2.48 and 3.12 s for t h e

immediate- and delayed-answer condit ion, r e spec t ive ly (see

Figure 4 ) . The Question Type main e f f e c t w a s near ly

s i g n i f i c a n t , E (1, 19) = 4.12, p = .057 ( eps i lon = I), with

shorter r eac t ion times t o t h e re levant quest ions , Ks = 2.75

and 2.88 s f o r t h e r e l evan t and neu t r a l ques t ions ,

respect ively .

Discussion

The major finding of t h e f i r s t experinmnt is t h a t , with

a v i s u a l mode of presen ta t ion of t h e ques t ions , a r e l i a b l e

GKT e f f e c t in terms of SCR amplitude was obta ined i n both t h e

immediate- and delayed-answer condi t ion i n t h e i n t e r v a l

immediately fol lowing quest ion onset. Moreover, t h e

immediate-answer condi t ion produced a l a r g e r GKT e f f e c t than

t h e delayed-answer condi t ion a t quest ion onse t , whereas t h i s

was not c l e a r l y so when t h e c l a s s i f i c a t i o n index was applied.

I n t h e latter case, t h e accuracy rate of c l a s s i f y i n g

p a r t i c i p a n t s as g u i l t y did not d i f f e r s i g n i f i c a n t l y between

t h e immediate- and delayed-answer condi t ions . These r e s u l t s

thus , c o n t r a s t with t hose of Nakayam~ et al. (1988), who

reported not only t h a t t h e delayed-answer condi t ion w a s

super io r i n ob ta in ing t h e GKT e f f e c t , b u t also t h a t t h e

immediate-answer condi t ion f a i l e d t o yield any r e l i a b l e GKT

e f f e c t . A s previously noted, t h e GKT quest ions i n t h e immediate-

answer condi t ion i n t h e Nakayama e t a1.(1988), each remained

on t h e computer screen for a considerable t i m e a f t e r the

p a r t i c i p a n t s had given t h e i r answer t o it. It i s possible

t h a t , a s a r e s u l t of t h i s procedure, some of t h e pa r t i c ipan t s

i n t h e immediate-answer condit ion d id not treat t h e i r t a sk as

se r ious ly as the p a r t i c i p a n t s i n t h e delayed-answer

condit ion. The f a c t of t h e quest ions remaining on t h e screen

may look cont r ived or l ack sense t o t h e p a r t i c i p a n t s . To

i nves t iga t e t h i s poss ib le object ion or confound i n Nakayama

et a l . ' s study, t h e p re sen t experiment introduced an

a d d i t i o n a l immediate-answer condi t ion, where t h e quest ions

disappeared from t h e screen, as soon as t h e p a r t i c i p a n t s gave

t h e i r answers. I n o t h e r words, t h e disappearance of t h e

quest ions i n t h i s condi t ion was cont ingent upon t h e

p a r t i c i p a n t s ' answers, and, hence, more similar t o a normal

oral presen ta t ion of ques t ions than Nakayama e t a l e ' s

procedure. However, n e i t h e r t h e main e f f e c t of Contingency

nor i t s i n t e r a c t i o n wi th o t h e r main f a c t o r s w a s s i g n i f i c a n t .

The nons ign i f ican t Contingency main e f f e c t i n d i c a t e s t h a t t h e

o r i g i n a l purpose of t h e p re sen t experiment d i d n o t work as

expected, but, i n t u rn , it a l s o i n d i c a t e s t h a t t h e r e l i a b l e

GKT e f f e c t was obtained in t h e unmodified vers ion of t h e

immediate-answer condi t ion which was o r i g i n a l l y examined i n

Nakayarna e t a l . ' s study. Therefore, t h i s discrepancy between

t h e r e s u l t s of t h e two experiments i s p a r t i c u l a r l y d i f f i c u l t

t o expla in .

A conspicuous d i f f e r e n c e between t h e two is t h e

p a r t i c i p a n t s ' mot ivat ional l e v e l s t o avoid de tec t ion .

Nakayama e t a1 . , t h e p a r t i c i p a n t s were i n s t r u c t e d t h a t

electric shock would be d e l i v e r e d i f they f a i l e d t h e

polygraph test, and t o back up t h i s claim a real spark

f i r e d from a s tun gun as a demonstration, although t h e

was

i n s t r u c t i o n served only t o heighten t h e motivation of t h e

p a r t i c i p a n t s t o avoid de t ec t ion . I n t h e present experiment,

however, l o c a l e t h i c a l r e s t r i c t i o n s made it impossible t o

d u p l i c a t e t h i s p a r t of Nakayaxna et a l e ' s study and hence t h e

p a r t i c i p a n t s in t h e present s tudy -re only asked, i n a crime

scenar io , t o beat t h e polygraph test jus t i n order t o be

released from t h e po l i ce inves t iga t ion . Therefore, it could

be assumed t h a t t h e p a r t i c i p a n t s in t h e study of Nakayama e t

al. had higher l e v e l s of motivation than p a r t i c i p a n t s i n t h e

p resen t experiment.

Although severa l GKT s t u d i e s have manipulated l e v e l s of

motivation t o avoid de tec t ion , t h e r e s u l t s have been

d i sc repant . Elaad and Ben-Shakhar (1989) and Gustafson and

Orne (1963) found a b e t t e r rate of detect ion under

mot ivat ional i n s t ruc t ions to avoid detect ion, whi le Davidson

(1968), Furedy and Ben-Shakhar (1991), Horvath (1979) and

Lieb l ich , Naf t a l i , Shmueli, and Kugelmass ( 1 9 7 4 ) did not.

Moreover, when t h e e f f e c t of heightened motivation was

obtained (e.g., Elaad c Ben-Shakhar, 1989; Gustafson & Orne,

1963), it enhanced t h e d e t e c t i o n r a t e , not t h e reverse . The

p a r t i c i p a n t s i n Nakayama et al. may have used some kind of

countermeasures to avoid de tec t ion . In f a c t , Nakayama e t a l .

(1988) argued t h a t t h e SCRs obtained under t h e immediate-

answer condi t ion might have been contaminated by

p a r t i c i p a n t s ' motor responses (e.g., o r a l answers), and hence

t h i s produced i n f e r i o r de t ec t ion i n t h e immediate-answer

condit ion. However, as n e i t h e r Nakayama et al. nor t h e

presen t experimenter p e r f o m d any check on t h e use of

countermeasures by t h e p a r t i c i p a n t s , t h i s remains a matter of

pure specula t ion.

Severa l s t u d i e s have compared de t ec t i on e f f i c i ency

between t h e immediate- and delayed-answer condit ions.

However, t h e de t ec t i on d i d no t d i f fe r between t h e s e t w o

cond i t i ons when responses were compared immdia te ly following

ques t i on onse t in t h e CQT (Dawson, 1980), i n t h e GKT (Furedy

& Ben-Shakhar, 1991), and i n t h e i r DDP (Furedy, Davis, &

Gurevich, 1988). Only Furedy, Posner, and Vincent (1991)

found r e l a t i v e s u p e r i o r i t y o f t h e immediate-answer cond i t ion

t o d i f f e r e n t i a t e deception in t h e DDP experiment. The

delayed-answer condi t ion i n t h e p resen t s tudy a l s o y ie lded a

s i g n i f i c a n t d i sc r imina t ion between t h e re levan t and n e u t r a l

ques t ions when SCRs were compared following quest ion onset .

Moreover, the correct c l a s s i f i c a t i o n rates i n t h e two

cond i t i ons were not s i g n i f i c a n t l y d i f f e r e n t when t h e SCRs

w e r e compared following ques t ion onset . Accordingly, a t

least some of t h e discrepancy concerning t h e s u p e r i o r i t y of

t h e immediate-answer cond i t ion over t h e delayed-answer

cond i t i on may r e f l e c t nothing more than a sampling error. In

o t h e r w o r d s , g u i l t y knowledge can be de tec ted equal ly

s u c c e s s f u l l y i n t h e immediate- and delayed-answer cond i t ions

when t h e responses are compared immediately following

ques t i on onset . Since no d i sc r imina t ion e f f e c t w a s obta ined

f o r t h e p a r t i c i p a n t s ' answers i n t h e delayed-answer

cond i t ion , t h e crucial factor f o r t h e GKT e f f e c t may be t h e

i n t e n t i o n t o deceive r a t h e r t h a n t h e act of deception.

Although it w a s not an e s s e n t i a l ob j ec t i ve of t h e s tudy,

sex d i f f e r e n c e s i n the psychophysiological de tec t ion were

a l s o examined in t h e present experiment. In t h e initial

matching t r i a l , a marginally s i g n i f i c a n t sex d i f f e rence w a s

obtained wi th female p a r t i c i p a n t s showing smaller SCR-02s t o

t h e r e p e t i t i v e tone s t imul i . I n t h e de tec t ion period,

however, n e i t h e r t h e main effect of Sex nor i t s i n t e r a c t i o n

with o t h e r f a c t o r s were s i g n i f i c a n t . Several s t u d i e s of ORs

have ind ica ted t h a t females are less r e a c t i v e than males when

phasic electrodermal responses to simple s t imu l i are measured

( em+, K i m m e l & B i l l , 1961; K i m m e l 6 Kimmel, 1965; Maltzman,

Gould, Barnet t , Raskin, 6 Wolff, 1979), which is cons i s t en t

with t h e p resen t r e s u l t . Only a few s t u d i e s have examined a

poss ib le sex di f fe rences i n psychophysiological de t ec t ion

( e . g m , Cutrow e t a l . , 1972; Gudjonsson, 1982; Tinnn, 1982) but

they a l l agree t h a t sex i s unre la ted t o measures of

d i f f e r e n t i a l responsivi ty in t h e GKT. Sex d i f fe rences i n

SCRs, i f any, may be overridden by a t a s k like t h e GKT.

An i n t e r e s t i n g f ea tu re emerged in t h e r e s u l t s of t h e

r eac t ion the measure although t h i s was not planned as a

measure i n t h e present experiment. First, t he Delayed

Answer-Contingent (DAC) group showed a s i g n i f i c a n t l y l a r g e r

r eac t ion t i m e than t h e Immediate Answer-Contingent ( I A C )

group to both t h e re levant and n e u t r a l questions. As t h e DAC

group had 8 s t o process a ques t ion and prepare f o r t h e key

response, t h e reac t ion tin^ i n t h e DAC group ought to be

s h o r t e r compared to t h e IAC group. Second, reac t ion t i n e to

t h e re levant quest ions was s h o r t e r t han t o t h e n e u t r a l

ques t ions , a l though t h i s effect was on ly marginally

s i g n i f i c a n t . Davis (1961) suggested s e v e r a l hypotheses t o account f o r

augmented phys io log ica l responses i n t h e psychophysiological

d e t e c t i o n of deception. One of h i s hypotheses was t h a t t h e

r e l e v a n t ques t i on raises an e m t i o n a l c o n f l i c t in an examinee

because he or she should answer it decept ively , and such

c o n f l i c t produces a l a r g e r psychophysiological responses i n

t h e examinee. I f Davis ' s c o n f l i c t hypothesis is t r u e ,

r e a c t i o n time t o t h e re levan t ques t ion should be slower. The

p re sen t r e s u l t s , which showed a c c e l e r a t i o n of r e a c t i o n t i m e

t o t h e r e l e v a n t quest ion, apparen t ly con t r ad i c t t h e c o n f l i c t

hypothesis and hence need some cons idera t ions . However, t h e

r e s u l t would have t o be r e p l i c a t e d in another experiment f o r

f u r t h e r d i s cus s ion , as t h e d i f f e r e n c e i n reac t ion time t o t h e

r e l evan t and n e u t r a l ques t ion w a s on ly m g i n a l .

I n summary, t h e p resen t experiment showed t h a t g u i l t y

knowledge can be detected i n t h e immediate- and delayed-

answer cond i t i ons when t h e responses were compared

immediately fol lowing ques t ion onse t . Since t h e immediate-

answer c o n d i t i o n is easier t o deploy compared wi th t h e

delayed-answer condi t ion , t h e former procedure seems t o be

better i n f i e l d p r a c t i c e o f t h e GKT. There were no sex

d i f f e r e n c e s i n t h e GKT e f f e c t . F ina l l y , a r eac t i on t i m e

measure may provide add i t i ona l informat ion about t h e

mechanism of d i f f e r e n t i a l r e spons iv i t y t o re levan t and

n e u t r a l ques t i ons in t h e GKT.

EXPERIMENT I1

There are seve ra l t h e o r i e s t o account f o r t h e GKT

e f f e c t .

Lykken ( 1 9 7 4 ) , t h e o r i g i n a t o r of t h e GKT, conjectured

t h a t p r i o r knowledge of t h e r e l e v a n t items provides them w i t h

a " s i g n a l va luem t h a t c o n s t i t u t e s t h e b a s i s f o r d i f f e r e n t i a l

r e spons iv i t y t o t h e s e i t e m s . This assumption rests on t h e

theory of o r i en t ing responses (ORs ) . The OR descr ibes a

complex of physiological r e a c t i o n s evoked by a novel

s t imulus , change i n s t imulus modality, o r change i n stimulus

s i g n i f i c a n c e (e-g. , Berlyne, 1960; Lynn, 1966; Sokolov,

1 9 6 3 ) . Indeed, Lykken (1974) suggested, " . . . for the g u i l t y

only, t h e 'correct' a l t e r n a t i v e w i l l have a spec i a l

s i gn i f i cance , and added ' s i g n a l va lue ' which w i l l t end t o

produce s t ronge r o r i e n t i n g r e f l e x e s than t h a t sub j ec t w i l l

show to o t h e r a l t e r n a t i v e s " (p.728).

Ben-Shakhar (1977) elaborated Lykken's simple OR-based

explana t ion by including hab i tua t i on processes of ORs as an

important f a c t o r of t h e GKT e f f e c t and proposed

dichotomizat ion theory. According t o t h i s theory, ques t ions

(or i t ems) presented dur ing t h e GKT are d i f f e r e n t i a t e d

cogn i t i ve ly i n t o t w o d i s t i n c t ca tegor ies : r e levan t and

i r r e l e v a n t s t imul i . Furthermore, it i s assumed t h a t

hab i tua t i on takes place on ly wi th in each category wi th l i t t l e

o r no carryover across ca t ego r i e s . S ince t h e r e are fewer

r e l evan t ques t ions compared to i r r e l e v a n t or n e u t r a l

ques t ions i n t h e GKT, less hab i tua t i on occurs f o r r e l evan t

quest ions. I n o ther words, t h e GKT e f f e c t r e f l e c t s

d i f f e r ences in t h e amount o f hab i tua t ion occurring in t h e

r e l evan t and i r r e l e v a n t quest ion categor ies .

I n c o n t r a s t t o t h e OR-based approaches, earlier accounts

of psychophysiological de t ec t ion focused mainly on emotional

and motivat ional f ac to r s , such as c o n f l i c t accompanying ly ing

(Jung, 1906/1973; Luria, 1932), f e a r f u l consequences of

de t ec t ion (Davis, 1961), and/or motivat ion/intention to

deceive (Gustafson & Orne, 1963, 1965a). Although it i s

d i f f i c u l t t o c r e a t e s i t u a t i o n s i n laboratory experiments as

in t ense a s r e a l - l i f e polygraphic in te r roga t ions , t h e r e i s

experimental evidence t h a t emotional and motivat ional f a c t o r s

a f f e c t detect ion. For example, severa l laboratory s t u d i e s

have demonstrated t h a t p a r t i c i p a n t s who a r e motivated t o beat

t h e polygraph test are de tec ted a t a higher r a t e than

nomot iva ted pa r t i c ipan t s (e.g. , Gustafson & Orne, 1963,

1965a). As t o t h e c o n f l i c t hypothesis, severa l s t u d i e s have

repor ted f indings that o r a l responses of "no" t o t h e

quest ions, which can be opera t iona l ly defined as l y i n g and

expected to a r i s e c o n f l i c t i n a pa r t i c ipan t , produce a l a r g e r

GKT e f f e c t than "yes" o r a s i l e n t response (e.g., E l a a d &

Ben-Shakhar, 1989; Furedy & Ben-Shakhar, 1991; Gustafson &

Orne, 1965; Horneman & O'Gorman, 1985). Accordingly, it

seems d i f f i c u l t t o relate de t ec t ion of information t o a

single underlying mechanism, such as an emotional-

mot ivat ional mchanism o r a cogni t ive mechanism (Ben-Shakhar

& Furedy, 1990).

I n line wi th t h i s pe rspec t ive , E l a a d and Ben-Shakhar

(1989) have proposed a u n i f i e d conceptual framework t o

exp l a in t h e GKT effect. They suggested t h a t t h e response

evoked by t h e relevant i t e m o r ques t i on r e f l e c t s t h e degree

to which t h i s s t imu lus was a t t ended t o . Detect ion can be

avoided i f t h e p a r t i c i p a n t manages t o ignore t h e r e l evan t

i t e m s . However, do ing t h i s is n o t an ea sy t a s k because

various f a c t o r s , such as t h e n a t u r e of t h e r e l evan t s t imulus

and t h e mot iva t iona l state of t h e p a r t i c i p a n t , may ope ra t e t o

keep t h e focus of a t t e n t i o n upon t h e r e l e v a n t i t e m s . Elaad

and Ben-Shakhar (1989) used t h e term "noteworthiness" o f t h e

s t imulus to denote t h e degree of a t t e n t i o n elicited by t h a t

s t imulus . According t o t h e pe rspec t ive , factors such a s motivat ion

and type of v e r b a l response affect d e t e c t i o n through t h e i r

in f luence on t h e noteworthiness of t h e r e l e v a n t items. For

example, when t h e consequence of t h e d e t e c t i o n test is

important for t h e p a r t i c i p a n t , it becomes more d i f f i c u l t t o

i gno re t h e r e l e v a n t i t e m . Likewise, a decep t ive answer t o a

r e l e v a n t i t e m may i n c r e a s e i t s noteworthiness because of t h e

p a r t i c i p a n t ' s c o n f l i c t i n t h a t s i t u a t i o n . Elaad and Ben-

Shakhar (1989) v a r i e d t h e mot iva t iona l f a c t o r (h igh and low

motivat ion t o beat t h e polygraph test) and t h e ve rba l

response t ype ("no," "yes," s i l e n t , and r epea t i ng i t e m ) i n

t h e i r exper inent . They p red i c t ed t h a t a higher de t ec t i on

rate would be ob t a ined i n t h e heightened motivat ion group

t h a n i n t h e low nmtivat ion group because motivat ion might

increase t h e noteworthiness of t h e r e l evan t s t imulus, and

thus would make it wre d i f f i c u l t t o ignore* As t o the

verbal response type, t h e demand f o r a verba l response might

be assoc ia ted wi th more a t t e n t i o n directed t o t h e re levant

stimulus than remaining s i l e n t , which allows a s t ra tegy of

ignoring t h a t stimulus; thus , a higher de t ec t ion r a t e would

be obtained i n t h e verbal response groups than in the s i l e n t

group. Furthermore, a va r i ab le ve rba l response ( repeat ing

i t e m s ) t o t h e d i f f e r e n t s t i m u l i might r equ i r e more a t t en t ion

than a s tandard response t o a l l s t imu l i . Thus, t h e highest

de tec t ion rate would be obtained i n t h e heightened motivation

w i t h v a r i a b l e ve rba l response group.

The r e s u l t s indicated t h a t h ighly motivated pa r t i c ipan t s

were detected a t a higher rate than less motivated

pa r t i c ipan t s . The act of lying was assoc ia ted with enhanced

d i f f e r e n t i a l responsivi ty , but no d i f f e rences were obtained

between ve rba l response versus no response o r between

va r i ab le versus standard verbal response. Elaad and Ben-

Shakhar (1989) concluded t h a t t h e r e s u l t s only p a r t i a l l y

supported t h e noteworthiness hypothesis, because they f a i l e d

t o demonstrate predic ted d i f f e rences between verba l

responding ve r sus remaining s i l e n t and between var iable

versus s tandard verbal response, However, it is possible

t h a t t h e noteworthiness of r e l evan t items in t h e i r study was

so s t rong it i n h i b i t e d t h e e f f e c t of a demanding verbal

response, t h a t i s t o say, a " c e i l i n g e f f e c t . "

On t h e b a s i s of t h e noteworthiness explanat ion, it is

predic ted t h a t i f an experimental manipulation can produce

c l e a r l y d i f f e r e n t s i g n a l values f o r each r e l evan t i t e m , t h e

magnitude of psychophysiological response t o each relevant

i t e m w i l l vary wi th s i g n a l value. The presen t experiment was

designed t o e v a l u a t e t h i s hypothesis.

F i r s t , t w o groups of p a r t i c i p a n t s were asked t o choose

two items r e l a t i n g to an imagined-crime s i t u a t i o n (burg la ry )

i n a crime scenar io , each from a d i f f e r e n t category (spot f o r

invasion and i t e m t o steal). These t w o items comprised t h e

t w o r e l evan t items of t h e GKT which w e r e given later. One

group of p a r t i c i p a n t s were presented an alarm sound from t h e

computer when t h e y chose t h e i t e m t h e y imagined s t e a l i n g .

This procedure was designed t o add some r e a l i t y t o a cr ime

scenar io and a rouse p a r t i c i p a n t s ' emotions. Therefore, t h e

procedure enhanced t h e s i g n a l va lue of i tems accompanied by

an alarm. It w a s expected t h a t both of t h e re levan t i tems

would produce enhanced SCRs i n t h e GKT, bu t t h a t t h e i t e m of

heightened s i g n a l va lue would evoke a l a r g e r e lec t rodermal

response than t h e normal re levan t i t e m .

To a s se s s t h e OR-based accounts of t h e GKT e f f e c t , t h e

p a r t i c i p a n t s were a l s o t o be exposed t o t h e Prel iminary

Novelty Paradigm (PNP) prior t o the GKT procedure. This

procedure is designed t o measure i nd iv idua l d i f f e r ences wi th

r e spec t t o some key c h a r a c t e r i s t i c s of t h e OR (Furedy,

1993b). B r i e f l y , t he PNP c o n s i s t s o f 9 repeated tone (or

light) trials, fol lowed by a cross-modal changed l i g h t (or

t one ) , and a re-presenta t ion of t h e repeated tone ( o r l i g h t )

stimulus. With t h e PNP, four well-known components of OR can

be assessed: namely, habi tuat ion ( t r i a l 1 minus t r i a l 9 ) ,

d i shab i tua t ion ( t r i a l 11 rainus t r ia l 9 ) , OR reinstatement or

ORR ( t r i a l 10 minus t r i a l 9 ) , and super ORR ( t r ia l 10 minus

t r i a l 1). A l l t h e s e four e f f e c t s were expected t o energe

r e l i a b l y i n t h e sense t h a t t h e first term i n t h e four

equations exceeds t h e second term (see, e-g. , Furedy, 1968;

Ginsberg & Furedy, 1974). However, t h e c r i t i c a l assessment

f o r t h e p re sen t experiment cons i s t ed i n examining t h e

c o r r e l a t i o n s between these four O R - r e l a t e d e f f e c t s and t h e

GKT e f f e c t . I f an OR mechanism is s i g n i f i c a n t l y involved i n

t h e GKT, a l l f o u r OR components should be co r r e l a t ed with t h e

GKT e f f e c t .

Another d i s t i n c t i v e aspect of t h e p resen t experiment was

introducing a voice-synthesized i n t e r r o g a t i o n by computer and

assess ing its e f f i cacy . Since most polygraphers know the

f e a t u r e of the crime i n quest ion, t h i s may lead t o t h e i r

d i f f e r e n t i a l l y present ing t h e r e l evan t and cont ro l quest ions .

I n add i t ion , t h e polygrapher must i n t e r a c t w i t h a suspect

before and during t h e de tec t ion test, and t h i s could create a

prejudice about t h e guilt of t h e suspect . The voice-

synthesized presen ta t ion by computer e l imina tes t h i s source

of poss ib le examiner b ias and, e s s e n t i a l l y , sets up a "bl ind"

i n t e r roga t ion

Design of Exper inent 11

A 2 x 2 x 2 (Quest ion Type x Category x Signal Value)

mixed des ign w i t h repeated measures on Quest ion Type and

Category was used. The Question Type v a r i a b l e refers t o the

r e l e v a n t and n e u t r a l quest ions: t h e v a r i a b l e the most

cr i t ical in t h e GKT study. The Category v a r i a b l e refers t o

the s p o t for invas ion and i t e m t o steal. A between-subjects

factor w a s the l e v e l s of s i g n a l v a l u e of r e l evan t i t ems

varied by t h e alarm t reatment . The t rea tment w a s also va r i ed

as a wi th in -sub jec t s factor; p rov id ing t h e alarm t r ea tment

only to t h e s t o l e n i t e m i n t h e exper imenta l group. Reaction

time was inc luded as a dependent variable besides SCR,

because it provided i n s i g h t f u l in fo rmat ion i n Experiment I

which c o n t r a d i c t e d t h e c o n f l i c t exp lana t ion of t h e GKT

effect.

Method

Sixty-four par t ic ipants ( 3 7 females and 27 males, aged

19-51) were randomly divided i n t o t w o groups. A majori ty of

pa r t i c ipan t s (H = 51) were r ec ru i t ed from t h e Introductory

Psychology class a t t h e Universi ty of Toronto f o r course

credit and t h e remaining minority (N = 13) was recru i ted

through pos te r s on campus. The latter, predominantly

univers i ty s tudents , were paid $8.00 f o r t h e i r par t ic ipa t ion .

None of t h e par t ic ipants had previously taken p a r t in any

type of s t u d i e s of detection of deception.

mPa--=

The p a r t i c i p a n t s were tested i n t h e same room with t h e

same SCR recording equipment a s i n Experiment I, except a

computer (Primax-320SX, IBM PC compatible) with a 15 inch

monitor and two outside speakers. The computer was equipped

w i t h a Sound B l a s t e r pro@ card (Creative Technology, Model

CT-1330), which enabled del ivery of t h e interrogat ive

questions in auditory mode by computer-synthesized voice

during t h e de tec t ion phase. Its text-to-speech function was

control led by a software, ~onologue@ ( F i r s t Byte ) , which was

act ivated by t h e main program wr i t t en i n Microsoft Quick

Basic 4.5@. The computer synthesized a male voice del ivered

a t a speed of around 350 m s per word. All t h e in te r rogat ive

questions t h a t t h e computer provided o r a l l y and were used i n

the de tec t ion phase were checked and reviewed p r i o r to t h e

experiment by f i v e persons whose f i r s t and predominant

language was English. A l l t h e ques t i ons were w r i t t e n and

s p e l l e d c o r r e c t l y without d i f f i c u l t y by t h e reviewers, which

w a s cons idered t o demonstrate s a t i s f a c t o r y phonic q u a l i t y of

the ques t ions . To measure p a r t i c i p a n t s ' r eac t ion t i m e t o

each ques t i on i n 1 m s order , TIMERSET and TMRREAD subrout ines

(Graves c Bradley, 1987, 1988) were incorporated i n t o t h e

main program t h a t con t ro l l ed t h e sequence of t h e experiment.

The computer was also used to g i v e i n s t r u c t i o n s about t h e

experiment i n a v i s u a l mode.

The P r e l i m i n a r y Novelty Paradigm (PNP) w a s carried o u t

prior t o the main experimental procedure. The PNP cons i s t ed

o f 9 repeated tone (or l i g h t ) trials, followed by a cross-

modal change l i g h t (or tone) t r ial , and a re-presenta t ion of

the repeated s t imulus tone (or l i g h t ) . The l i g h t was

provided by a 100 w bulb which was mounted on t h e w a l l of t h e

room, above and t o t h e r i g h t of the pa r t i c ipan t . The tone

w a s 1 kHz, 80 dB at t h e source and about 70 dB a t t h e

p a r t i c i p a n t s ' level, coming thorough a loud speaker placed

ad jacen t to t h e l i g h t source. The dura t ion of t h e t one and

l i g h t was 800 m s , while t h e in ter -s t imulus i n t e r v a l w a s

randomly v a r i e d between 25, 30 (mean), and 35 s. The

p r e s e n t a t i o n of t h e s e s t i m u l i w a s con t ro l l ed by means of a

four channel t a p e recorder (SONY TC-854-4) with four t apes

having been pre-programmed f o r t h a t purpose with an i n t e r -

s t imulus - in te rva l i d e n t i c a l t o t h e above. The presen ta t ion

of the t one and l i g h t was counterbalanced i n both groups.

Continuous whi te no i s e of 70 dB a t its source and about 60 dB

a t t h e p a r t i c i p a n t s * l e v e l served t o reduce any possible

extraneous sounds dur ing t h e PNP.

Procedure

When t h e p a r t i c i p a n t s a r r ived for t h e experiumnt, they

w e r e greeted by t h e e x p e r h n t e r and given general

information concerning t h e nature of t h e experiment. They

were t o l d t h a t t h e purpose of t h e e x p e r h n t w a s t o examine

t h e r e l i a b i l i t y of a computer-assisted de t ec t ion of deception

(lie d e t e c t i o n ) and t h e i r t a s k was, i n an imagined crime

s i t u a t i o n , to play t h e r o l e of a bu rg la r who faced a

polygraph test and tried to beat it i n order to be released

from t h e p o l i c e department. The p a r t i c i p a n t s were a l so t o l d

t h a t t w o e l e c t r o d e s would be a t tached t o t h e i r l e f t hands

before s t a r t i n g t h e experiment b u t t h a t they were only

recording e l e c t r o d e s and they would n o t experience any

discomfort f r o m t h e e lect rodes . F ina l ly , t h e pa r t i c ipan t s

w e r e t o l d t h a t t h e experiment i t s e l f , t h a t is a p a r t from

preparat ions and in s t ruc t ions , would last for approximately

40 minutes.

Following t h e general explanat ions of t h e experiment,

each p a r t i c i p a n t s igned an informed consent form which stated

t h a t t h e p a r t i c i p a n t w a s aware of t h e na ture of t h e

experiment and t h a t he o r s h e could te rmina te t h e experiment

a t any time w i t h impunity.

The p a r t i c i p a n t s were then led into a room described as

t h e " in t e r roga t ion room," adjoining t h e one used for t h e

physiological recording by t h e experimenter. The

p a r t i c i p a n t s were sea t ed a t a table f a c i n g t h e computer and

then e l e c t r o d e s were a t t ached f o r SCR measurement. Once t h e

e l ec t rodes were in place , t h e p a r t i c i p a n t s were asked to rest

t h e l e f t hand on a soft pad and t o keep it sti l l and avoid

unnecessary movements,

A f t e r t h e completion of t h e at tachment of t h e

e l ec t rodes , t h e p a r t i c i p a n t s were told t h a t detailed

i n s t r u c t i o n s for t h e experiment and the d e s c r i p t i o n of t h e

crime, f o r which t h e p a r t i c i p a n t s had t o undergo a polygraph

i n t e r roga t i on , would be given on the computer screen i n

w r i t t e n form and asked to i n i t i a t e t h e computer program by

hitting any key on t h e computer once t hey were ready. On t h e

bottom l i n e of the screen, a note prompted t h e p a r t i c i p a n t s

t o advance to t h e nex t screen by h i t t i n g any key so t h a t t h e y

could read t h e i n s t r u c t i o n s a t t h e i r own pace (see Appendix B

f o r t h e e x a c t i n s t r u c t i o n s presented on t h e computer sc reen) .

On t h e first screen, each p a r t i c i p a n t was instructed

t h a t t h e experiment had three segments, namely, a ba se l i ne

period, r e ad ing a crime scenar io , and a l ie de t ec t i on test.

On t h e next s c r een , i n s t r u c t i o n abou t t h e ba se l i ne period was

provided. The p a r t i c i p a n t s were told t h a t they would r ece ive

s eve ra l t ones or l i g h t s f o r t h e 5 min b a s e l i n e per iod and

asked not t o move t h e i r f i n g e r s w i t h t h e e l ec t rodes t o o much.

I f t h e p a r t i c i p a n t s understood t h e i n s t r u c t i o n s and agreed t o

start t h e b a s e l i n e period, t h e experimenter turned o f f t h e

computer s c r e e n and l e f t t h e " i n t e r r o g a t i o n room" and went

i n t o t h e adjoining room, Once t h e polygraph was calibrated,

SCR recording and t h e PNP were initiated. The first tone or

l i g h t s t imulus was p r e s e n t e d approximately after 2 min from

t h e o n s e t of t h e recording. H a l f of t h e p a r t i c i p a n t s

rece ived t h e t o n e s t i m u l u s and t h e o t h e r h a l f t h e l i g h t

s t imulus d u r i n g t h i s phase.

After t h e b a s e l i n e pe r iod was completed, t h e

experimenter r e t u r n e d t o t h e " i n t e r r o g a t i o n room" and turned

on t h e computer sc reen . When t h e experimenter h i t a key, t h e

next i n s t r u c t i o n appeared. On t h e computer, it was explained

t o t h e p a r t i c i p a n t s t h a t t h e y were being asked t o play t h e

role of a b u r g l a r and later they would be reques ted in a

crime s c e n a r i o t o choose one s p o t where t h e y would have

broken i n t o a house and one item they would have s t o l e n . On

t h e s e chosen items, t h e y would t a k e a l i e d e t e c t i o n test

because t h e r e was n o t enough material evidence for a

convic t ion . They were f u r t h e r t o l d t h a t t h e y should try t o

be a good l i a r d u r i n g t h e d e t e c t i o n phase and try no t t o

r e v e a l t h e chosen i t e m s in t h e i r phys io log ica l responding.

Then a demonst ra t ion of t h e synthes ized v o i c e was run i n

a d d i t i o n t o a v i s u a l mode p r e s e n t a t i o n of t h e ques t ion , "Did

you steal t h e radio?" It was explained on the computer

sc reen t h a t t h e p a r t i c i p a n t s would go through a p r a c t i c e

s e s s i o n where t h e y deny every ques t ion o r a l l y by say ing "no"

and s imul taneous ly h i t t h e space bar on t h e computer

keyboard. Four q u e s t i o n s were presented d u r i n g t h e p r a c t i c e

sess ion; t h e y were t h e n repea ted i f t h e p a r t i c i p a n t f a i l e d t o

respond t o t h e l a s t three p rac t i ce quest ions i n an average

time of less than 100 m s or longer than 1000 m s .

After successful completion of t h e p r a c t i c e session, the

experimenter re turned t o t h e experimenter 's room and t h e

p a r t i c i p a n t s were then given t h e crime scenar io by h i t t i n g a

computer key by themselves. In t h e scenar io , t h e

p a r t i c i p a n t s were asked t o choose one of f i v e spots t o break

i n as w e l l a s one of f i v e items t h a t they could steal, by

r e f e r r i n g t o t w o s h e e t s which depic ted a house layout and

items (Appendix A-1, 2 ) , respect ively . The f i v e a l t e r n a t i v e s

f o r t h e spot were "1) Entry," " 2 ) Family room," "3) Garage,"

" 4 ) Kitchen, " and "5) Living room, " and f o r t h e items were

"1) Bracelet," "2) Camera," " 3 ) Purse," " 4 ) Ring," and "5)

Watch." The p a r t i c i p a n t s were requested t o type t h e number

key on t h e computer keyboatd which corresponded t o t h e

selected a l t e rna t ives . Immediately a f t e r t h e pa r t i c ipan t s in

t h e experimental group, but not i n t h e con t ro l group, typed

i n t h e number of s e l ec t ed i t e m , t h e alarm sound went off from

t h e computer's two ou t s ide speakers. The alarm was 80 dB a t

t h e pa r t i c ipan t s ' l e v e l and composed of 1.2 kHz and 1 kHz

sound provided a l t e r n a t i v e l y a t t h e dura t ion of 800 m s each.

The alarm could be terminated once t h e pa r t i c ipan t h i t any

key on t h e computer keyboard a s directed on t h e next computer

sc reen which appeared when t h e alarm went o f f . Thus, t h e

i n s t r u c t i o n s were d i f f e r e n t only in t h i s p a r t of t h e crime

scenario between the e x p e r i m n t a l and con t ro l groups. On the

final screen of t h e scenario, t h e p a r t i c i p a n t s were reminded

of t h e spo t and i t e m they had chosen. It was explained on

the computer sc reen t h a t t h e i n t e r r o g a t i o n was about t o begin

and t h a t t h e p a r t i c i p a n t s had t o deny every question and h i t

t h e space bar on t h e computer keyboard a t t h e same t i m e . The

computer also gave i n s t r u c t i o n s t o h i t t h e space bar t o

i n i t i a t e t h e in t e r roga t ion once t h e p a r t i c i p a n t s were ready.

When they h i t t h e bar, t h e computer sc reen went blank and t h e

f i r s t i n t e r r o g a t i v e quest ion was presented a f t e r 5 s had

elapsed.

I n t h e de t ec t ion period, each ques t ion was presented

o r a l l y by t h e computer synthesized voice as described above.

The ques t ions about t h e burglar ized spo t and s to l en i t e m were

presented i n the following way: "Did you break i n through t h e

entry?" with t h e spo t being changed appropr ia te ly with t h e

f i v e a l t e r n a t i v e spo t s and "Did you steal t h e bracele t?" wi th

t h e i t e m being changed appropr ia te ly wi th t h e f i v e

a l t e r n a t i v e items. One series of ques t ions w a s constructed

e i t h e r f r o m t h e f i v e spots o r f i v e items and each series was

repeated fou r times a l t e r n a t i v e l y . Half t h e pa r t i c ipan t s

received ques t ions on t h e spo t f i r s t and t h e o the r half

received ques t ions on t h e i t e m f i r s t . The questions in t h e

series were presented a t a fixed i n t e r v a l of 20 s and with 40

s pause between each series. The ques t ions on each i t e m were

presented a t random i n each series wi th t h e r e s t r i c t i o n t h a t

t h e f i r s t ques t ion i n each series would not be t h e re levant

a l t e r n a t i v e ; t h u s t h e f i r s t ques t ion i n each series w a s

treated a s a b u f f e r and w a s excluded from t h e data ana lys i s .

A follow-up telephone interview was carried out after

approximately a month l a t e r without pa r t i c ipan t s ' p r i o r

notice. I n t h e interview, the par t i c ipan t s were asked which

spot and i t e m they had chosen i n t h e experiment. The

pa r t i c ipan t s i n t h e experimental group were a l s o asked to

describe t h e i r feeling when t h e alarm had sounded a f t e r

se l ec t ing an i t e m by choosing one of t h e following

a l t e rna t ives : a) startled, b) alarmed, c) aroused, d )

in t e res t ed , and e ) nothing.

Finally, 6 par t ic ipants chose Entry, 7 par t ic ipants

chose Family room, 23 chose Garage, 2 3 chose Kitchen and t h e

remaining 5 par t ic ipants chose Living room a s an invasion

spot. As a s t o l e n item, 10 pa r t i c ipan t s chose Bracelet, 16

chose Camera, 5 chose Purse, 20 chose Ring and t h e remaining

13 p a r t i c i p a n t s chose Watch. - The SCRs were defined and scored i n t h e same way as i n

t h e Experiment I. For s t a t i s t i c a l purpose, however, t h e

square root transformation f o r SCR amplitudes (Grings, 1 9 7 4 )

was used to improve t h e SCR's d i s t r i b u t i o n cha rac te r i s t i c s

ins tead of t h e range correct ion method (c f . Lykken, 1972)

used i n Experiment I. This was due t o t h e d i f f e ren t

manipulations f o r the experimental and control groups i n t h e

present experiment, where only t h e experimental pa r t i c ipan t s

received t h e alarm sound when they had chosen an item and t h e

sound evoked t h e l a rges t response i n most of t h e experimental

pa r t i c ipan t s . I n t h i s case, t h e range correction method

would lead t o smaller scores in t h e experimental p a r t i c i p a n t s

because it d i v i d e s every score ob ta ined by a single

p a r t i c i p a n t w i t h t h e maximum score obta ined by t h a t

p a r t i c i p a n t du r ing t h e experiment. The square root

t ransformat ion was chosen because it is t h e one t h a t has been

mostly app l i ed t o SCR amplitudes (cf. Boucsein, 1992) .

Another dependent va r i ab l e was r e a c t i o n t i m e t o each

quest ion o f f s e t and t h i s was measured by making p a r t i c i p a n t s

h i t a computer key simultaneously when t hey give t h e i r o r a l

answers. A computer clock gave 1 ms o r d e r accuracy of

elapsed t ime .

P a r t i c i p a n t s were c l a s s i f i e d as g u i l t y o r innocent by

Lykken's (1959) method as i n t h e Experiment I, except t h a t

t he g u i l t y score was set t o 9 o r more because t h e r e were a

t o t a l of 8 r e p e t i t i o n s o f series of ques t ions .

Results

f P m

Figure 5 shows mean elec t rodermal responses during t h e

Preliminary Novelty Paradigm (PNP ) for t h e experimental and

c o n t r o l groups. To assess d i f f e r ences i n e lec t rodermal

r e spons iv i t y t o simple s t i m u l i between t w o groups, t h e i r SCRs

du r ing t h e PNP were analyzed by means of a 2 x 11 (Group x

T r i a l s ) ANOVA with r epea t ed measures on trials. Only t h e

T r i a l s main e f f e c t was s i g n i f i c a n t , E (1, 10) = 21.92, p <

-0001 ( ep s i l on = .818), i nd i ca t i ng absence of group . d i f f e r e n c e i n e l e c t rode rma l r espons iv i ty , a t least i n SCRs t o

s imple tone o r l i g h t s t i m u l i .

With t h e s t imu lus p a t t e r n used i n t h e PNP, t h e f ou r

novelty e f f e c t s , namely, habi tua t ion , d i shab i t ua t i on , OR

re ins ta tement or ORR, and super ORR effects, should be

observed on SCRs d u r i n g t h e PNP ( e -g . , Furedy, 1968, 1993b;

Ginsberg & Furedy, 1974). To test t h e s i g n i f i c a n c e of t h e s e

f o u r novel ty e f f e c t s , SCRs between T r i a l 1 (K = - 5 4 ) and

T r i a l 9 (M = -20) were compared f o r hab i t ua t i on , Trial 11 (K

= -31) and T r i a l 9 for d i shab i tua t ion , T r i a l 10 ( M = - 6 6 ) and

T r i a l 9 f o r ORR, and T r i a l 9 and T r i a l 1 f o r super O M e f f e c t

by us ing a 2 x 2 (Group x T r i a l ) ANOVA with repeated measures

on t r i a l s , A l l t h e s e e f f e c t s were r e l i a b l y shown i n t h e

s ense that t h e former t r i a l i n each effect described above

was s i g n i f i c a n t l y l a r g e r than t h e latter tr ial : habi tua t ion

effect, E (1, 62) = 61.78, p < .0001; d i shab i t ua t i on effect,

+ Experimental Group

+ Control Group

w

Figure 5. Mean change i n sk in conductance response (SCR) dur ing t h e Preliminary Novelty Paradigm.

E (1, 6 2 ) = 7.36, p < * O O l ; ORR, E (1, 62) = 114.42, <

.0001; and super O m , E (1, 6 2 ) = 12.97, p < .001. However,

n e i t h e r Group effect nor t h e Group x T r i a l i n t e r a c t i o n was

s i g n i f i c a n t , i n d i c a t i n g again t h a t both t h e experimental and

c o n t r o l groups did n o t d i f fe r i n terms of o r i e n t i n g

responses.

Gr-

Only t h e exper imenta l p a r t i c i p a n t s r ece ived t h e alarm

sound when t hey selected an i t e m dur ing t h e s cena r io reading.

This was carried out i n t h e hope of adding a s i g n a l value

onto t h e i t e m which t h e experimental p a r t i c i p a n t s had

selected. To check whether t h e manipulat ion caused a

r e l i a b l y l a r g e r r e a c t i o n , SCRs which were initiated wi th in 1

t o 5 s a f t e r t h e spot and i t e m selections were compared. As

is shown i n F i g u r e 6, t h e alarm provided t o t h e p a r t i c i p a n t s

o f t h e exper imen ta l group caused t h e largest SCRs. A 2 x 2

(Group x Category) ANOVA w i t h repeated measures on c a t e g o r i e s

was conducted on t h e s e SCR scores. Main e f f e c t s of Group, E

(1, 62) = 16.47, Ms = 1.23 and .84 for t h e experimental and

c o n t r o l group, r e s p e c t i v e l y ; Category, E (1, 62) = 38.68, Lls

= .87 and 1.20 for t h e s p o t and i t e m category, respec t ive ly ;

and Group x Category i n t e r a c t i o n , E (1, 62 ) = 35.63, were a l l

s i g n i f i c a n t (p < .0001). Subsequent comparison revea led t h a t

SCRs a f t e r i t e m selection by t h e exper imen ta l p a r t i c i p a n t s

were s i g n i f i c a n t l y larger t h a n SCRs a f t e r spot s e l e c t i o n by

t h e s a m group, k (31) = 5.91, p < .0001, = 1.56 and - 9 0

for t h e i t e m and s p o t s e l e c t i o n , r e s p e c t i v e l y . The SCRs were

also s i g n i f i c a n t l y l a r g e r t h a n t h e SCRs t h e c o n t r o l group

e x h i b i t e d a f t e r spot s e l e c t i o n (K = .83), t (62) = 6.19, p <

.0001, and i t e m s e l e c t i o n (K = . 8 4 ) , L ( 6 2 ) = 5.28, p <

.0001. The o t h e r combinat ions of comparison d i d not reveal

any s i g n i f i c a n t d i f f e r e n c e .

Because of t h e confound p o s s i b i l i t y t h a t t h e alarm

sound, pp- c o u l d have produced an emot ional e f f e c t , a

follow-up t e l e p h o n e i n t e r v i e w was conducted approximately a

month later w i t h o u t t h e p a r t i c i p a n t s ' p r i o r n o t i c e . I n t h e

f i r s t phase of t h e i n t e r v i e w , t h e p a r t i c i p a n t s were requested

t o i d e n t i f y which spot and i t e m t h e y had s e l e c t e d i n t h e

0 spot !

Item

Experimental Control Group

Figure 6. Mean amplitude i n sk in conductance response observed i n t h e experimental and con t ro l groups when t h e p a r t i c i p a n t s selected a spo t and an i t e m dur ing t h e scenar io reading. The alarm was provided on ly f o r t h e experimental p a r t i c i p a n t s when they selected an i t e m .

experiment. A t o t a l of 54 pa r t i c ipan t s could be reached.

The accuracy of t h e memory of t h e i r own s e l e c t i o n is

summarized i n Table 1. There was no s i g n i f i c a n t d i f ference

between t h e groups in terms of t h e proport ion of those who

gave c o r r e c t and i n c o r r e c t answers f o r t h e s p o t se lec t ion , XZ

(1, K = 5 4 ) = .43, p > .I, and f o r t h e i t e m s e l ec t i on , X 2 (1,

K = 54 ) = 1.03, p > .I. This i nd i ca t e s tha t t h e alarm sound,

which w a s presented on ly t o t h e experimental group, did not

a f f e c t memorial r e t e n t i o n of t h e selected items.

Table 1.

N u m b e r of pa r t i c ipan t s who cor rec t ly o r incor rec t ly iden t i f i ed t h e i r own c r i t i c a l items during t h e telephone interview

SDat Item EXP Cont. Total Exp . Cont. Total

Correct 23 2 3 46 2 1 22 43 Incorrect 3 5 8 5 6 11

The pa r t i c ipan t s in t h e e x p e r h n t a l group were fur ther

asked t o describe t h e i r feel ings when they had heard t h e

alarm sound immdiately a f t e r t h e i r i t e m se l ec t ion by

choosing one of t h e following a l te rna t ives : a ) s t a r t l e d , b)

alarmed, c ) aroused, d ) in te res ted , and e) nothing. m n t y

six out of 32 pa r t i c ipan t s could be reached. Fourteen

par t ic ipants chose " s t a r t l e d , " 4 pa r t i c ipan t s chose

"alarmed," 1 p a r t i c i p a n t chose "aroused," 3 par t ic ipants

chose " interested," and remaining 4 pa r t i c ipan t s chose

"nothing." The r e s u l t ind ica tes t h a t t h e alarm sound caused

some emotional reac t ion i n t h e experimental par t ic ipants

s ince only 4 pa r t i c ipan t s chose "nothing" ( p < .0001,

binomial test ) .

During the de tec t ion period, each p a r t i c i p a n t

accumulated 4 SCRs t o re levant questions and 1 2 SCRs t o

neut ra l questions for each spot and i t e m category. These

responses were averaged t o provide one mean SCR score f o r

re levant questions and one mean SCR score f o r neutral

questions f o r each spot and i t e m category. These data were

Experimental Group

Control Group

~elevant Neutral ~elevant Neutral Spot Item

Figure 7 . Mean ampli tude i n s k i n conductance response (SCR) dur ing t h e d e t e c t i o n per iod f o r each ca tegory i n t h e experimental and c o n t r o l groups.

sub jec ted to a 2 x 2 x 2 (Group x Quest ion Type x Category)

mixed-design ANOVA w i t h repeated measures on t w o i t e m

c a t e g o r i e s ( s p o t and i t e m ) wi th a nes ted f a c t o r of ques t ion

t ype , t h a t is, r e l e v a n t ve rsus n e u t r a l ques t ions .

Only Ques t ion Type produced a s i g n i f i c a n t e f f e c t , E (1,

6 2 ) = 144.20, p < .0001, i n d i c a t i n g t h a t t h e r e l e v a n t

ques t ions elicited r e l i a b l y l a r g e r SCRs than t h e n e u t r a l

ques t ions , Ms = .85 and .66 for t h e r e l e v a n t and n e u t r a l

ques t ions , r e s p e c t i v e l y (see Figure 7 ) . However, t h e alarm

t r ea tment f o r t h e i t e m ca tegory of t h e experimental group d id

not a f f e c t t h e GKT effect s i n c e n e i t h e r Category e f f e c t nor

Group x Category i n t e r a c t i o n w a s observed.

A r e l a t i o n s h i p between t h e GKT e f f e c t and t h e

p a r t i c i p a n t s ' mmory co r r ec tnes s on t h e i r selected i t e m was

examined f o r each s p o t and i t e m ca tegory separa te ly . Since

n e i t h e r group d i f f e r ence nor group x category i n t e r a c t i o n w a s

observed on t h e SCRs dur ing t h e de t ec t i on phase, both t h e

experimental and c o n t r o l p a r t i c i p a n t s were combined and

c l a s s i f i e d i n t o t w o groups depending on t h e i r memory being

c o r r e c t or i nco r r ec t f o r each s p o t and i t e m category (see

Table 2 in previous s e c t i o n ) . A 2 x 2 (Question Type x

Memory Correctness) mixed-design ANOVA with repeated measures

on ques t ion type was conducted f o r each spo t and i t e m

category. For t h e spot category, t h e only s i g n i f i c a n t e f f e c t

w a s t h e Quest ion Type, E (1, 52) = 38.94, p < .0001,

i n d i c a t i n g t h a t t h e r e l e v a n t ques t ions e l i c i t e d l a r g e r

e lec t rodermal responses t h a n t h e n e u t r a l quest ions, lB = -89

and .68 f o r t h e r e l evan t and n e u t r a l quest ions, respect ively .

For t h e i t e m category, t h e e f f e c t of t h e Question Type w a s

s i g n i f i c a n t , E (1, 5 2 ) = 39.42, p c ,0001, again ind ica t ing

t h a t t h e re levan t ques t ions e l i c i t e d l a r g e r electrodermal

responses than t h e n e u t r a l ques t ions , Ms = .85 and .69 for

t h e r e l e v a n t and n e u t r a l ques t ions , respect ively . Moreover,

t h e e f f e c t of Memory Correctness w a s also marginally

s i g n i f i c a n t f o r t h e i t e m ca tegory , E (1, 52) = 4.00, p =

.051, i n d i c a t i n g t h a t p a r t i c i p a n t s who re ta ined correct

Correct l ncorrect Memory Correctness for Selected Spot

Relevant Question

Neutral Question

Correct l ncorrect Memory Correctness for Selected Item

Figure 8. Mean amplitude of sk in conductance response (SCR) to relevant and neutral quest ions a s a function of participants' memory correctness for t h e i r own critical items. The upper panel shows t h e mean SCR i n the spot interrogation and t h e lower panel shows t h e mean SCR i n the i t e m interrogat ion .

memory of t h e i r s t e a l i n g i t e m had produced l a r g e r SCRs both

t o t h e r e l e v a n t and n e u t r a l ques t ions during t h e experiment,

Ms = .81 and -61 f o r t h e correct and incorrect memory

holders , r e s p e c t i v e l y . However, two-way Memory Correctness x

Quest ion Type i n t e r a c t i o n w a s no t s i g n i f i c a n t . These data

are displayed i n F igure 8, wi th t h e upper panel showing t h e

mean SCRs t o t h e r e l e v a n t and t h e n e u t r a l ques t ions i n t h e

spot i n t e r r o g a t i o n , and t h e lower panel showing t h e mean SCRs

i n t h e i t e m i n t e r r o g a t i o n .

F ina l ly , a r e l a t i o n s h i p between t h e GRT e f f e c t on SCRs

and types of f e e l i n g t h a t t h e experimental group p a r t i c i p a n t s

experienced when the a larm went o f f dur ing t h e pre-

experimental s c e n a r i o reading was examined. A 2 x 2 x 4

(Quest ion Type x Category x Fee l ing) mixed-design ANOVA with

repeated measures on t w o i t e m c a t e g o r i e s t h a t nes ted a factor

of ques t ion t y p e was conducted on SCR data. One p a r t i c i p a n t

who chose "aroused" as h i s f e e l i n g w a s excluded from the

ana lys i s . F igure 9 shows mean SCR amplitude t o t h e r e l e v a n t

and neu t r a l q u e s t i o n s for each f e e l i n g category.

A main e f f e c t of Quest ion Type was s i g n i f i c a n t , E (1,

21) = 74.91, p < ,0001, i n d i c a t i n g t h a t t h e r e l e v a n t

ques t ions elicited r e l i a b l y l a r g e r SCRs than t h e n e u t r a l

quest ions, = -84 and .67 for t h e r e l evan t and n e u t r a l

ques t ions , r e s p e c t i v e l y . Moreover, a tm-way Feel ing x

Quest ion Type i n t e r a c t i o n w a s also s i g n i f i c a n t , E (3 , 21) =

4.31, p < - 0 2 . Thus, a series of p a i r e d k-tests t o compare

t h e mean SCRS t o the r e l e v a n t and t h e n e u t r a l ques t ions was

Relevant Question

Neutral ' Question

~larhed Aroused Startled Interested Nothing (bl=4) a=1) @.=14) (M=3) a= 4)

Categories of Feeling for Alarm Treatment

Figure 9. Mean ampli tude of sk in conductance response (SCR) t o r e l evan t and n e u t r a l quest ions as a func t ion of feeling that participants i n t h e experimental group described how they f e l t when the alann sound went off dur ing t h e scenar io reading.

conducted i n each Feeling group separa te ly . Resul ts showed

that t h e r e l e v a n t ques t i ons produced s i g n i f i c a n t l y larger

responses than t h e n e u t r a l quest ions i n t h e " s t a r t l e d w group,

L (13) = 7.27, p < .0001, Ms = -96 ( r e l e v a n t ) and .77

( n e u t r a l ) ; the " i n t e r e s t e d " group, L ( 2 ) = 11.08, p c -01,

ZB = .81 ( r e l e v a n t ) and -53 ( n e u t r a l ) ; and t h e "nothing"

group, L (3 ) = 3.70, .04 , MS = - 6 9 ( r e l e v a n t ) and .54

( n e u t r a l ) . However, the "alarmedm group showed only

marginal ly s i g n i f i c a n t d i f f e r ence , L (3 ) = 2.72, p c .08, Ks

= - 7 4 and .69 f o r t h e r e l e v a n t and n e u t r a l ques t ions ,

r e spec t ive ly .

T i g ta the Owti~~eg+ians

During t h e d e t e c t i o n period, each p a r t i c i p a n t

accumulated 4 r e a c t i o n times t o r e l e v a n t ques t ions and 1 2

r e a c t i o n times t o n e u t r a l ques t ions f o r each s p o t and i t e m

category. These responses were averaged t o provide one m a n

r e a c t i o n t i m e s c o r e f o r r e l evan t ques t ions and one mean

r e a c t i o n t ime score f o r n e u t r a l ques t ions for each spo t and

item category. These data were sub jec ted t o a 2 x 2 x 2

(Group x Ques t ion Type x Category) mixed-design ANOVA with

repeated measures on t w o c a t ego r i e s ( s p o t and i t e m ) with a

nes ted f a c t o r of q u e s t i o n type , t h a t is, r e l e v a n t versus

n e u t r a l ques t ions .

The a n a l y s i s r evea led a s i g n i f i c a n t effect of Quest ion

Type, E (1, 6 2 ) = 8.37, p < -01, i n d i c a t i n g t h a t t h e r e ac t i on

time t o t h e r e l e v a n t ques t i on w a s s h o r t e r than t h a t t o t h e

n e u t r a l ques t ion , &s = 502.74 and 539.64 s for t h e r e l evan t

and n e u t r a l ques t ions , r e spec t i ve ly (see Figure 10).

Although an i n spec t i on of Figure 10 sugges t s t h a t t h e

r e a c t i o n t i m e measures of t h e p a r t i c i p a n t s i n t h e c o n t r o l

group were c o n s i s t e n t l y s h o r t e r than t h a t of t h e experimental

group, n e i t h e r Group e f f e c t nor any o t h e r i n t e r a c t i o n s

between factors were s i g n i f i c a n t ,

Experimental Group

Control Group

Figure 10. Mean r e a c t i o n t i m e t o t h e r e l e v a n t and neu t r a l ques t ions i n t h e experimenal and c o n t r o l groups f o r t h e spo t and t h e i t e m i n t e r roga t i on ca t ego r i e s .

The r e l a t i o n s h i p between t h e GKT e f f e c t on r eac t i on time

measures and t h e p a r t i c i p a n t s ' memory c o r r e c t n e s s of t h e i r

selected i t e m was examined i n t h e same w a y on SCR data w i t h a

2 x 2 (Quest ion Type x Memory Correc tness) mixed-design ANOVA

with repeated measures on quest ion type. Nei ther main e f f e c t

nor two-way i n t e r a c t i o n was s i g n i f i c a n t for t h e spo t

category. For the i t e m category, the o n l y s i g n i f i c a n t e f f e c t

w a s a main e f f e c t of Quest ion Type, E (1, 52) = 11.29, p <

.01, i nd i ca t i ng t h a t t h e reac t ion tirru! w a s s h o r t e r t o t h e

re levan t ques t ions than t o t h e n e u t r a l ques t i ons , Ks = 493.04

s and 541.63 s for t h e re levan t and n e u t r a l ques t ions ,

respect ive ly . N o o t h e r s i g n i f i c a n t e f f e c t was found.

Correct Incorrect Memory Correctness for Selected Spot

1200

Relevant Question

Neutral Question

Correct l ncorrect Memory Correctness for Selected Item

Figure 11. Mean react ion time to the relevant and the neutral questions as a function of part ic ipants ' memory correctness for t h e i r own critical items. The upper panel shows the wan react ion t i n e i n the spot interrogation and the lower panel shows the mean react ion time i n the i t e m interrogation.

These data are d isp layed in Figure 11, with t h e upper panel

showing t h e mean r e a c t i o n time t o r e l evan t and t h e n e u t r a l

quest ions i n t h e s p o t i n t e r roga t ion , and the lower panel

showing t h e mean r e a c t i o n t i n e i n the i t e m in te r roga t ion .

Final ly , a r e l a t i o n s h i p between t h e GKT effect on

r eac t ion t i m e m a s u t e s and types of f e e l i n g t h a t t h e

experimental group p a r t i c i p a n t s experienced when t h e alarm

went off dur ing t h e s c e n a r i o reading was examined- A 2 x 2 x

4 (Quest ion Type x Category x Feeling) mixed-design ANOVA

with repeated measures on t w o i t e m ca tegor ies wi th a nested

f a c t o r of Quest ion Type w a s conducted on t h e r e a c t i o n t i m e

da t a . The p a r t i c i p a n t who chose "aroused" a s h i s feeling was

again excluded from t h e d a t a ana lys i s . Figure 12 shows mean

r eac t ion t i m e to t h e r e l e v a n t and t h e neu t r a l ques t ions f o r

each feeling category-

A main effect of Quest ion Type was s i g n i f i c a n t , E (1,

21) = 13.62, p < ,002, i n d i c a t i n g t h a t t h e r e l evan t quest ions

e l i c i t e d r e l i a b l y s h o r t e r r eac t ion t h than t h e n e u t r a l

ques t ions , = 539.77 and 592.07 s f o r t h e r e l e v a n t and

neutral quest ions , r e spec t ive ly . Moreover, a two-way Feeling

x Quest ion Type i n t e r a c t i o n w a s a l s o s i g n i f i c a n t , E (3 , 2 1 ) =

4.71, p < - 0 2 . Thus, a series of pa i red t-tests were

conducted t o compare t h e mean reac t ion time to t h e re levan t

and t h e n e u t r a l ques t ions i n each Feeling group separa te ly .

Only t h e "nothingn group showed s i g n i f i c a n t d i f f e r e n c e i n

r eac t ion t ime between t h e r e l evan t and the n e u t r a l ques t ions ,

Relevant Question

Neutral Question

~ larhed q roused startled interested Nothing ( M = 4 ) (bl=1) (bl=14) @=3) Ibl= 4)

Categories of Feeling for Alarm Treatment

Figure 12. Mean r e a c t i o n t i m e t o t h e r e l e v a n t and t h e n e u t r a l ques t ions as a f u n c t i o n o f f e e l i n g t h a t p a r t i c i p a n t s i n t he experimental group desc r ibed as t h e y felt when t h e alarm sound had gone off dur ing t h e s c e n a r i o reading.

L ( 3 ) = 4.33, p < .03, Ms = 384.90 and 492.72 s for t h e

r e l e v a n t and n e u t r a l ques t ions , r e s p e c t i v e l y .

F m

The f o u r nove l ty e f f e c t s d u r i n g t h e PNP were defined as

fo l lows and c a l c u l a t e d for each p a r t i c i p a n t : T r i a l 1 minus

Trial 9 for h a b i t u a t i o n , T r i a l 11 minus T r i a l 9 for

d i s h a b i t u a t i o n , T r i a l 10 minus T r i a l 9 f o r OR r e ins t a t emen t

o r ORR, and T r i a l 10 minus T r i a l 1 for super ORR. As stated

above, t h e s e f o u r n o v e l t y e f f e c t s emerged r e l i a b l y i n t h e

Table 2

I n t e r c o r r e l a t i o n s between n o v e l t y and t h e GKT effects (n = 6 4 )

E f f e c t s 1 2 3 4 5 6 1. GKT (SCR) -- --28* -11 .04 .29* 022 2 . GKT (RT) Ow - e l 1 04 002 16 3. Hab i tua t ion 99 .45** .67** -.40** 4 . D i s h a b i t u a t i o n Dm .52** .08 5 . ORR -I .42** 6, Super ORR --

** p <.01, p <.05 by F i s h e r ' s r t o z

sense t h a t t h e f i rs t t e r m i n t h e f o u r equa t ions s i g n i f i c a n t l y

exceeded t h e second term. The GKT e f f e c t for each

p a r t i c i p a n t was obtained by s u b t r a c t i n g m a n responding t o

n e u t r a l q u e s t i o n s from mean responding t o r e l e v a n t q u e s t i o n s

on SCR scores and r e a c t i o n t i m e measure. The Peason ' s

product-moment c o r r e l a t i o n c o e f f i c i e n t s (rs) were c a l c u l a t e d

among t h e s e e f f e c t s wi thou t s p l i t t i n g t h e exper imenta l and

c o n t r o l groups s i n c e t h e r e were no group d i f f e r e n c e s e i t h e r

i n t h e PNP o r t h e GKT effects. The r e s u l t s are summarized i n

Table 2 .

A l l n o v e l t y e f f e c t s were s i g n i f i c a n t l y correlated t o one

ano the r e x c e p t t h e r e l a t i o n s h i p between d i s h a b i t u a t i o n and

super ORR. Moreover, one of t h e novel ty e f f e c t s , OR

r e i n s t a t e m e n t , showed a small b u t s i g n i f i c a n t p o s i t i v e

c o r r e l a t i o n w i t h t h e GKT effect i n SCR measure (r = a . 2 9 , p <

. 0 5 ) . The GKT effect i n SCR also c o r r e l a t e d s i g n i f i c a n t l y

wi th t h e GKT e f f e c t i n t h e r e a c t i o n t i m e measure (r = .28,

The f i e l d s c o r i n g method of Lykken (1959) was a p p l i e d t o

t h e d a t a t o classify t h e p a r t i c i p a n t s as e i t h e r g u i l t y o r

innocent. I n t h e exper imenta l group, 25 o u t o f 32 (78.1%)

p a r t i c i p a n t s were c l a s s i f i e d as g u i l t y . I n t h e c o n t r o l

group, 22 o u t of 32 (68.8%) were c l a s s i f i e d as gu i l t y . A X2

test w a s performed t o test f o r s i g n i f i c a n c e of t h e d i f f e r e n t

propor t ion of p a r t i c i p a n t s c l a s s i f i e d as g u i l t y i n two groups

bu t no s i g n i f i c a n t d i f f e r e n c e was revealed , X 2 ( 1, K = 64 ) =

m72, > 0 1 .

Although t h e p r e s e n t experiment was t o t a l l y d i f f e r e n t

f r o m Experiment I w i t h regard to t h e mode of ques t ion

p r e sen t a t i on as w e l l as o t h e r f ea tu r e s , a comparison was maae

between t w o experiments on t h e number of p a r t i c i p a n t s who

w e r e classified as g u i l t y . To do t h i s , t h e numbers of

p a r t i c i p a n t s i n t h e t w o immediate-answer groups i n t h e

Experiment I were combined and t h i s r e s u l t e d i n 16 o u t of 24

p a r t i c i p a n t s (66.7%) being classified as g u i l t y . S imi l a r l y ,

the numbers of p a r t i c i p a n t s i n both experimental and c o n t r o l

groups i n t h e p r e s e n t experiment were combined and t h i s

r e s u l t e d i n 47 o u t of 64 p a r t i c i p a n t s (73.4%) being

c l a s s i f i e d as g u i l t y . A X 2 t e s t revealed t h a t t h e r e was no

s i g n i f i c a n t d i f f e r e n c e on proport ion of g u i l t y - c l a s s i f i e d

p a r t i c i p a n t s between t h e two experiments, X2 (I, N = 88) =

m 3 9 , p > 0 1 .

Discussion

Three major conclusions can be drawn from the p resen t

experiment. The f i r s t is t h a t a s i g n i f i c a n t GKT e f f e c t on

SCRs, t h a t is, SCRs t o t h e r e l e v a n t ques t ions being l a r g e r

t han t h a t t o t h e neu t r a l ques t ions , was again obtained as i n

t h e Experiment I and a s i n t h e most of t h e GKT l i t e r a t u r e ,

However, t h e manipulation of s i g n a l va lue of t h e s t imulus had

no main or i n t e r a c t i v e e f f e c t s on d i f f e r e n t i a l r espons iv i ty

to t h e r e l e v a n t quest ions. Second, a weak but s i g n i f i c a n t

r e l a t i o n s h i p was observed between one of t h e four o r i e n t i n g

response indices and t h e GKT e f f e c t s i n SCRs, T h i r d ,

r e a c t i o n t i m e w a s s i g n i f i c a n t l y accelerated only t o t h e

r e l e v a n t ques t ions . Addit ional ly, t h e computer-based oral

p r e s e n t a t i o n of quest ions seems t o have functioned adequately

i n a s ense t h a t it produced t h e s i g n i f i c a n t GKT e f f e c t s .

I n r e l a t i o n t o t h e f i r s t f i n d i n g about t h e s i g n a l va lue

manipulat ion, one common account of t h e GKT e f f e c t i s t h a t

s i g n a l va lue of t h e relevant i t e m exceeds t h a t of t h e n e u t r a l

items (see, e.g., Lykken, 1974), t h u s br inging l a r g e r

r e s p o n s i v i t y t o t h e re levan t items, A more recent

formulat ion of t h i s account is t h e noteworthiness hypothesis

(Elaad & Ben-Shakhar, 1989), according t o which t h e <;KT

e f f e c t r e f l e c t s t h e degree t o which t h e re levan t Ltem are

more a t t ended t o than t h e n e u t r a l items--thus, t h e former is

more "noteworthy," The aim of t h e a larm manipulation i n t h e

p r e s e n t e x p e r i m n t w a s t o i nc rea se t h e degree t o which t h e

exper imenta l condi t ion , which c o n s i s t e d of role-playing a

crime scenar io , w a s more realistic. It was hoped t h a t t h i s

manipulation would add some s igna l value t o t h e re levant

quest ions and hence would produce a b e t t e r GKT e f f ec t . It

should be noted t h a t t h i s d i r e c t manipulation of t h e s i g n a l

value i t s e l f of t h e r e l evan t i t e m d i f f e r e d from t h e more

customary nmtivat ional manipulation by monetary incent ives

( e -g . , E l a a d 6 Ben-Shakhar, 1989; Davidson, 1968; Furedy 61

Ben-Shakhar, 1991) or by d i f f e r e n t i n s t r u c t i o n s (e.g.,

Gustafson & Orne, 1963, 1965a; E i o ~ a t h , 1979; Lieblich,

Na f t a l i , Shmueli, 6 Kugelnuss, 1974).

The alarm w a s an e f f e c t i v e st imulus, a s it produced

larger SCRs in t h e pa r t i c ipan t s of t h e experimental group

when they selected t h e i r own to-be-stolen items (see Figure

6 ) . Such enhanced SCRs might be due t o t h e pa r t i c ipan t s '

emotional r eac t ions t o t h e alarm, an idea which was supported

by t h e post-experimental i n t e r v i e w s . To t h i s extent ,

t he re fo re , it seems t h a t t h e s igna l va lue of t h e scenario as

a whole w a s enhanced. However, t h e alarm-associated re levan t

quest ions d i d no t produce grea te r SCRs than t h e o ther

quest ions , hence no s i g n a l value w a s added t o t h e quest ions

themselves. This means t h a t the experimental manipulation

w a s not success fu l t o determining whether adding s igna l value

would a f f e c t t h e de t ec t ion of information, because t h e

manipulation check by r e c a l l i n g s t o l e n i t e m s indicated t h a t

no signal va lue w a s added t o t h e quest ions themselves. I t

does appear, t he re fo re , t h a t increasing s i g n a l value of t h e

relevant i t e m is a d i f f i c u l t task i n t h e laboratory context.

Accordingly, even though t h e noteworthiness hypothesis (Elaad

& Ben-Shakhar, 1989) is c o n s i s t e n t wi th t h e GKT outcomes,

t h i s t h e o r e t i c a l cons idera t ion provides l i t t l e help i n

developing procedures t h a t maximize t h e accuracy of GKT

de tec t i on , a t least i n t h e l abo ra to ry con tex t .

An OR-reinstat-nt (OR.) obtained in t h e PNP i n d i c a t e d

a small but s i g n i f i c a n t p o s i t i v e c o r r e l a t i o n with t h e GKT

e f f e c t ( r = -29 , p < . 0 5 ) . The ORR is a component of

o r i e n t a t i o n which, after hab i tua t ion , fo l lows changes i n

s t imulus i n t e n s i t y , modality, dura t ion , frequency, sequence

(i.e., d u r a t i o n and v a r i a b i l i t y of t h e in te r s t imulus

i n t e r v a l s ) , complexity, information con ten t , or st imulus

s i g n i f i c a n c e (Boucsein, 1992) . Moreover, Furedy and Ginsberg

( 1 9 7 5 ) r epo r t ed t h a t electrodermal responses t o a modally-

changed s t imu lus tended t o be larger than those elicited a t

t h e beginning of t h e habi tuat ion series. It should be noted

that t h e con t ex tua l condi t ion i n which an ORR appears is

similar t o t h e condi t ion in which an enhanced respons iv i ty t o

t h e r e l e v a n t i t e m emerges i n t h e GKT, a t least in terms of

st imulus s i g n i f i c a n c e . I n o t h e r words, t h e r e p e t i t i v e

s t imulus and t h e modally-changed s t imulus i n t h e PNP

correspond t o t h e neu t r a l i t e m and t h e r e l evan t i t e m i n t h e

GKT r e spec t ive ly . Thus, an enhanced respons iv i ty to r e l e v a n t

i t e m s ob ta ined i n the GKT paradigm might be due t o an ORR

component o f o r i e n t a t i o n , and t h i s is what OR-based account

of the GKT such as Lykken's (1974) s i g n a l va lue hypothesis

and Ben-Shakhar ' s ( 197 7 ) dichotomizat ion hypothesis p r e d i c t s .

The s i g n i f i c a n t c o r r e l a t i o n between t h e O R . and t h e GKT

e f f e c t in t h e p r e s e n t s tudy is t h e first c o r r e l a t i v e evidence

f o r t h e i r p r ed i c t i ons .

However, t h e r value, although s t a t i s t i c a l l y

s i g n i f i c a n t , seems t o be too small in a usua l sense f o r

making a con f iden t c a u s a l inference , as it accounts for less

than 10% of t h e var iance . Because psychophysiological

measures such as SCRs are s o r e a c t i v e t o a l l s t imu l i ,

v a r i a b i l i t y of t h e response is large even i n t h e same

ind iv idua l bu t a t d i f f e r e n t po in t s of time. Thus, it is

usua l ly d i f f i c u l t to obtain a high c o r r e l a t i o n between

measures in psyc hophys i o l o g i c a l s t u d i e s . Another and more

important reason for t h e low r between t h e ORR and GKT e f f e c t

may be due to a d i f f e r e n c e in number of s t i m u l i presented

p r i o r t o t h e s t imulus change. Although it is d i f f i c u l t t o

spec i fy t h e number of t r ia ls requ i red t o ob ta in a complete

hab i tua t ion of t h e OR because hab i tua t i on depends on t h e

na ture of t h e s t imulus , it is assumed t h a t such hab i tua t ion

never occurred i n a sequence of GKT ques t ions i n t h e p resen t

s tudy, where on ly f i v e items were presented i n a random

order . To o b t a i n t h e GKT e f f e c t i n a con tex t of t h e ORR, one

should provide t h e same number of n e u t r a l i t e m s p r i o r to a

r e l evan t i t e m as the number of repeated s t i m u l i preceded a

st imulus change i n t h e PNP. If the GKT e f f e c t t r u l y

represen t s t h e ORFt, a higher c o r r e l a t i o n may be expected

between t h e OR p a t t e r n and t h e GKT e f f e c t .

The r e a c t i o n t i n e r e s u l t s sugges t t h a t t h e p a r t i c i p a n t ' s

a t t e n t i o n a l l e v e l was increased s p e c i f i c a l l y t o t h e re levan t

ques t ions and t h a t such a t t e n t i o n a l mechanism did play, a t

least, a p a r t i a l r o l e i n t h e G K T ' s e f f i c a c y t o de t ec t g u i l t

i n t h e p r e sen t experiment. Many psychological s t ud i e s have

been carried o u t w i th r eac t i on time measure (see Welford,

1980, f o r an ex t ens ive review of r e a c t i o n time s t u d i e s ) , bu t

it is d i f f i c u l t t o s p e c i f y t h e exac t psychological cons t ruc t

that t h e measure provides. Nettelbeck (1980), after

reviewing psychopathological s t ud i e s which used reac t ion t i m e

as a measure, claimed t h a t a l l t h e c o n s t r u c t s provided t o

account f o r t h e r e s u l t s of t h e s t u d i e s , such as o r i en t a t i on

and s e l e c t i o n , concentra t ion , search, a c t i v a t i o n , and

preparedness, were r e l e v a n t t o t h e concept of a t t en t ion . I n

genera l , t h e more t h e s t imulus is a t t ended to, t h e more t h e

r e a c t i o n t i m e to t h e s t imulus i s accelerated, I n l i n e with

t h i s , t h e a c c e l e r a t i o n of t h e r eac t i on t i m e which occurred

on ly t o t h e r e l e v a n t ques t ions i n t h e p r e sen t experiment can

be interpreted as i n d i c a t i n g t h a t t h e p a r t i c i p a n t s at tended

more to t h e r e l e v a n t than t h e n e u t r a l ques t ions . T h i s

i n t e r p r e t a t i o n conforms t o t h e OR-based hypothesis of t h e GKT

e f f e c t , because o r i e n t i n g is considered by many researchers

to r e f l e c t a t t e n t i o n a l process i n organisms, and, i n

p a r t i c u l a r t h o s e processes t h a t unde r l i e pass ive a t t e n t i o n t o

i n p u t (Siddle , 1991). I n o t h e r words, both t h e acce le ra t ion

of r eac t i on t k t o t h e r e l evan t items and t h e s i g n i f i c a n t

c o r r e l a t i o n between t h e GKT effect and t h e p regen t ORR

mentioned can be expla ined in terms of focused a t t e n t i o n .

S e v e r a l s t u d e n t s of t h e GKT have directly referred t o

a t t e n t i o n as a p o s s i b l e mechanism which c o n t r i b u t e s t h e GKT

effect (e.g., Day & Rourke, 1974; Elaad & Ben-Shakhar, 1989,

1990; W a i d , Orne, Cook, & O r n e , 1978; W a i d , O r n e , & Orne,

1981) , b u t none have d i r e c t l y examined measures which might

reflect t h e p a r t i c i p a n t s ' a t t e n t i o n a l l e v e l . It should be

po in ted out, however, t h a t t h e r e a c t i o n t i m e measure i n t h e

p r e s e n t s tudy was r a t h e r i n d i r e c t , as it c o n s i s t e d of asking

t h e p a r t i c i p a n t s t o h i t a computer key s imul taneous ly with

g i v i n g t h e i r o r a l answers t o t h e quest ions. A more direct

measure of r e a c t i o n t i m e i n t h e GKT c o n t e x t is vo ice la tency.

So f a r , on ly Cutrow et al . (1972) have used t h i s measure i n a

GKT-like s tudy i n which t h e y repor ted s i g n i f i c a n t l y s h o r t e r

voice l a t e n c y t o r e l e v a n t t h a n n e u t r a l ques t ions ; however

t h e y did n o t d i s c u s s the i m p l i c a t i o n of t h i s f i n d i n g , as

t h e i r primary purpose w a s t o compare use fu lness of s e v e r a l

psychophysiological i n d i c e s . Both r e a c t i o n t i m e and voice

l a t e n c y have drawbacks as indices of d e t e c t i o n of deception,

because t h e y are under v o l u n t a r y c o n t r o l of t h e human

s u b j e c t s . However, they cou ld c e r t a i n l y p rov ide a d d i t i o n a l

informat ion i n exp lo r ing t h e mechanism of d e t e c t i o n of

decept ion , e s p e c i a l l y i n a laboratory s e t t i n g .

I n t h e p resen t experinrent, t h e ques t ions were presented

i n a u d i t o r y mode by a computer synthes ized vo ice , i n c o n t r a s t

to t h e v i s u a l mode i n Experinrent I. Visual p r e s e n t a t i o n is

more convenient i n t h e sense t h a t it enab les p i c t u r e

p r e sen t a t i on and e a s y arrangement, bu t it may produce e x t r a

v a r i a b i l i t y and even artifacts as a func t ion of p a r t i c i p a n t s

not a t t end ing maximally throughout t h e pe r iod of

p resen ta t ion . Auditory p r e sen t a t i on is t e c h n i c a l l y more

complicated t o arrange, b u t may be experienced as more

similar than t h e v i s u a l p r e sen t a t i on t o a " n a t u r a l w GKT

procedure. To e x p l o r e t h i s specu la t ion , correct de t ec t i on

rates were compared between v i s u a l (66.73, when t h e two

imxxediate-answer groups in Experiment I were combined) and

aud i to ry (73.43, when both experimental and c o n t r o l groups i n

Experiment I1 were combined) p resen ta t ion , b u t no s i g n i f i c a n t

d i f f e r e n c e emerged. However, Experiment I and I1 d i f f e r e d

not only i n t h e mode of p re sen t a t i on of t h e ques t ions , but

a l s o i n s e v e r a l o t h e r a t t r i b u t e s , hence no d e f i n i t i v e

conclusion can be drawn from t h e above f i nd ings . Another

i s s u e concerning t h e accuracy of de t ec t i on and t h e computer

p r e sen t a t i on of ques t i ons i s t h e f a c t t h a t t h e d e t e c t i o n

rates were lower in comparison with t h e mean accuracy rates

of 84%, which Ben-Shakhar and Furedy (1990) provided i n their

review of 1 0 GKT s t u d i e s conducted by human examiners.

Because of p rocedura l d i f f e r e n c e s among t h e s e s t u d i e s , it i s

a l s o sorlbewhat i n a p p r o p r i a t e t o d i r e c t l y compare t h e s e data .

Yet t h e r e w a s a s i g n i f i c a n t d i f f e r ence when a comparison w a s

made between t h e accuracy rates obtained in t h e p re sen t two

experiments and t h e 10 GKT s t u d i e s i n t h e Ben-Shakhar and

Furedy's review, X2 ( I , K = 312) = 6.28, < .02, which

i n d i c a t e s t h a t t h e accuracy rate i n the present experiments

is lower than in t h e previous t e n s tud i e s . However, all t h i s

is mere specu la t ion and only more sys temat ic comparisons can

i n d i c a t e t h e e f f e c t of human versus computer p resen ta t ion of

ques t ions . Such an attempt might provide impl ica t ions f o r

understanding t h e under ly ing mechanism of t h e GKT effect.

Once a f a c t o r or f a c t o r s which produce d i f f e r e n t accuracy

rates are i d e n t i f i e d , t h e computer-based oral i n t e r roga t ion ,

which does away with t h e need f o r t h e examiner-examinee

i n t e r a c t i o n , might be f e a s i b l e to enhance t h e o b j e c t i v i t y t o

t h e GKT procedure.

GENERAL SUMMARY AND DISCUSSION

I n t h i s s tudy, t w o experiments were carried ou t t o

examine t h e accuracy of t h e GKT with SCR as a dependent

v a r i a b l e in a labora tory s i t u a t i o n where p a r t i c i p a n t s ro le-

played a crime scenar io . I n both experiments, a computer was

used t o d e l i v e r t h e GKT quest ions r a t h e r t han presenting them

o r a l l y by a human examiner. The quest ions were delivered i n

a v i s u a l mode in Experiment I and i n an aud i to ry mode i n

Experiment 11. ~ x p e r i m n t I primari ly focused on a

comparison of d e t e c t i o n e f f ic iency between immediate- and

delayed-answer condi t ions . I n Experiment If, an underlying

mechanism of t h e GKT e f f e c t was explored i n terms of t h e

s i g n a l value hypothesis (Lykken, 1974) by t r y i n g t o

manipulate t h e emotional impact of t h e quest ions .

Some of t h e major f indings and conclusions of t h e study

are as follows. F i r s t , a r e l i a b l e GKT e f f e c t was obtained i n

both experiments wi th "relevant" quest ions evoking

s i g n i f i c a n t l y l a r g e r SCRs i n t he p a r t i c i p a n t s than neutra l

ones. The e f f e c t was s i g n i f i c a n t when t h e SCRs were examined

i n t h e i n t e r v a l immediately following ques t ion onset ,

i r r e s p e c t i v e of whether t h e question had been presented i n

t h e immediate- o r t h e delayed-answer condi t ions i n Experiment

I. This i n d i c a t e s t h a t , contrary t o Nakayama et al. (1988),

t h e immediate-answer procedure would f a r e better i n field

p r a c t i c e of t h e GKT than t h e delayed-answer procedure;

furthermore t h e former is easier to deploy than t h e l a t e r .

Second, t h e manipulation of t h e s i g n a l va lue of t h e questions

i n Experiment I1 f a i l e d t o produce any d i f f e r e n t i a l

r e spons iv i ty t o t h e r e l e v a n t quest ions, Third, a weak but

s i g n i f i c a n t p o s i t i v e c o r r e l a t i o n w a s observed between t h e GKT

effect and p a r t i c i p a n t s ' o r i en t i ng response p a t t e r n s with

r e spec t to OR re ins ta tement , which is t y p i c a l l y aroused by a

sudden change of s t imu lus p a t t e r n o r mrodality, This r e s u l t

suggests an a t t e n t i o n a l or o r i en t i ng cons idera t ion of t h e GKT

e f f e c t . Fourth, r e a c t i o n time was s i g n i f i c a n t l y accelera ted

only t o t h e r e l evan t ques t ions i n both experiments, which

lends f u r t h e r suppor t t o an a t t e n t i o n a l i n t e r p r e t a t i o n of t h e

GKT e f f e c t . F i f t h , n o s ex d i f fe rence w a s observed in t h e GKT

e f f e c t i n Experiment L , Fina l ly , a l l t h e observat ions

described above were ob ta ined by t h e computer-assisted

i n t e r roga t i on i n which no human examiner-examinee i n t e r ac t i on

w a s needed--a procedure t h a t eliminated b i a s due t o human

sub jec t ive admin i s t ra t ion .

The mechanism under ly ing t h e d i f f e r e n t i a l , enhanced

psychophys i o l o g i c a l respons i v i t y t o t h e r e l e v a n t quest ions

has not been f u l l y understood i n t h e GKT, al though it is even

more obscure i n t h e case of t h e CQT. Severa l hypotheses have

been proposed t o e x p l a i n t h e way i n which autonomic responses

might be respons ib le in t h e de tec t ion of g u i l t or ly ing.

Davis (1961) suggested three explanations: t h e conditioned

response hypothesis, the punishment hypothesis , and t h e

c o n f l i c t hypothesis.

The condit ioned response hypothesis assumes t h a t

r e levan t items play t h e r o l e of condit ioned s t i m u l i and evoke

enhanced r e spons iv i t y t o t h e re levan t ques t i on w i th which

t h e y have been associated i n t h e p a s t (e.g., crime).

However, as Davis (1961) has a l ready noted, t h e s imple

condi t ioned response hypothes is could hardly be t h e whole

exp lana t ion f o r t h e enhanced responsiv i ty . For example, many

l abo ra to ry e x p e r i m n t s have demonstrated s u c c e s s f u l de tec t ion

of a card number, picked by t h e p a r t i c i p a n t before t h e

i n t e r r o g a t i o n procedure. I n such cases, it seems un l ike ly

t h a t t h e s t rong a s s o c i a t i o n between a card number and

enhanced psychophysiological response has been es tab l i shed .

Although supplemental, some of t h e p a r t i c i p a n t s i n Experiment

I1 received an alarm sound when they picked up t h e i r own

items of t h e f t and t h e a la rm caused t h e l a r g e s t SCRs

throughout t h e experiment. I n a sense, t h e procedure

resembles classical cond i t i on ing of SCR, wi th i t e m as a

condi t ioned s t imulus and t h e alarm as an unconditioned

s t imulus . However, t h i s one-shot cond i t ion ing apparen t ly

failed t o produce l a r g e r SCRs s i n c e t h e GKT effect did not

d i f f e r between items which were assoc ia ted w i th t h e alarm and

items which were not.

The punishment hypothes is suggests t h a t the emotional,

and t h u s enhanced, response t o t h e r e l evan t i t e m i s due t o

fear of t h e consequences of t h e p a r t i c i p a n t ' s f a i l u r e t o

deceive. However, t h i s hypothesis does not e x p l a i n why t h e

s p e c i f i c larger response is produced only t o t h e r e l e v a n t

ques t ions . Moreover, in t h e usual laboratory experiments,

t h e p a r t i c i p a n t is no t punished i n any way i f he or she f a i l s

t o dece ive and t h i s was a l s o t r u e i n the p re sen t study.

The c o n f l i c t hypothes is a t t r i b u t e s t h e enhanced

autonomic respons iv i ty of t h e re levant i t e m t o c o n f l i c t i n g

t endenc ies between t e l l i n g t h e t r u t h and ly ing. The more a

person tries t o pass t h e d e t e c t i o n t e s t ( i n t e n s i v e

mot iva t ion) , t h e more i n t e n s e t h e c o n f l i c t becomes. This

hypothesis has been p a r t i a l l y supported by s t u d i e s which have

shown t h a t verbal l y i n g enhances the rate of d e t e c t i o n (e.g.,

Elaad & Ben-Shakhar, 1989; Furedy & Ben-Shakhar, 1991;

Gustafson & O m e , 1965; Horneman & O'Gorman, 1985). On t h e

o t h e r hand, t he se s t u d i e s also demonstrated t h a t s i g n i f i c a n t

d e t e c t i o n of re levan t informat ion w a s possible even i n a

cond i t i on where t h e p a r t i c i p a n t s did n o t respond ve rba l ly t o

t h e ques t ion. Moreover, this hypothesis has d i f f i c u l t y i n

accounting f o r t h e r e s u l t s of a s tudy by Kugelmass, Liebl ich ,

and Bergman ( 1967 ) , which compared pa r t i c ipan t ' s "No"

response ( l y i n g ) wi th a "Yes" response (confess ing) t o t h e

r e l e v a n t i t e m . I n t h i s s tudy , no di f ferences were obtained

between t h e t w o ve rba l responses--in both of which, t h e

r e l e v a n t i t e m w a s detected a t b e t t e r than chance rates, using

changes i n skin r e s i s t a n c e . Simi lar ly , t h e r e s u l t s from t h e

r e a c t i o n t i m e measure i n t h e p re sen t study are a t var iance

wi th t h e c o n f l i c t hypothes is , as react ion time was

accelerated when t h e p a r t i c i p a n t s gave t h e i r answers t o t h e

r e l e v a n t quest ions.

I n c o n t r a s t t o t h e s e e a r l y hypotheses and s t u d i e s

stressing emotional and m o t i v a t i o n a l v a r i a b l e s as t h e major

f a c t o r s de termining d i f f e r e n t i a l response i n t h e

psychophysiological d e t e c t i o n s i t u a t i o n , later r e s e a r c h has

focused o n c o g n i t i v e factors. Lykken (1974) suggested that

p r i o r knowledge of t h e relevant items provides them wi th a

s i g n a l v a l u e or s t imulus s i g n i f i c a n c e t h a t c o n s t i t u t e s

enhanced o r i e n t i n g responses ( O m ) t o t h e items.

Electrodermal ORs have been e x t e n s i v e l y researched and, as a

g e n e r a l l y accepted r e s u l t , t h e OR fol lowing a c e r t a i n

s t imulus or a class of s t i m u l i can be enlarged i f t h o s e

s t i m u l i are given s i g n a l v a l u e for a c o g n i t i v e or a motor

r e a c t i o n (Boucsein, 1992). Therefore, according t o Lykken's

hypothes is , n e i t h e r decep t ion (hence, c o n f l i c t or f e a r ) nor

heightened motivat ion t o avoid d e t e c t i o n i s necessary f o r

d e t e c t i n g t h e information; the a c q u i s i t i o n of t h e r e l e v a n t

informat ion is s u f f i c i e n t t o detect such information.

Indeed, Kugelmass e t al. (1967) demonstrated t h a t d e t e c t i o n

w a s n o t affected by t h e act of l y i n g , and s e v e r a l s t u d i e s

have demonstrated psychophysiological d e t e c t i o n i n a state of

l o w mot iva t ion (e.g., Davidson, 1968; Kugehnass & Lieb l i ch ,

1966; L i e b l i c h , N a f t a l i , Shmueli, & Kugelmass, 1974).

This k ind of o r i e n t i n g account f o r t h e GKT e f f e c t w a s

p a r t i a l l y supported by t h e r e s u l t of Experiment 11, t h a t one

of OR components, OR-reinstatement (ORR), i n d i c a t e d a smal l

but s i g n i f i c a n t correlation w i t h t h e GKT e f f e c t . Hoever , i t s c o e f f i c i e n t of de te rmina t ion was less than 10% (IZ =

.084), hence factor o r f a c t o r s o t h e r than t h e OR ought to

c o n t r i b u t e t h e GKT e f f e c t . Moreover, Bradley and Warfield

(1984) showed higher d e t e c t i o n rates i n a sample of g u i l t y

p a r t i c i p a n t s than i n a sample of innocent p a r t i c i p a n t s who

were only informed of t h e d e t a i l s of t h e crime, and who

could, thus , recognize a l l t h e r e l evan t items. They argued

t h a t although g u i l t y knowledge was necessary for de tec t ion ,

it was not a s u f f i c i e n t cond i t i on f o r de tec t ion . These

r e s u l t s raise d i f f i c u l t i e s f o r t h e theoretical approaches

t h a t base psychophysiological de t ec t i on on g u i l t y knowledge

p e r se. I n o t h e r words, as Ben-Shakhar and Furedy (1990)

claimed, "no s i n g l e theory or s i n g l e t h e o r e t i c a l approach is

capable of providing a f u l l account f o r t h e da ta . Rather, an

i n t e g r a t i o n of t h e d i f f e r e n t approaches is needed i n o rder t o

achieve a b e t t e r understanding of t h e mechanisms involved i n

psychophysiological de t ec t i on" (p. 113).

The reac t ion t i m e d a t a i n t h e present s tudy i n d i c a t e

s t rong ly t h a t r eac t i on time was s i g n i f i c a n t l y accelerated

only t o t h e r e l evan t ques t ions . It is noteworthy t h a t

r e a c t i o n t i m e w a s i nves t i ga t ed in r e l a t i o n t o d e t e c t i o n of

deception as early as a t t h e t u r n of t h e twent ie th century

and app l ied i n a real life cr imina l inves t iga t ion . Among

t h e s e pioneers w a s Jung (1906/1973, 1 9 1 0 ) , who app l ied his

assoc ia t ion- reac t ion w t h o d of s tudying mental processes t o

t h e de t ec t i on of ly ing. I n t h e associa t ion-react ion method,

a series of words was presented t o a person one by one, and

t h e person w a s requested t o respond t o t h e word (stimulus-

word) as quickly as p o s s i b l e by o r a l l y answering t h e first

word which came t o mind i n response t o t h e stimulus-word.

Response l a t e n c y , n-ly, r e a c t i o n t i m e was measured for each

word. On t h e basis of unusua l ly long r e a c t i o n t imas , i n

a d d i t i o n t o t h e n a t u r e of t h e v e r b a l response, emotional

complexes were inferred. Jung'S primary i n t e r e s t in t h e

method l a y i n t h e d i a g n o s i s o f t h e emotional complexes

under ly ing h y s t e r i a and neuras then ia (Jung, 1906/1973). I n a

crime-related u s e of t h e a s s o c i a t i o n - r e a c t i o n method, a l i s t

of stimulus-words con ta ined s e v e r a l words r e l a t i n g t o t h e

crime. I f t h e r e a c t i o n t i m e t o t h e s e critical words was

found t o be long, t h e examinee was thought t o be t r y i n g t o

dece ive and t h u s be ing g u i l t y . Jung (1906/1973) provided a

case of real embezzlement i n which he investigated a suspect

which he judged as g u i l t y , and who later confessed t o t h e

crime. Severa l r e s e a r c h e r s followed h i s method i n

exper imenta l s i t u a t i o n s and found t h a t r e a c t i o n times tended

t o be longer whenever decep t ion was p r a c t i c e d (e.g. , Henke &

Eddy, 1909; Leach & Washburn, 1910; Yerkes & Berry, 1909).

Marston (1920), who is best known for h i s

psychophysiological s t u d y of decept ion and f o r in t roduc ing

t h e n o t i o n of " s p e c i f i c l i e responsew i n t o t h i s axea, s tud ied

r e a c t i o n t ime under laboratory cond i t ions , employing a task

which was d i f f e r e n t from t h e a s s o c i a t i o n - r e a c t i o n method. I n

t h e t a s k , t h e p a r t i c i p a n t s were i n s t r u c t e d t o e i t h e r obey

( h o n e s t ) or d isobey ( l y i n g ) r e q u e s t s to perform arithmetical

c a l c u l a t i o n on sets of numbers. The time r e q u i r e d t o answer

each c a l c u l a t i o n was neasured and it was p red i c t ed t h a t

r e a c t i o n t imes would be l onge r when t h e p a r t i c i p a n t s t r i e d t o

dece ive t h e experimenter. Marston (1920) found three types

of p a r t i c i p a n t s on t h e b a s i s of t h e i r r e a c t i o n times when

they were ly ing : Those whose responses were c o n s i s t e n t l y

long; t h o s e whose r e a c t i o n t imes were i n c o n s i s t e n t from day

t o day; and t hose whose r e a c t i o n times were c o n s i s t e n t l y

s h o n . However, Golds te in (1923), i n an attempt t o r e p l i c a t e

Marston 's experiment, failed t o f i n d support for t h e

e x i s t e n c e o f the t h i r d t ype o f p a r t i c i p a n t s whose r eac t i on

t i m e was shortened when t h e y p r ac t i c ed ly ing , arguing t h a t

t h e p a r t i c i p a n t s wi th s h o r t r e a c t i o n t i m e were simply not

involved i n t h e t a s k of deceiv ing t h e experimenter.

Golds te in (1923) concluded, mostly by depending on

i n t r o s p e c t i v e reports by the p a r t i c i p a n t s , t h a t t h e

consciousness of decept ion appeared as f e e l i n g o f s t r a i n ,

se l f -consciousness , h e s i t a t i o n , c o n f l i c t of impulses, and

emotional d i s tu rbances and t h i s led t o longer r e a c t i o n times

when l y i n g was p rac t i ced . The whole argument raised

cons ide rab le cont roversy (e-g., English, 1926; Golds te in ,

1923; Marston, 1925; Rich, 1926), bu t , a s a gene ra l

conclus ion , whenever cons ide rab le a f f e c t is genera ted with

decept ion , r e a c t i o n times would probably i n c r e a s e (Orne,

Thackray, & Paskewitz, 1972)-

I n c o n t r a s t to t h e above, r e a c t i o n t ime i n t h e present

s tudy was accelerated on ly t o t h e r e l evan t ques t ion , about

which, ope ra t i ona l l y , t h e p a r t i c i p a n t s were l y ing .

Therefore, it seems t h a t t h e p a r t i c i p a n t s in t h e p r e s e n t

s tudy were n o t conscious o f dece iv ing when they responded t o

the relevant ques t ions , I n o t h e r words, a cons ide rab le

a f f e c t such as c o n f l i c t and emotional d is turbances (e.g.,

Davis, 1961) i s no t necessary t o produce l a r g e r responses t o

r e l e v a n t ques t ions , at least i n t h e laboratory GKT. Rather

it appears t h a t t h e p a r t i c i p a n t s ' a t t e n t i o n t o t h e r e l e v a n t

ques t ions c o n t r i b u t e s a reliable GKT effect--as witnessed,

p a r t i a l l y , by t h e s i g n i f i c a n t negat ive c o r r e l a t i o n between

r e a c t i o n time and t h e SCR i n t h e GKT e f f e c t (r = 0.28, p <

. 0 5 ) . I n a real l i fe d e t e c t i o n of deception, r e a c t i o n t ime

t o q u e s t i o n s may no t be u s e f u l because it is under voluntary

c o n t r o l by humans, Under l a b o r a t o r y condi t ions , however, it

provides a d d i t i o n a l informat ion t o understand t h e mechanism

underlying t h e GKT effect, i f p a r t i c i p a n t s are no t aware t h a t

t h e i r r e a c t i o n t ime is being c o v e r t l y measured.

Recent ly, measures of b r a i n electrical a c t i v i t y ,

commonly r e f e r r e d t o as even t - re l a t ed b r a i n p o t e n t i a l s

(ERPs) , have been c la iming t h e a t t e n t i o n of r e s e a r c h e r s i n

t h e d e t e c t i o n f i e l d (Bashore & Rapp, 1993) . Several GKT

l a b o r a t o r y s t u d i e s have been carried o u t w i t h a P300--one

component o f ERP-as a dependent measure and t h e s e s t u d i e s

have provided promising data on d e t e c t i o n e f f i c i e n c y (e.g.,

Farwell & Donchin, 1991; Rosenfeld, Cantwell, Nasman, Wojdac,

Ivanov, & Mazzeri, 1988; Rosenfeld, Nasman, Whalen, Cantwell,

6 Mazzeri, 1987) . The P300 is t y p i c a l l y genera ted under t h e

"oddbal l paradigm, i n which a p a r t i c i p a n t is r e q u i r e d t o

monitor a series of stimulus events comprising two stimuli.

One of the stimuli, often referred to as the "standardw

stimulus, has a .8 to .9 probability of occurring during each

trial, while the other, the "targetw stimulus, occurs with

probability between .1 and .2 and is interspersed among the

standard stimuli. When the participant is simply asked to

count the occurrence of the infrequent-whence "oddw--target

stimulus, the P300 is observed as a large positive deflection

following the presentation of the target stimulus.

Therefore, the oddball paradigm in many ways resembles the

GKT paradigm, i n which, in terms of stimulus probability, the

relevant and neutral questions serving as the target (odd)

and standard stimuli, respectively.

To make the oddball paradigm more suitable for the

detection of deception, Farwell and Donchin (1991) employed

three categories of stimuli in their P300-based GKT study,

namely, probe, irrelevant, and target stimuli. The probe

stimuli were crime-relevant items in a crime scenario and had

a .17 probability of occurring during the test. The

irrelevant and target stimuli were crime-irrelevant but

indistinguishable from the probe stimuli if the participants

were innocent, and had a probability of .66 and -17,

respectively of occurring during the test. The participants

were requested to press one response button when the target

stimuli appeared and press the other when the irrelevant and

probe stimuli appeared. Note, however, that the probe

stimuli were not distinguished in the instructions given to

the par t ic ipants- - they were on ly informed of t h e target and

nonta rge t d i s t i n c t i o n . Therefore, i f a p a r t i c i p a n t e l i c i t e d

a l a r g e r P300 t o t h e probe s t i m u l i , it could be argued t h a t

t h e p a r t i c i p a n t had d i sc r imina ted between t h e probe and

i r r e l e v a n t s t i m u l i and hence he or she possessed g u i l t y

knowledge. With t h i s c l e v e r l y designed nmthod, Farwel l and

Donchin (1991) repor ted c o r r e c t c l a s s i f i c a t i o n rate of 87.5%.

One p o t e n t i a l advantage of t h e ERP index over pe r iphe ra l

responses f o r de t ec t i ng decep t ion is i ts s h o r t e r o n s e t

l a tency . As t h e name implies, t h e P300 peaks around 300 m s

after s t imulus p resen ta t ion , provided t h e p a r t i c i p a n t is

a c t i v e l y a t t end ing t o t h a t stimulus-far s h o r t e r time than

the o n s e t la tency of p e r i p h e r a l responses such as

electrodermal a c t i v i t y , which is usua l ly masured in 1 t o 5

s time-window a f t e r s t imulus presenta t ion. Therefore, t h e

P300 may r e f l e c t a pure ly c o g n i t i v e process of conceal ing

informat ion or deception, and, t hus , t h e P300 could become a

reliable index f o r exp lor ing t h e mechanism involved in the

GKTo However, from a p r a c t i c a l po in t of view, t h e r e are

enormous problems of so f tware e x p e r t i s e and c o s t s in

developing an ERP-based test and equipment which would be

usab l e i n t h e f i e l d (Ben-Shakhar 6 Furedy, 1990). Moreover,

the ERPs are vulnerable t o artifacts caused by subtle body

movements and even by eyebl inks ; t hus obta in ing reliable ERP

records seems t o be d i f f i c u l t , i f not impossible, without t h e

examinee's coopera t ive a t t i t u d e toward t h e test. I n fact,

a f t e r conducting GKT on real life cr iminal suspects by

concur ren t ly measuring t h e P300 and t h e conventional

autonomic responses, Miyake, Mizutani, and Yamamura (1993)

concluded t h a t t h e conventional pe r iphe ra l measures were

s u f f i c i e n t f o r de t ec t i on because t h e P300s were too noisy to

make correct c l a s s i f i c a t i o n in t h e f ie ld . I n t h e i r s tudy, 18

suspects were given t h e test and 12 of them were c l a s s i f i e d

as g u i l t y and 6 as innocent, on t h e basis of autonomic

measures. The accuracy rate of t h e c l a s s i f i c a t i o n w a s 100%,

as later confirmed by confessions or arrests of t h e real

cr iminals . However, only 44% of t h e suspects were c l a s s i f i e d

c o r r e c t l y on t h e b a s i s of t h e P300 index. Moreover,

recording ERPs had t o be abandoned halfway i n 5 cases because

of a r t i f a c t s caused by eye movements and eyeblinks.

Accordingly, t h e E m b a s e d GKT a t t h i s s t a g e seems s u i t a b l e

only t o laboratory exp lora t ion of t h e underlying mechanism-of

t h e GKT.

F ina l l y , t h e labora tory- to- f ie ld genera l i za t ion problem

i s e s p e c i a l l y complex in t h i s area (Furedy & Ben-Shakhar,

1 9 9 1 ) . For example, it is pos s ib l e t h a t t h e delayed-answer

cond i t ion i s supe r io r t o t h e immediate-answer cond i t ion i n

t h e f i e l d , where an examinee's motivat ion t o deceive, i f

g u i l t y , i s s u r e l y h igher than t h a t of p a r t i c i p a n t s i n

l abora to ry experiment. With heightened motivation, the

examinee may t r y t o contaminate h i s or her physio logica l

responses by phys ica l countermeasures accompanied by oral

answers--the s t r a t e g y which may d e t e r i o r a t e t h e physio logica l

responses e s p e c i a l l y i n the ilmrurdiate-answer condit ion.

Therefore, the only way to evaluate these practical efficacy

issues is in the field itself. However, efforts to study the

GKT under controlled laboratory circumstances are still

useful for the standardization of the GKT and for furthering

understanding of its underlying mechanism, because such

parametric investigations can provide information which leads

to formulation of the application-related hypotheses. The

computer-assisted GKT seems advantageous both in the

laboratory experiments and field practice, in the sense that

it will provide GKTs that are more objectively administered

than with a human examiner.

REFERENCES

Alpert, M., Kurtzberg, R. L., & Friedhoff, A. J. (1963). Transient voice changes associated with emotional stimuli. m, GeneralPsvehiatrv,, 362-365.

Barland, G. H., & Raskin, Do C. (1973). Detection of deception* In W. F o Prokasy 6 Dm C. Raskin (Eds.), - (PP- 417.477)- New York: Academic Press.

Barland, G. Ho, 61 Raskin, D. C. (1975). An evaluation of field techniques in detection of deception. a, l2, 321-330.

Bashore, T. R., h Rapp, P. E. (1993). Are there alternatives to traditional polygraph procedures? Bulletin, 113, 3-22.

Ben-Shakhar, G. (1977). A further study of the dichotomization theory in detection of information. Psy-, 14, 408-413.

Ben-Shakhar, G. (1991). Clinical judgment and decision- making in CQT-polygraphy: A comparison with other pseudoscientific applications in psychology. -ve -, Science,, 232-2408

Ben-Shakhar, G., Bar-Hillel, M., & Lieblich, I. (1986). Trial by polygraph: Scientific and juridical issues in lie detection. Behavioral Scieace and them, 4, 459- 479 0

Ben-Shakhar, G., 6 Furedy, J. J. (1990).

York: Springer-Verlag.

Ben-Shakhar, G., Lieblich, I., & Bar-Hillel, M. (1982). An evaluation of polygraphers' judgments: A review from a decision theoretic perspective. Jaurnal -ed -, 6.2, 701-7130

Ben-Shakhar, G., Lieblich, I., & Kugelmass, S. (1970). Guilty knowledge technique: Application of signal detection measures. Journal of Ps-, X, 409-413 .

Berlyne, D. (1960). Conflict,- New York: McGraw-Bill.

Blinkhorn, S. (1988). L ie d e t e c t i o n as a psychometric procedure. I n A. G a l e ( E d s , ) , f t : ties,

s c i e n c e (pp. 29-39). London: Sage.

Boucsein, W. (1992). . . . New York: Plenum Press .

Bradley, M. T!, & Warfield, J. F. (1984). Innocence, information, and t h e g u i l t y knowledge test i n t h e d e t e c t i o n o f deception. e, a, 683-689.

Cutrow, R. J., Parks, A., Lucas, N., & Thomas, K. (1972). The objective use of mu l t i p l e phys io log i ca l indices i n the detection of deception. a, 2, 578- 588.

Davey, G. C. L., & Singh, J. (1988). The Kamin 'blocking' e f f e c t and elec t rodermal cond i t i on ing in humans. Journal

Davidson, P. 0. (1968). V a l i d i t y of t h e guilty-knowledge technique: The e f f e c t s of mot iva t ion . Jaurnal p S V c h f 5.2, 62-65.

Davis, R. C . ( 196 1 ) . Physio logica l responses as a means of e v a l u a t i n g information. I n A. D. Biderman & H. Zimmer ( E d s - ) , The (PP. 142- 168). New York: John Wiley & Sons.

Dawson, M. E. (1980). Phys io logica l d e t e c t i o n of deception: Measurement of responses to ques t i ons and answers during countermeasure maneuvers. e, U, 8-17.

Day, D. A,, 61 Rourke, B. P. (1974). The role of a t t en t i on i n " l i e d e t e c t i o n " . m, 6, 270-2760

~e Paulo, B!, & P f e i f e r , R. (1986). On-the job experience and s k l l l a t de t ec t i ng decept ion.

Psvchalaqy., J&, 249-67.

Ekman, P. (1985). - l i e s t C t o t . . a. New York: W. W. Norton C Company.

Ekman, P., & Fr i e sen , W. V. (1969). Nonverbal leakage and c l u e s t o decept ion. w, 32, 88-106.

Ekman, P., & Fr i e sen , W. V. (1974). De tec t ing deception from t h e body or face . Journal of p e r s o n a l i t y and S- -, 22, 288-298.

Elaad, Eo, 6 Ben-Shakhar, G. (1989). E f f e c t s of motivation and verbal response type on psychophysiological de tec t ion of information. -, 26, 442-451.

Elaad, Em, & Ben-Shakhar, G. (1990)- E f f e c t s of m n t a l countermeasures on psychophysiological de tec t ion i n t h e g u i l t y knowledge test, Iatarnational J0uraal-L PsvchoDhys ll, 99-108-

English, H. 8. (1926). Reaction-time symptoms of deception. Je of P s ~ , 3.2, 428-4290

Farwell, La A,, 6 Donchin, Em (1991). The t r u t h w i l l out: I n t e r roga t ive polygraphy ( " l i e de t ec t ion" ) with event- related p o t e n t i a l s , a ialnav_,, 531-547.

Fowles, D m C., C h r i s t i e , M, J., Edelberg, R., Grings, W. W., Lykken, D m T., & Venables, P. H a (1981). Publicat ion recommendations for electrodermal measurements. -, l& 232-239.

Furedy, J. J. (1968). Human o r i en t ing reaction as a function of electrodermal versus plethysmographic response modes and s i n g l e versus a l t e r n a t i n g s t imulus series. Journal

Ps-, LZ, 70-78.

Furedy, Jo J. (1985). Credulous vs. cr i t ical po l ice use of t h e polygraph i n criminal inves t iga t ion . . . Journal, 22, 491-495.

Furedy, J. J. (1986) . L i e de tec t ion as psychophysiological d i f f e r e n t i a t i o n : Some f i n e lines. I n M a G. H a Coles, Em Donchin, 6 S. W. Porges ( ~ d s . ) , -: Svstems. (pp. 683-701). New York: Gui l ford Press.

Furedy, J. J. (1987) . Evaluating polygraphy from a psychophysiological perspective: A spec i f ic -e f fec t s ana lys i s . a Scf , 22, 145-152 l

Furedy, J. J. (1989). The de tec t ion of deception: Some s c i e n t i f i c , societal, and c u l t u r a l considerat ions. I n N. W, Bond 6 D, A. T. Siddle (Eds.), -: Issues and (pp. 247-259). ~or th-Hol land: Elsevier Science Publ i sher B. V.

Furedy, J. J. (1991). Alice-in-Wonderland terminological usage i n , and comrmunicational concerns about, t h a t pecu l i a r ly American f l i g h t of technological fancy: The CQT polygraph. D&epakiva P p Science, 26, 241-247-

Furedy, J o J o (1993a). The 'control' quest ion 'test' (CQT) polygrapher's dilemma: Logico-ethical considerations f o r psychophysiological p rac t i t ioners and researchers.

JoUrnal of Ps-, fi, 263.267.

Furedy, Jo J. (1993b). Electrodema1 a c t i v i t y as a tool for d i f f e r e n t i a t i n g psychological processes i n human experimental preparations: Focus on the psyche of psychophysiology. I n J-C. Roy, W. Boucsein, Do C . Fowles, h J o H o Gruze l i e r (Eds.), jn electrodermal ((pp. 61-71). New York: Plenum Press.

Furedy, J. 3. (1996). Some e lementa ry d i s t i n c t i o n s among, and comments concerning, the 'control' question ' test ' (CQT) polygrapher's many problems: A rep ly t o Honts, Kircher, and Raskin. International JQllLZlbl of &, ,, 53-59.

Furedy, Jo J., & Ben-Shakhar, G o (1991). The roles of deception, i n t en t ion t o deceive, and motivation t o avoid de tec t ion i n t h e psychophysiological detect ion of gu i l ty knowledge. -, 28, 163-171.

Furedy, J. J., & Ben-Shakhar, G o (1993). Rhetoric without reason: A rep ly t o Honts. e, X, 319-321.

Furedy, J o J., Davis, C., & Gurevich, Mm (1988). Di f fe ren t ia t ion of deception as a psychological process: A psychophysiological approach. -, X, 683-688

Furedy, Jo J., G i g l i o t t i , F., & Ben-Shakhar, G. (1994). Electrodermal d i f f e ren t i a t ion of deception: the e f f e c t of choice versus no choice of deceptive items.

Journal of P s y c h o D h v s , Uf 13-22.

Furedy, J. J o t & Heslegrave, Ro 3. (1988). Val idi ty of the l ie detector : A psychophysiological perspective.

e andRehaviar, U, 219-241.

Furedy, J o J., & Heslegrave, Ro Jo (1991). The forensic use of t h e polygraph: A psychophysiological analysis of cur ren t t rends and fu tu re prospects. I n P. Ko Ackles, JI R. Jennings, & M. Go Ho C o l e s [Edso), Advance i n

(pp. 157489) . London: Jess ica Kingsley Publisher.

Furedy, J. J., & L i s s , Jo (1986). Countering confessions induced by t h e polygraph: O f confessionals and psychological rubber hoses. 0-

. . I

22, 92-114.

Furedy, J. J., Posner, R. T., & Vincent, A. (1991). Electrodermal d i f f e r e n t i a t i o n of decept ion: perceived accuracy and perce ived memorial c o n t e n t manipulations.

J o o f f lL, 91-97.

Ginsberg, S., & Furedy, J. J. (1974). S t imulus r e p e t i t i o n , change and assessments of s e n s i t i v i t i e s o f t h e r e l a t i o n s h i p s among an electrodermal and two p l e thysmgraph i c components of t h e orienting reac t ion . -, u, 35-43.

Goldstein, E. Re (1923). Reaction t imes and t h e consciousness o f decept ion. Anrerican Jo- v, X, 562-581.

Graves, Re, & Bradley, R. (1987). Mi l l i second interval timer and aud i t o ry reaction t i m e program for t h e IBM PC.

Graves, R., & Bradley, R. (1988). More on mi l l i second t iming and t a ch i s t o scope a p p l i c a t i o n s f o r t h e IBM PC, Behavior

2.Qh 40808-412,

Grings, W. W. (1974). Recording of electrodermal phenomena. I n R. F. Thompson 4 M. M. Pa t t e r son (Eds.) ,

273-296). New York: Academic Press .

Gudjonsson, G. 8. (1982). Some psychologica l determinants of e lec t rodermal responses t o decept ion. Personality and . . Indlvldual, 2, 381-391.

Gudjonsson, G. H. (1992). The of 3-, canfessions.. New York: John W i l e y & Sons.

Gustafson, L. A , , & O r e , M. T. (1963). E f f e c t s of heightened mot iva t ion on t h e d e t e c t i o n of decept ion. Journal, Aoalied, 408-411.

Gustafson, L. A,, & O r n e , M e T. (1964). The e f f e c t s o f t a s k and method o f s t imu lus p r e sen t a t i on on t h e d e t e c t i o n of deception. J o u r n ; l l d AaDlieds-, 48, 383-387.

Gustafson, L, A,, & O r n e , M. T. (1965a). E f f e c t s of perceived role and role success on t h e d e t e c t i o n of deception. Journal of Ps-, 42, 412-417.

Gustafson, La A,, & Orne, M. T. (1965b). The e f f e c t s of ve rba l responses on the laboratory d e t e c t i o n o f deception. m, 2, 10-13,

Benke, F. G., & Eddy, M. W. (1909). Mental d i a g n o s i s by reaction method. m, U, 399-409.

Honts, C. R. (1993). H e a t wi thout l i g h t : A review o f Theories and applications in t h e detection o f deception. -, ,, 317-319.

Honts, C. R., Ki rcher , J. C., & Raskin, D. C. (1995). Polygrapher ' s dilemma or p s y c h o l o g i s t ' s chimaera: A r e p l y t o Furedy ' s log ico-e th ica l c o n s i d e r a t i o n s f o r psychophysiological p r a c t i t i o n e r s and r e sea rcher s .

Journal--, 2Q, 199-207.

Honts, C. R., & Raskin, D. C. (1988). A f i e l d s t u d y of t h e v a l i d i t y of t h e directed lie control ques t ion . ;[ournal . . of, Science, 56-61.

Horneman, C. J., & O'Gorman, J. G. (1985). D e t e c t a b i l i t y i n t h e card tes t as a func t ion of t h e s u b j e c t ' s ve rba l response. -, 22, 330-333.

Horvath, Fa (1978). An experimental comparison of t h e psychologica l stress e v a l u a t o r and t h e g a l v a n i c sk in response i n d e t e c t i o n of decept ion. Journalof 4ppLiee -, a, 338.344.

Horvath, Fa (1979). E f f e c t of d i f f e r e n t mot iva t iona l i n s t r u c t i o n s o n d e t e c t i o n of decep t ion w i t h t h e psychologica l stress e v a l u a t o r and t h e g a l v a n i c sk in response. Journal of f , 64, 323-330.

Jung, C. G. (1906/1973). The psychologica l d i a g n o s i s of evidence. In H. Read, M. Fordham, G. Adler , & W. McGuire (Edsm 1 , The-e~ted - o f 9 Fol - 7 ) : ) (pp. 318-352). P r ince ton , N. J. : Prince ton U n i v e r s i t y Press .

Jung, C. G. (1910). The association method. American J o u r . of Ps-, a, 219-269,

K i m m e l , 8. D., & H i l l , F. A. (1961). A comparison of two electrodermal measures of response t o stress.

e , 14, 395-397.

Kimmel, 8. Dm, 6 K i m m e l , E. (1965). Sex d i f f e r e n c e s i n adap ta t ion of t h e GSR under r epea ted a p p l i c a t i o n s of a v i s u a l s t imulus . ;Tournal Ps-, m, 536-537

Kircher , J. C., & Raskin, D. C. (1988). Human v e r s u s computerized e v a l u a t i o n of polygraph d a t a i n a

laboratory setting. Journal Pf -, Z2, 291-302,

Kleinmuntz, Be, & Szucko, J. J. (1984a). A f i e l d s tudy of t h e f a l l i b i l i t y of polygraphic l ie de tec t ion . Nature, m, 449-450.

Kleinmuntz, B., 6 Szucko, J. J. (1984b). L i e d e t e c t i o n in a n c i e n t and modern times: A call for contemporary s c i e n t i f i c s tudy. American Ps-, a, 766-776.

Kugelmass, S., & L i e b l i c h , I. (1966). E f f e c t s of realistic stress and procedura l i n t e r f e r e n c e in experimental lis de tec t ion . , T o n o f I?-, UL, 211-216.

Kugelmass, S., L i e b l i c h , I., & Rergman, 2 . (1967). The role of " ly ing" i n psychophysiological de tec t ion . -, 3, 312-315.

Leach, He Me, & Washburn, M. F. (1910). Some tests by t h e a s s o c i a t i o n r e a c t i o n m t h o d of mental diagnosis .

of Ps-, 21, 162-167.

Lee, C. Dm (1953). The of d o f m e -. S p r i n g f i e l d , Ill.: Charles C. Thomas.

L i e b l i c h , I., Ben-Shakhar, G., & Kugelmass, S. (1976). V a l i d i t y of t h e g u i l t y knowledge technique i n a p r i s o n e r s ' sample. Psy-, a, 89-93.

L i e b l i c h , I., Kugelmass, S., & Ben-Shakhar, G. (1970). Ef f i c i ency of GSR d e t e c t i o n of information a s a func t ion of s t imulus set size. -, 6, 601-608.

L i e b l i c h , I., N a f t a l i , G., Shmueli, J., 6 KugelmAss, S. (1974). E f f i c i e n c y of GSR d e t e c t i o n of information with repeated p r e s e n t a t i o n of series of s t i m u l i i n t w o mot iva t ional states. e d P-, B, 113-115.

Luria, A. R . (1932). T h e e of O c o n f l i c t s r ~

ct and (We H. Gantt, Trans.) . New York: Liver igh t .

Lykken, D. T. (1959). The GSR in t h e d e t e c t i o n of g u i l t . Ps-, a, 385.388.

Lykken, D. T. (1960). The v a l i d i t y of t h e g u i l t y knowledge technique: The e f f e c t s of faking. Journalf -, 44, 258-262.

Lykken, D. T. (1972). Range correction appl ied t o hear t rate and GSR da ta . -, 2, 373-382.

Lykken, D. T. (1974). Psychology and the l ie de tec to r indus t ry- arrrericanPs- JLe, 725-7390

Lykken, D. T. (1978). The psychopath and t h e l ie detector . - f l5-, 137-142.

Lykken, D. T. (1979). The detec t ion of deception. m, 86, 47-53.

Lykken, D. T. (1981)- A d : uses and a b w af. New York: McGraw-Hi l l .

Lykken, D. T. (1984). Trial by polygraph. and, Law,, 75-92.

Lykken, D. T. (1991). The l i e d e t e c t o r controversy: A n alternative s o l u t i o n . I n P. K. A c k l e s , J. R. Jennings, & M. G. H. C o l e s (Eds.), jn London : Jessica Kings ley Publ ishers .

Lykken, D. Tw (1998). A t r e m a r Uses and abuses lie detector (2nd ed. ) . New York: Plenum Press.

Lynn, R. (1966). A+-, m a 1 and or- reaction. London: Perganmn Press.

Maltzman, I. J., Gould, J., Narnett, 0. J,, Raskin, D. C., & Wolff, C. (1979). Habituation of t h e GSR and d i g i t a l vasomotor components of t h e o r i e n t i n g r e f l exes as a consequence of t a s k instructions and sex dif ferences .

, Zr 213-2200

Marston, W. M. (1917). Sys to l i c blood pressure symptoms of deception. J o u r n a l o f Ps-, 2, 117- 163-

Marston, W. M. (1920). Reaction-time symptoms of deception. Ps-, 3, 72-87.

Marston, We M. (1925). Negative type reaction-time symptoms of deception. t, 321, 241-247.

Miyake, Y., Mizutani, M., & Yanumura, T. (1993). Event- r e l a t e d p o t e n t i a l s as an i n d i c a t o r of de tec t ing information i n f i e l d polygraph examinations . -, 2.2, 131-149.

Miinsterberg, H. (1908). -the stand. New York: Doubleday.

Nakayama, M., Mizutani , M., & Kizaki, H e (1988). The e f f e c t s of de layed answers on t h e d e t e c t i o n of decept ion .

e Jo-f logy -, 4, 35-40. ( I n Japanese w i t h Engl i sh stlnmrary)

Net te lbeck , T. (1980). F a c t o r s a f f e c t i n g reaction t i m e : Mental retardation, b r a i n damage, and o t h e r psychopathologies . I n A. T. Welford (Eds. ) , Reaction

(pp. 355-401). London: Academic P r e s s .

Orne, M. T., Thackray, R. I., 6 Paskewitz , D. A, (1972). On t h e d e t e c t i o n of decept ion: A model for t h e s t u d y o f p h y s i o l o g i c a l e f f e c t s of psycho log ica l s t i m u l i . I n N. S. G r e e n f i e l d & R. A. Ste rnbach (Eds.), rraadbook of psy- (pp. 743-785). New York: H o l t , Rinehart, and Winston.

Podlesny, J. A,, & Raskin, D. C . (1977). P h y s i o l o g i c a l measures and t h e d e t e c t i o n o f decep t ion .

, 84, 782-7990

Raskin, D. C. (1978) . S c i e n t i f i c assessment of t h e accuracy of d e t e c t i o n o f decept ion: A r e p l y t o Lykken, P-, ,, 143-147.

Raskin, D. C. (1979). O r i e n t i n g and d e f e n s i v e r e f l e x i n the detection of decep t ion . I n H. D. Kilmnel, E. H. van O l s t , & J. F. Orlebeke (Eds . ) , (pp. 587-605). H i l l s d a l e , N. J.: Lawrence Erlbaum.

Raskin, D. C. (1989) . Polygraph t echn iques for t h e d e t e c t i o n of decept ion . I n D. C. Raskin (Eds . ) ,

New York : S p r i n g e r Pub l i sh ing Company.

Raskin, D. C., & Podlesny, J. A. (1979). T r u t h and deception: A r e p l y to Lykken. P a y d m U g i c N B-, 36, 54-59.

R e i d , J. E., & Inbau, F. E. ( 1 9 7 7 ) . (2nd ed.). Baltimore: Will iams & Wilkins.

Rich, G. J. (1926). D r . Marston on d e c e p t i o n types . American Journal of P3-, 3.2, 307-309.

Rosenfeld, J. P., Cantwel l , B., Nasman, V. T., Wojdac, V., Ivanov, S., 6 Mazzeri, L. (1988). A modif ied event- related po ten t i a l -based g u i l t y knowledge test.

N e u r o s c i e n c e , U, 157-1610

Rosenfeld, 30 P., N a s m a n , V. To, Whalen, Rot Cantwell, 8., & Mazzeri, L. (1987). La te vertex positivity in event- r e l a t e d p o t e n t i a l s as a g u i l t y knowledge i nd i ca to r : A new method o f lie de t ec t i on . International J e of Neuroscience, 34, 125-129.

Rosenthal, Ro R., & Rubin, Do Bo (1978) . Interpersonal expectancy e f f e c t s : The f i rs t 345 s t ud i e s . Behavioral and, Sciences,, 377-415-

Runkel, Jo Eo (1936). L u r i a ' s motor ~ t h o d and word association i n t h e s tudy o f deception. of &, J& 23-37.

S a x e , L. (1991). Science and the CQT polygraph: A t h e o r e t i c a l critique. IntearatS-1 and Behavioral, 26, 223-2310

Saxe, L., Dougherty, Do, & C r o s s , T o (1985). The v a l i d i t y of polygraph t e s t i n g : S c i e n t i f i c ana ly s i s and p u b l i c controversy. m, 44, 355-366.

S idd le , D. A. To (1991). Or ient ing , hab i tua t ion , and resource allocation: An a s s o c i a t i v e ana ly s i s . a, a, 245-2590

Thackray, R. I., & Orne, M o To (1968). A comparison of phys io log i ca l i nd i ce s i n d e t e c t i o n of decept ion. a, 4, 329-339.

T h n , H. W. (1982). E f f e c t s of a l t e r e d outcome expectancies stemming from placebo and feedback treatments on t h e v a l i d i t y of t h e g u i l t y knowledge technique. Journal of

Pw-, n, 391-400.

T rov i l l o , P. V. (1939). A h i s t o r y of lie de t ec t i on . Journal . . . . a, 2% 848-881; ul, 104-119.

Vincent, A., & Furedy, J o J. (1992). Electrodermal d i f f e r e n t i a t i o n of decept ion: p o t e n t i a l l y confounding and i n f l uenc ing f a c t o r s . JO- of L, U, 129-1360

Waid, W. M o , Orne, E. C., Cook, M. Ro, & O n e , M. T. (1978). E f f e c t s of a t t e n t i o n , as indexed by subsequent memory, on e lec t rodermal d e t e c t i o n of information. ;Taurnal_of

Ps-, m, 728-733.

Waid, W. M a , Orne, Em C., Cook, M. R., & O r n e , M. To (1981a). Meprobamate reduces accuracy of phys io logica l d e t e c t i o n of decept ion. Science, 212, 71-73.

waid, W. M., Orne, Em C., & Ome, M. T. (1981b) . S e l e c t i v e memory for social information, a l e r t n e s s , and phys io log ica l arousal i n the detection of deception.

P-, 66, 224-232.

Welford, A. T. ( E d . ) . ( 1980) . ti=. London: Academic Press.

Yerkes, Ro M o t & Berry, C. S. ( 1909) . The association reaction method of mental d iagnos i s . -, ZQ, 22-37.

APPENDIX A -

I 111 Dining Room I t e x 13'

APPENDIX A-2

APPENDIX B

The following i n s t r u c t i o n s was presented on a computer screen i n f r o n t of a p a r t i c i p a n t before t h e experiment start. The bordered modules appeared one by one and t h e p a r t i c i p a n t was requ i red to h i t a computer key t o proceed t o t h e next screen. Note t h a t t h e exac t format of t h e i n s t r u c t i o n was d i f f e r e n t due t o t h e s i z e of t h e computer screen.

Thanks f o r coming! The session w i l l start soon. Before s t a r t i n g , I w i l l g ive you some i n s t r u c t i o n s about t h i s experinmnt on behalf of t h e experimenter. If you are not s u r e about my explanat ion , p l ea se ask t h e experimenter anytime. H e can g ive t h e answer for your quest ian.

B i t any key t o proceed, pleasel

This l i e d e t e c t i o n experiment can be divided into three parts. They are

1) a base l ine pe r iod 2 ) reading a crime scenar io , and 3 ) a c t u a l i n t e r r o g a t i o n procedure,

a n d it takes about an hour t o complete.

I H i t any key t o proceed, pleasel I

The base l ine pe r iod w i l l begin now and w i l l t a k e about 5 min . t o complete. This is t o check t h e recording equipment and to record your basic s k i n conductance responses. Some l i g h t s and tones w i l l be present ing dur ing t h i s period. A l l you have to do is ju s t to sit q u i e t l y and re lax . P lease t r y no t t o move your fingers with t h e e l ec t rodes too much.

A f t e r t h e base l ine per iod is over, t h e experimenter w i l l te l l you what to do next.

I f you have any quest ion , please ask t h e experimenter now! I f you are ready, p lease say s o t o t h e e x ~ e r h n t e r l

[The experimenter turned off the computer acreen and left the room to start recording.]

[ A f t e r the baseline period, the experimenter entered the roam and turned on the computer acreen.]

As you a l ready know, t h i s experiment is about l i e de t ec t i on . The room you are now in i s an i n t e r r o g a t i o n r o o m in a police s t a t i o n . H e r e , I would like you t o play the role of a burglar, who a c t u a l l y committed a burg la ry and has been under arrest for that reason.

But you are a tough criminal and you have no t confessed your crime during normal i n t e r r o g a t i o n procedures. Although s e v e r a l i n v e s t i g a t o r s i n t h i s case are convinced t h a t you are t h e burglar, it i s also t r u e t h a t t h e r e is no t enough material evidence t o show t h a t you are gu i l t y .

So, t h e irritated chief investigator decided to make you t a k e a l ie d e t e c t i o n test, and you have agreed. That's why you are here. If you can beat t h i s lie de t ec t i on test, you w i l l be released.

D o you understand your role? If not, p lea se ask t h e experimenter now. Next I'll exp la in t h e crime you committed (I know, I know, you are innocent. But just p lay t h e ro le! ) . You d o n ' t have t o memorize the details. J u s t try t o g rasp t h e situation.

I H i t any key t o proceed, pleasel

The crime concerned he re is, of course, t h e burglary.

The o the r day, a t midnight, somone broke i n t o a house i n c Toronto suburb. A f t e r t h e po l i ce inves t iga t ions , it was revealed t h a t t h e burg la r broke i n t o t h e house and stole something. Fortunately, no one i n t h e family w a s hu r t because they were on a t r i p t o South Flor ida (gorgeous, eh?). From t h e way in which t h e burglary had been ca r r i ed out , the pol ice i d e n t i f i e d and arrested you as t h e burglar . You had three records of burglary before.

But you were smart enough not t o leave any material evidence t h i s time. As I s a i d before, several i nves t iga to r s are convinced t h a t you are the burglar , but it i s also true t h a t they have not enough evidence.

As I said before, you w i l l be re leased i f you can b e a t t h e following l i e de t ec t ion test. If you f a i l , you w i l l s t i l l be kept in custody. Moreover, the r e s u l t of t h e test w i l l be used i n your t r i a l as an evidence.

t r y to beat the fol lawing test!!!

Next, I ' 11 explain the rest of experimental procedures. If you have any quest ion about t h e ins t ruc t ions , p lease f e e l free t o ask t h e sxperimenter a t any t i m e .

B i t any key t o proceed, please!

Afterward, I w i l l p resen t a scenar io t h a t depicted t h e crime you had committed. Please read t h e scenar io c a r e f u l l y and fol low the i n s t r u c t i o n i n it. During t h e course of reading, I w i l l a sk you t o make your own dec is ion t w i c e , t h a t is to say, t o choose t h e spot where you would have broken i n t o t h e house and the it- you would have s t o l e n as a burglar . But keep your choice t o yourself and d o n ' t te l l t h e experimenter about the spo t and t h e item you choose because t h e experimenter 's mission is t o i d e n t i f y them based on your physiological recording.

H i t any key to proceed, p lease l Following t h e scenar io reading, t h e in t e r roga t ion

w i l l start. During t h e in t e r roga t ion period, 1'11 present one quest ion a t a time a t t h e c e n t e r of my screen. The quest ion looks like t h i s ( h i t Y key on t h e keyboard! ) :

D i d YOU break i n throuah the bdroa?

[ A t t h e same t ime, t h i s quest ion was a l s c presented a u r a l l y by computer synthesized voice.]

Surpr ised? I can speak Engl ish and I t h i n k my Engl ish is better than t h e experimenter 's one. Agree?

Anyway, when each quest ion is asked, you must always reply by saying (orally),

innaediately a f t e r t h e end of ques t ion, and h i t the mpace key at the same the. Your t a s k i s t o deny every ques t ion i n a same way.

Please h i t any key t o proceed1

Now, let 's have some p r a c t i c e . P lease keep in mind t h a t you must respond a s soon as poss ib le af ter you hear t h e quest ion. Also, d o n ' t f o r g e t t o h i t t h e space key a t t h e saxm tilru?.

If YOU are ready, lease h i t any key!

[Here, the par t ic ipant was given some practice. I f the pa r t i c i pan t ' s react ion time fe l l between 100 and 1000 m s e c , t h e computer s a id "Good!" and then prompted t h e par t ic ipant t o proceed t o t h e next screen. If t h e reaction time was not proper one, o r s /he did not give his o r her oral answer, the computer or t he experimenter ins t ructed her/him so and gave more pract ice . ]

D i d you break in through t h e pa t i o?

D i d you steal t h e rad io?

Good11 Let's proceed t o t h e next i n s t r u c t i o n by h i t t i n g any key!

During t h e i n t e r roga t ion , 1'11 ask you 1 0 d i f f e r e n t ques t ions and each ques t i on w i l l be repeated 4 t imes. So you have t o respond to 40 ques t ions dur ing t h i s period.

There are seve ra l seconds between quest ions and you might become irritated. But p lease s t a y c a l m . That might be a tactic of t h e experimenter.

During t h e i n t e r roga t ion , p l e a s e r e s t r a i n from ex t ens ive body movements, e s p e c i a l l y l e f t hand f i n g e r mvenen t l I f you don ' t do so, the record of your skin conductance response w i l l be d i s t o r t e d and you g ive an impression t h a t you use such stratecry to avoid detec t ion.

>

That ' s a l l t h e i n s t r u c t i o n s I can give you now. If t h e r e ' s something you are n o t s u r e about, please ask t h e experimenter now. OK?

I f you're ready, le t 's proceed to t h e crime s c e n a r i o l

P l e a s e h i t any key t o proceed, please! I

SCBDTARIO It was Saturday midnight i n late win te r and you

were on your way t o commit a burglary . The t a r g e t w a s a house in a Toronto suburb. The house attracted your a t t e n t i o n because it was off the msin road, and you knew t h a t t h e r e was no t raff ic a t t h a t time of night . Also, you knew t h e occupants of the house had been away on vacat ion. So your work t h a t n i g h t looked easy.

You drove your car behind a stand of trees, where it was hidden from view, and turned o f f t h e engine, l i s t e n i n g a t t e n t i v e l y f o r any sounds t o make s u r e t h a t you were alone. Nothing d i s t u r b e d t h e s i l e n c e a p a r t f r o m a lone s q u i r r e l t h a t you seemed t o have waken up. As it ran up t h e n e a r e s t tree you p u t your g loves on and began to approach t h e house.

H i t any key t o proceed, pleasel

You walked c a u t i o u s l y around t h e house whi le you tried t o f i g u r e o u t where it would be e a s i e s t to break into and soon you decided on t h e spot.

W a s t h e spot 1 ) Entrance, 2 ) ?dip roam, 3 ) Garage, 4 ) f i tchen, or 5 ) Living roa?

P l e a s e choose just one spot by h i t t i n g a corresponding numerical key on t h e computer keyboard.

OK, you chose [ s p o t ] , r i g h t ? L e t ' s r e t u r n t o t h e s c e n a r i o now by h i t t i n q any kevl

[If the participant belonged to the experimental group, then s/he received the following SCENARIO (a). If the participant belonged to the control group, then s/he received the following SCENARIO (b).]

SCRUMUO (a-1) Breaking in was even easier than you had expected

bu t s ea r ch ing w i th your f l a s h l i g h t <here did& s e e m t o be anything worth t a k i n g on t h e ground f l o o r , so you proceeded to t h e second floor. It seemed t h a t you were going t o have bad luck t h a t n i g h t as nothing worth stealing tu rned up u n t i l you, suddenly, not iced a c h e s t of drawers i n t h e master bedroom. You approached t h e c h e s t and pu l l ed out t h e t o p drawer, bu t t h e r e was nothing to be found u n t i l you inspected the last drawer. There, lying i n the corner, was the worthy i t e m . Then you reached for t h e i t e m .

Was the item a 1) C a m r a , 2 ) Bracelet, 3 ) Pusme, 4 ) Ring, or 5) Watch?

Plea se choose j u s t one i t e m now by h i t t i n g a corresponding numerical key on t h e computer kevboard .

[when the participant hit the numerical key, the computer produced a siren-like sound, The sound continued until the participant hit any key again following the instruction given in the next screen.]

Damn it! ! The alarm!! I must g e t o u t of here now1 l

You grabbed t h e i t e m , p u t it i n your pocket, and r a n away.

(*PLEASE HIT ANY KEY TO TERMINATe THE SOUND*)

Luckily, you managed t o g e t away before t h e p o l i c e arrived.

Please h i t any key to proceed, please!

B C l r r n X O (b) B r e a k i n g in was even easier than you had expected

but aearchhg with your f l a s h l i g h t <here didn I-t seem t o be anything worth taking on the ground floor, so you proceeded to t h e second f loor . It seemed t h a t you were going to have bad luck t h a t night as nothing worth s t e a l i n g turned up u n t i l you, suddenly, noticed a chest of drawers in t h e master bedroom. You approached t h e ches t and pulled ou t t h e t o p drawer, bu t t h e r e was nothing to b e found u n t i l you inspected the last drawer. rhere, lying i n the corner, wag t h e worthy i t e m . You grabbed it and put it i n your pocket. Then you can downstairs, and l e f t the house.

Was the i t e m a 1) Bsacelet, 2 ) Cansa, 3 ) Purse, 4 ) Ring, or 5 ) Watch?

Please chooae just one item now by h i t t i n g a zorresponding numerical key on t h e computer keyboard.

Please h i t any key to proceed, please!

So, t h a t ' s t h e end of s t o r y . During t h e burglary, you entered t h e house from [ the spot t h e p a r t i c i p a n t would choose] and stole [ the i t e m s / h e would choose], r i g h t ?

And now you're i n an in t e r roga t ion room. Soon, t h e in te r roga t ion w i l l start. Your task is to beat t h e polygraph. Remember?

You have t o deny every quest ion and h i t t h e space key after you hear t h e question.

Are you ready? When you h i t t h e s p x e key, t h e in te r roga t ion w i l l start.