explicit memory bias

8/3/2019 Explicit Memory Bias

http://slidepdf.com/reader/full/explicit-memory-bias 1/12

BEHAVIOR THERAPY 31,745-756,2000

E x p lic it M e m o r y B i a s fo r T h r e a t W o r d s inG e n e r a l i ze d A n x ie t y D is o r d e r

BRUCE H . FRIEDMAN

Virginia Polytechnic Institute and State University

JULIAN E THAYER

University of M issouri-Columbia

THOMAS D. BORKOVEC

The Pennsylvania State University

Although findings of an implicit memory bias for threat words in generalized anxi-

ety disorder (GAD) are fairly robust, the data regarding an explicit bias in this disor-

der are less consistent. This issue was investigated in the context of two studies

directed primarily at the examination of attentional and physiological underpinnings

of GAD. In these experiments , GAD clients and nonanxious control participants (35

and 29 in Study 1, and 22 and 31 in Study 2, respectively) engaged in an S1-$2 con-

ditioning procedure that involved the presentation of a series of neutral stimuli(colored dots) paired with threat and nonthreat words , followed by a free recall test.

Instructions were to simply look at the dot and read the word silently. A free recall

task was administered at the end of each experimental session. Contrary to previous

trends in the literature, a marked bias in the GAD group toward recall of the threat

words emerged in both studies. These results are considered in the light of method-

ological differences with previous research, information processing characteristics

of GAD, and the role of physiological assessment in cognitive studies of anxiety.

I n f o r m a t i o n p r o c e s s i n g a p p r o a c h e s t o a n x i e t y h a v e y i e l d e d n u m e r o u s

ins igh t s in to the cogn i t ive mechan isms tha t opera te in genera l i zed anx ie ty

d i so rder (GA D) . In pa r ti cu la r , examina t ion o f me m ory b iase s fo r d i so rder -

cong ruen t in fo rmat ion sugges t s tha t charac te ri s ti c cogn i t ive s ty les can d i s tin -

Preparation of this manuscript was supported in part by National Institute of Mental Health

Grant MH-39172 to the third author. The authors would like to thank Mary Borkovec, Holly

Hazlett-Stevens, Jim Lyonfields, Katie Peasley, and the late Silvia Molina for assistance in data

collection and quantification. These data were collected at the Stress and Anxiety Disorders

Institute, Department of Psychology, The Pennsylvania State University.

Address correspondence to Bruce H. Friedman, Department of Psychology, Virginia Polytech-

nic Institute and State University, Blacksburg, VA 24061--0436; e-mail: [email protected].

745 005-7894/00/07454)75651.00/0Copyright 2000 by Association or Advancementof BehaviorTherapy

All rights for reproduction n any form reserved.



746 FRIEDMAN ET AL.

g u i s h a m o n g v a r i o u s p s y c h o p a t h o l o g i e s . F o r e x a m p l e , a n i m p l i c i t m e m o r yb i a s ( e n h a n c e m e n t o f s t i m u l u s r e c o g n i t i o n b y p r i o r s t i m u l u s e x p o s u r e o r" p r i m i n g , ' w i t h o u t c o n s c i o u s r e c o l l e c t i o n o f t h e e x p o s u r e ; s e e S q u i r e , 1 9 9 2)

h a s b e e n t y p i c a l l y as s o c i a t e d w i t h a n x i e t y , a n d a n e xp l i c i t m e m o r y ( a v a i l a b l eto c onsc ious re c a l l) b i a s ha s be e n fou nd m ore c ha ra c t e r i st i c o f de pre s s ion ( seeW i l li a m s , W a tt s, M a c L e o d , & M a t h e w s , 1 99 7, f o r re v i ew ) . I m p l i c it m e m o r yp r o c e s s e s a c t i v a t e s t o r e d i n f o r m a t i o n , t h e r e b y i m p r o v i n g i t s a c c e s s i b i l i t y ,

t hough no t ne c e ssa r i l y a f fe c t ing i t s d i re c t r e t r i e va b i l i t y (G ra f , 1994) . Con-v e r s e ly , e x p l i c it m e m o r i e s i n v o l v e c o n s c i o u s , d e li b e r a te r e c a ll o f i n f o r m a t i o n

t h a t w a s e l a b o r a t e d a t t h e t i m e o f e n c o d i n g , a n d a re t h e r e f o r e m o r e a v a i l a b led u e t o e m b e l l i s h m e n t f r o m c o n t e x tu a l c u es . A n x i e t y is m a r k e d b y a n o n c o n -

sc ious , a u tom a t i c , p re -a t t e n t ive b i a s tow a rd th re a t c ue s (M a the w s , 1990) t ha tm a y p r i m e s u c h i n f o r m a t i o n i n i m p l i c i t m e m o r y t e s t s . H o w e v e r , t h i s d e f e n -s i v e a t t e n t i o n a l m e c h a n i s m t h w a r t s f u r t h e r p r o c e s s i n g o f a n x i e t y - p r o v o k i n gs t i m u l i , a n d s o n o e x p l i c it m e m o r y b i as a p p e a r s f o r s u c h m a t e r i a l. I n c o n t r a s t,

d e p r e s s i o n i s c h a r a c t e r i z e d b y c o n s c i o u s e l a b o r a t i o n o f s a d m a t e r i a l , w h i c hinc re a se s i ts a v a i l a b i l i ty fo r e x p l i c i t, d i re c t e d re c a l l.

H o w e v e r , t h e s e s p e c i f i c m e m o r y e f f e c t s i n a n x i e t y m a y n o t g e n e r a l i z ea c r o s s d i a g n o s t i c c a t e g o r i e s . F o r e x a m p l e , a l t h o u g h t h e p r e d i c t i o n o f a n

i m p l i c i t b u t n o t e x p l i c i t m e m o r y b i a s f o r d i s o r d e r - c o n g r u e n t m a t e r i a l h a sb e e n r e p li c at e d in G A D ( M a c L e o d & M c L a u g h l i n , 1 9 9 5) , o t h er s h a v e f o u n dbo th impl i c i t a nd e xp l i c i t me mory b i a se s fo r r e l e va n t s t imul i i n pa n ic d i so r -

d e r ( C l o i tr e & L e i b o w i t z , 1 99 1 ) . A d i r e c t c o m p a r i s o n b e t w e e n p a n i c d i s o r d e ra n d G A D r e v e a l e d a n e x p l i c i t m e m o r y b i a s i n t h e f o r m e r , b u t n o t t h e l a t t e r

( B e c k e r , R o t h , A n d r i c h , & M a r g r a f , 1 9 9 9 ) . B e c k e r e t a l. s u g g e s t e d t h a t m e t h -o d o l o g i c a l i n c o n s i s t e n c i e s a cr o s s s t u d i e s m i g h t a c c o u n t f o r t h e s e d i s c r e p a n t

m e m o r y e f f e c t s i n t h e a n x i e t y l i t e r a t u r e , a n d a d v o c a t e d t h e c o m b i n a t i o n o finc ide n ta l l e a rn ing a nd f re e re c a l l a s t he op t ima l pa ra d igm fo r de t e c t ingm e m o r y b i a s e s i n c l in i c a l a n x ie t y . T h e y f u r t h e r p r o p o s e d t h a t t h i s p a ir i n g i s

e n h a n c e d w i t h c o m p a t i b l e l e a r n i n g a n d r e tr ie v a l ta s k s ; t h a t is , b o t h s h o u l d b ee i t h e r c o n c e p t u a l o r p e r c e p t u a l ( e .g . , E y s e n c k & B y r n e , 1 9 9 4) .

A n o p p o r t u n i t y t o m e e t t h e s e s t a n d a r d s a n d t h u s c o n c e p t u a l l y r e p l i c a t eB e c k e r e t a l . ' s ( 1 9 9 9 ) i n v e s t i g a t i o n o f e x p l i c i t m e m o r y b i a s f o r t h r e a te m e r g e d i n tw o o f o u r o n g o i n g s t u d ie s t h a t w e r e d i r e c t e d p r i m a r i l y a t at te n -t i o n a l a n d p h y s i o l o g i c a l e l e m e n t s o f G A D . A n S 1 - $ 2 p a r a d i g m , w h i c he n ta i l s t he p re se n ta t ion o f a s e r ie s o f pa i re d s t imul i s e pa ra t e d b y a f i xe d in te r -s t imu lus i n t e rva l (B oh l in & K je lbe rg , 1979) , w a s us e d in t he se tw o s tud ie s t oe x a m i n e h i g h e r o r d e r c o n d i t io n i n g t o t h re a t in G A D c l ie n ts a n d m a t c h e d c o n -t ro l g roups . In t he f i r s t s tudy , a c o lo re d d o t (S 1 ) w a s c on s i s t e n t ly pa i re d w i the i the r t h re a t o r non th re a t w ords ($2) ove r mul t ip l e t r i a l s ( s e e Tha ye r , F r i e d -

m a n , B o r k o v e c , J o h n s e n , & M o l i n a , 2 0 0 0 , f o r d e t a i l s ) . I n d i v i d u a l s w e r e

ins t ruc t e d to s im ply look a t t he do t a nd the n re a d the w ord s i l e n tly . Th e se c -o n d s t u d y w a s a n e x a c t r e p l ic a t io n o f t h e f i rs t: th e p h y s i o l o g i c a l a n d a t te n -t i o n a l d a t a f r o m E x p e r i m e n t 2 h a v e n o t y e t b e e n r e p o r t e d ( T h a y e r , F r i e d m a n ,& B o r k o v e c , 2 0 0 0 ) . T o a d d r e s s t h e i s s u e o f a p o t e n t i a l m e m o r y b i a s , a f r e e



MEMORY BIAS IN GE NER ALI ZED ANXIETY DISORDER 747

r e c a ll t e s t o f t h e s t im u l u s w o r d s w a s g i v e n f o l l o w i n g t h e c o n d i t i o n i n g p r o c e -

d u r e . T h u s , t h e p a i r i n g o f th e S 1 - $ 2 p r o c e d u r e ( a n i n c i d e n ta l l e a r n i n g t a s k )

a n d f r e e r e c a l l ( b o t h t a s k s a r e a l s o c o n c e p t u a l ) , u t i l i z e d i n b o t h s t u d i e s , c o n -

f o r m s t o t h e r e c o m m e n d a t i o n s o f B e c k e r e t al . ( 1 9 9 9 ) . Im p o r t a n t l y , h o w e v e r ,t h e c o n d i t i o n i n g t a s k i n v o l v e d e x t e n d e d e x p o s u r e ( 8 s e c o n d s ) t o t h e t h r e a t

w o r d s , w h i c h m a y b e m o r e l i k e l y t o e l i c i t a n e x p l i c i t m e m o r y b i a s t h a n t h e

b r i e f e x p o s u r e t i m e s t h a t t y p i f y m o s t s t u di e s ( e . g ., S t r o o p p a r a d i g m s ) o f t h is

p h e n o m e n o n ( B o r k o v e c , R a y , & S t o b e r , 1 9 9 8 ). F u r t h e r m o r e , r e t e n t i o n is

g e n e r a l l y e n h a n c e d f o r e m o t i o n a l l y a r o u s i n g s ti m u l i ( M c G a u g h , 1 9 9 2 ) , a n d

t h r e a t w o r d s w o u l d p r e s u m a b l y b e e s p e c i a l l y a r o u s i n g t o G A D c l ie n t s. B a s e d

o n t h e s e n o t i o n s , t h e f o l l o w i n g h y p o t h e s e s w e r e g e n e r a t e d a n d t e s t e d i n t h e

p r e s e n t s t u d ie s : ( a ) G A D c l ie n t s w i ll r e c a ll m o r e t h r e a t t h an n o n t h r e a t w o r d s ,

( b ) t h e s e i n d i v i d u a l s w i l l r e c a l l m o r e t h r e a t w o r d s w h e n c o m p a r e d t o a

m a t c h e d c o n t r o l g r o u p , ( c ) r e c a l l f o r t h r e a t w o r d s w i l l b e g r e a t e r t h a n n o n -

t h r e a t w o r d s i n th e c o n t r o l g r o u p , a s w e l l , b e c a u s e o f th e a r o u s i n g n a t u r e o f

t h r e a t w o r d s , a n d ( d ) t h e re w i l l b e n o d i f f e r e n c e s b e t w e e n t h e g r o u p s o n

r e c a l l o f n o n t h r e a t w o r d s .

E x p e r i m e n t 1

Method

Participants. T h i r t y -f i v e t r e a tm e n t - s e e k in g G A D c l ie n ts a n d 2 9 m a t c h e d

c o n t r o l p a r ti c i p a n ts c o m p l e t e d t h e l a b o r a t o r y s e s si o n . A g e n c y - r e f e r r e d a n ds e l f - re f e r r e d c l ie n t s w e r e f ir st g iv e n a 3 0 - m i n u t e p h o n e i n t e r v ie w b y c l in i c a l

g r a d u a t e s t u d e n t a s se s s o rs t o d e t e r m i n e w h e t h e r G A D w a s t h e li k e l y d i a g n o -

s i s . S u b s e q u e n t l y , t h e a s s e s s o r c o n d u c t e d a d i a g n o s t i c i n t e r v i e w u s i n g t h e

A n x i e t y D i s o r d e r I n te r v ie w S c h e d u l e - R e v i s e d ( A D I S - R ; D i N a r d o & B a r l ow ,

1 9 8 8 ) . C l i e n t s w e r e a d m i t t e d t o a t h e r a p y t ri a l i f t h e y m e t c r i t e r i a f o r a p r i n c i -

p a l DSM-III-R ( A m e r i c a n P s y c h i a t r i c A s s o c i a t i o n , 1 9 8 7) d i a g n o s i s o f G A D

w i t h a n a s s e s s o r s e v e r i t y ra t in g o f 4 (moderate anxiety) o r g r e a t e r o n a 0 - t o -

8 - p o i n t s e v e r i ty s c a l e , a n d i f t h e y d i d n o t m e e t c r i t e ri a f o r p a n i c d i s o r d e r w i t h

o r w i t h o u t a g o r a p h o b i a , o r g a n i c b r a i n s y n d r o m e , s u b s ta n c e a b u s e , o r m e d i c a l

c o n d i t i o n s t h a t m a y c o n t r i b u t e to a n x i e ty . T h e A D I S - R w a s c o n d u c t e d a s e c -o n d t i m e b y a P h . D . c l i n i c a l p s y c h o l o g i s t . It w a s r e q u i r e d t h a t b o t h d i a g n o s t i c

i n t e r v i e w e r s a g r e e t h a t t h e c r it e r ia w e r e m e t . C o n t r o l s u b j e c ts w e r e r e c r u i t e d

b y n e w s p a p e r a d v e r t i se m e n t s a n d w e r e a s s e s s e d b y th e p h o n e i n t e r v i e w a n d a

s i n g le a d m i n i s tr a t io n o f t h e A D I S - R c o n d u c t e d b y o n e o f th e c l in i c a l a ss e s -

s o rs . T h e s e i n d i v id u a l s w e r e i n c l u d e d i n t h e s t u d y i f t h e y d i d n o t m e e t d i a g -

n o s t i c c r i t e r i a f o r a n y d i s o r d e r a t e v e n m i l d s e v e r i t y l e v e l s a n d i f t h e y

r e p o r te d n o p r i o r h is t o ry o f p s y c h o p h a r m a c o l o g i c a l o r p s y c h o l o g i c a l t re a t-

m e n t o f a n y k in d . P h y s i o l o g i c a l d a t a f r o m t h is s t u d y a r e r e p o r t e d i n T h a y e r e t

a l . ( 2 0 0 0 ) .T h e d i st r ib u t i o n o f g e n d e r a c ro s s g r o u p s w a s 2 2 w o m e n a n d 1 3 m e n f o r

G A D a n d 1 8 w o m e n a n d 11 m e n f o r c o n t ro l . T h e d i st r ib u t i o n o f r a c e w a s 3 1

C a u c a s i a n , 1 A f r i c a n A m e r i c a n , 2 H i s p a n i c , a n d 1 M i d d l e E a s t e r n f o r t h e



748 F R I E D M A N E T A L .

T A B L E 1

C O M O R B I D D I A G N O S E S F O R G A D C L IE N T S

E x p e r i m e n t I E x p e r i m e n t 2

S o c i a l p h o b i a 1 9 1 5

S p e c i f i c p h o b i a 1 2 3

A g o r a p h o b i a 3 2

M a j o r d e p r e s s i o n ( r e c u r re n t ) 3 0

M a j o r d e p r e s s i o n 2 0

D y s t h y m i a 1 2

M a j o r d e p r e s s i o n ( p a r ti a ll y r e m i t t e d ) I 1

O b s e s s i v e - c o m p u l s i v e d i s o rd e r 1 0

P o s t t r a u m a t i c s t re s s d i s o r d e r 1 0

S e a s o n a l a f f e c t i v e d i s o r d e r 1 0

G A D g r o u p , a n d 2 6 C a u c a s ia n , 1 A f r i c a n - A m e r i c a n , 1 H i s p a n i c , a n d 1 M i d d l e

E a s t e r n f o r t h e c o n t r o l g r o u p . A v e r a g e a g e s o f t h e c l ie n t s a n d c o n t r o l s w e r e

3 6 . 9 (SD = 1 1 . 8 ) a n d 3 3 . 8 (SD = 1 0 .9 ) y e a r s , re s p e c t i v e l y , a n d a v e r a g e y e a r s

o f e d u c a t i o n w e r e 1 5.7 (SD = 2 .6) and 16 .1 (SD = 2 . 3 ) , r e s p e c t i v e l y . T h e

g r o u p s d i d n o t d i f f e r s i g n i f i c a n t l y o n a n y o f t h e s e v a r i a b l e s . T h e a v e r a g e

d u r a t i o n o f t h e c l i e n t s ' d i s o r d e r w a s 1 2 .5 y e a r s (SD = 1 2 .6 ) . S e v e n t y - s e v e n

p e r c e n t h a d a t l e a s t o n e c o m o r b i d d i a g n o s i s ( s e e T a b l e 1 ) a n d 5 w e r e t a k i n g

p s y c h o t r o p i c m e d i c a t io n ~ a t t h e t i m e o f t h e s e ss i o n.

A t t h e e n d o f th e d i a g n o s t ic i n t e rv i e w u s i n g t h e A D I S - R , t h e H a m i l t o n

A n x i e t y R a t i n g S c a l e ( H A R S ; H a m i l t o n , 1 9 6 0 ) a n d t h e H a m i l t o n R a t i n g

S c a l e f o r D e p r e s s i o n ( H R S D ; H a m i l t o n , 1 9 5 9 ) w e r e a l so a d m i n i s t e r e d . I n a

s e p a r a t e s e l f - r e p o r t s e s s i o n , c li e n t s ( b e f o r e t h e r a p y b e g a n ) a n d c o n t r o l s c o m -

p l e t e d t h e S t a t e -T r a i t A n x i e t y I n v e n t o r y - T r a i t ( S T A I ; S p i e lb e r g e r , G o r s u c h ,

L u s h e n e , V a g g , & J a c o b s , 1 9 8 3) ; th e R e a c t i o n s t o R e l a x a t i o n a n d A r o u s a l

Q u e s t i o n n a i r e , a f a c t o r a n a l y t i c a l l y d e r i v e d m e a s u r e o f f e a r o f r e l a x a t i o n

( R R A Q ; H e i d e & B o r k o v e c , 1 9 8 3) ; t h e P e n n S t a t e W o r r y Q u e s t i o n n a i r e

( P S W Q ; M e y e r , M i l le r , M e t z g e r , & B o r k o v e c , 1 9 9 0 ) , a m e a s u r e o f w o r r yt h a t d i s t in g u i s h e s G A D f r o m a ll o t h e r a n x i e ty d i s o rd e r s ( B r o w n , A n t o n y , &

B a r l o w , 1 9 9 2) ; a n d t h e B e c k D e p r e s s i o n I n v e n t o r y ( B D I ; B e c k , W a r d , M e n -

d e l s o n , M o c k , & E r b a u g h , 1 9 6 1 ).

T h i s r e s e a r c h w a s a p p r o v e d b y t h e I n s t i t u t i o n a l R e v i e w B o a r d a n d

i n f o r m e d c o n s e n t w a s o b t a i n e d f r o m e a c h p a r t i c i p a n t p r io r t o th e s t a rt o f t h e

e x p e r i m e n t .Procedure. F u l l d e t a i l s o n t h e S 1 - $ 2 t a s k a n d p h y s i o l o g i c a l r e c o r d i n g

p r o c e d u r e c a n b e f o u n d i n T h a y e r e t a l . ( i n p r e s s ) ; i n c l u d e d h e r e i s a n o v e r -

v i e w o f t h e S 1 - $ 2 p r o c e d u r e a n d d e t a i l s o f th e f r e e r e c a ll t es t . E a c h p a r t ic i -

p a n t r e c e i v e d a t o u r o f t h e l a b o r a t o r y a n d a d e s c r i p t i o n o f t h e r e c o r d i n g m e t h -

O n e w a s t a k i n g P r o z a c , 2 w e r e t a k i n g h y p n o t i c - s e d a t i v e s , 1 w a s t a k i n g L i s i n o p r il ( f o r h i g h

b l o o d p r e s s u r e ) , a n d 1 w a s t a k i n g S y n t h r o i d ( a t h y r o i d m e d i c a t i o n ) .



MEMORY BIAS IN GENERALI ZED ANXIETY DISORDER 749

o d s a n d t a s k s p r i o r t o t h e a c t u a l s e s s i o n . A t t h e e x p e r i m e n t a l s e s s i o n a n d a f t e r

e l e c t r o d e a t t a c h m e n t , t h e p a r ti c i p a n t w a s s e a t e d i n a r e c l i n e r c h a i r i n a s m a l l

s o u n d - a t t e n u a t e d r o o m a d j a c e n t t o t h e e q u i p m e n t r o o m a n d l e f t a l o n e w i t h

d o o r c l o s e d ; th e e x p e r i m e n t e r c o m m u n i c a t e d w i t h th e p a r t ic i p a n t v i a in t e r-c o m . T h e i n i t i a l p h a s e o f t h e e x p e r i m e n t i n v o l v e d p h y s i o l o g i c a l r e c o r d i n g

d u r i n g p e r i o d s o f q u i e t r e s t i n g , s e l f - r e l a x a t i o n , a n d w o r r y i n g ( s e e T h a y e r ,

F r i e d m a n , & B o r k o v e c , 1 9 9 6 ). A f t e r a f in a l 5 - m i n u t e b a s e l i n e , t h e S 1 - $ 2

t a s k w a s i n i t ia t e d , w h i c h i n v o l v e d t h e p r e s e n t a t i o n o f a c o l o r e d d o t ( S 1 ) d i s -

p l a y e d a t t h e c e n t e r o f a c o m p u t e r m o n i to r . T h e c o l o r o f th e d o t ( y e l lo w o r

g r e e n ) w a s c o n s i s t e n t l y p a ir e d w i t h e i t h e r t h r e a t o r n o n t h r e a t w o r d s ( $ 2 ) ; t h is

a s s o c i a t i o n w a s c o u n t e r b a l a n c e d a c r o s s s u b j e c t s w i t h i n b o t h G A D a n d c o n -

t r o l g r o u p s . T h i s c o n t i n g e n c y w a s n o t m a d e e x p l i c i t , w h i c h a l l o w e d f o r t h e

a s s e s s m e n t o f h i g h e r o r d e r c o n d i t i o n i n g . T h e i n s t r u c ti o n s s i m p l y r e q u i r e d

t h a t e a c h w o r d b e r e a d s i le n t ly a s i t a p p e a r e d o n t h e s c r e e n . T h e S 1 a n d $ 2

s t i m u l i w e r e s e q u e n t i a l l y p r e s e n t e d f o r 8 s e c o n d s e a c h , w i t h a n i n t e r t r i a l

i n t e r v a l o f 3 0 s e c o n d s . A t o t a l o f 2 0 t r ia l s ( 1 0 t h r e a t , 1 0 n o n t h r e a t ) w a s p r e -

s e n t e d . A s i n g l e o r d e r w a s u s e d w i t h a l l p a r t i c i p a n t s ; t h e o r d e r o f t h e w o r d s

h a d b e e n r a n d o m l y d e t e r m i n e d b e f o r e t h e e x p e r i m e n t , w i t h t h e c o n s t r a i n t

t h a t n o m o r e t h a n 2 c o n s e c u t i v e t r i a l s c o n t a i n w o r d s o f o n e t y p e . T h e 2 0

w o r d s w e r e t a k e n f r o m M a t h e w s a n d M a c L e o d ( 1 9 86 ) . F o l l o w i n g t h e S 1 - $ 2

p r o c e d u r e , s u b j ec t s w e r e a s k e d t o w r it e d o w n a s m a n y w o r d s f r o m t h e p r e v i-

o u s t a sk t ha t t h e y c o u l d r e m e m b e r . T h e n u m b e r o f c o r re c t l y r e c a ll e d t h r ea t

a n d n o n t h r e a t w o r d s s e r v e d a s t h e d e p e n d e n t v a r ia b l e .

Experiment 2

Method

Participants an d procedure. P a r t i c ip a n t s w e r e s e l e c t e d a l o n g t h e s a m e c r i -

t e r ia a s d e s c r i b e d i n E x p e r i m e n t 1 . T h e d i s t ri b u t io n o f g e n d e r a c r o s s g r o u p s

w a s 15 w o m e n a n d 7 m e n f o r G A D a n d 2 2 w o m e n a n d 9 m e n f o r t he c o n tr o l

g r o u p . T h e d i s t r ib u t i o n o f ra c e w a s 1 8 C a u c a s i a n , 1 A f r i c a n A m e r i c a n , 2 H i s -

p a n i c , a n d 2 I n d i a n f o r t h e G A D g r o u p , a n d 2 6 C a u c a s i a n , 1 A f r i c a n A m e r i -

c a n , 2 H i s p a n i c , 1 I n d i a n , a n d 1 A s i a n f o r t h e c o n t r o l g r o u p . A v e r a g e a g e s o f

t h e c l ie n t s a n d c o n t r o l s w e r e 3 5 . 8 1 (S D = 1 2 . 1 ) an d 3 9 . 6 0 (SD = 1 3 . 2 ) y ea r s ,

r e s p e c t i v e l y , a n d a v e r a g e y e a r s o f e d u c a t i o n w e r e 1 5 .9 (S D = 2 . 3 ) an d 1 6 . 8 0

(S D = 2 . 2 ) , r e s p e c t i v e l y . T h e g r o u p s d i d n o t d i f f e r s i g n i f i c a n t ly o n a n y o f

t h e s e v a r i a b le s . T h e a v e r a g e d u r a t i o n o f t h e c l i e n t s ' d i so r d e r w a s 1 0 .9 y e a r s

(S D = 9 . 8 ) . E i g h t y - s i x p e r c e n t h a d a t l e a s t o n e c o m o r b i d d i a g n o s i s ( s e e

T a b l e 1 ) a n d 2 w e r e t a k in g p s y c h o t r o p i c m e d i c a t i o n 2 a t th e t i m e o f t h e s e s -

s i o n . T h e G A D c l i e n t s a n d c o n t r o l p a r t i c i p a n t s c o m p l e t e d t h e s a m e s e l f -

r e p o r t m e a s u r e s o f a n x i e t y a n d d e p r e s s i o n t h a t w e r e a d m i n i s t e r e d in E x p e r i -

m e n t 1 ( s ee T a b l e 2 fo r m e a n s c o r e s ).T h e i n i ti a l p r o c e d u r e , w h i c h i n v o l v e d p h y s i o l o g i c a l r e c o r d i n g d u r i n g p e r i -

2 One was taking Xan ax and 1 was taking Buspar.



750 FRIEDMAN ET AL.

T A B L E 2

G A D CLIENT AND CONTROL SCORES ON SELF-REPORT MEASURES OF

ANXIETY AND DEPRESSION

Experiment 1 Experiment 2

GAD Control GAD Control

Mean SD Mean SD Mean SD Mean SD

BDI 18.12 8.03 1.21 1.70 16.24 7.76 1.84 4.19

HARS 24.35 6.31 2.53 1.98 23.51 6.31 2.82 2.23

HR SD 14.10 7.32 1.47 1.27 10.26 4.89 1.29 1.21

RRAQ 28.15 7.12 12.92 3.99 28.29 6.54 13.10 4.47

STAI 59.03 7.56 27.69 4.89 55.82 8.23 25.45 5.43

PSWQ 68.58 7.72 28.07 6.31 67.05 8.36 28.55 9.41

Note. BDI - Beck Depress ion Inventory; HARS = Hamilton Anxiety Rating Scale; HRSD =

Hamilton Rating Scale for Depression; RRAQ = Reactions to Relaxation and Arousal

Questionnaire; STAI = State-Trait Anxiety Inventory-Trait: PSWQ = Penn State

Worry Questionnaire.

o d s o f q u ie t r e s t, s e l f - re l a x a t io n , a n d w o r r y , a n d s u b s e q u e n t S l - S 2 a n d f r e e

r e c a ll p r o c e d u r e s , w e r e i d en t ic a l to E x p e r i m e n t 1.

Results

Statis t ical An alyses

A s a m a n i p u l a t i o n c h e c k , d i f f e r e n c e s b e t w e e n t h e c l i e n t s a n d t h e c o n t r o l s

o n th e s e l f - r e p o r t m e a s u r e s o f a n x i e t y a n d d e p r e s s i o n w e r e e x a m i n e d u s i n g t

t e s t s . I n b o t h e x p e r i m e n t s t h e c l i e n t s s c o r e d h i g h e r t h a n t h e c o n t r o l s o n a l l

m e a s u r e s ( al l p s < 0 . 0 0 0 0 1 ) . I n a d d i t io n , t h e t w o c l i e n t g r o u p s a n d t h e tw o

c o n t r o l g r o u p s d i d n o t d i f f e r s i g n if i ca n t ly o n a n y m e a s u r e s a f t e r c o n t r o l o f

T y p e I e r r o r r a t e s .

P l a n n e d t t e s t s w e r e c o n d u c t e d , b a s e d o n t h e p r e d i c t i o n s s t a t e d in th e i n t r o -

d u c t io n : m e a n n u m b e r s o f r e c a l le d w o r d s ( o u t o f 1 0 t h r e a t a n d 1 0 n o n t h r e a t

w o r d s ) a r e r e p o r t e d in T a b l e 3 . I n a d d i t i o n , e f f e c t s iz e s ( p o i n t - b i s e r i a l c o r r e l a -

t io n s ) a r e r e p o r t e d . A m o d i f i e d B o n f e r r o n i p r o c e d u r e ( S i m e s , 1 9 86 ) w a s u s e d

t o c o n t r o l h y p o t h e s i s - w i s e T y p e I e r r o r r a t e s . I n b o t h e x p e r i m e n t s , t h e G A D

g r o u p r e c a l le d s i g n i f ic a n t ly m o r e t h r e a t w o r d s t h a n n o n t h r e a t w o r d s [ E x p e r i -

m e n t 1: t ( 6 2 ) = 6 . 2 9 , p < . 0 0 1 , rp b = 0 . 6 2 ; E x p e r i m e n t 2 : t ( 5 1 ) = 3 . 6 9 , p <

.004 , one - t a i l ed , / ' i 0b = 0 . 4 6 ] . F u r t h e r m o r e , t h e G A D g r o u p r e c a l l e d s i g n i f i -

c a n t l y m o r e t h r e a t w o r d s t h a n t h e c o n t r o l g r o u p d i d i n b o t h s t u d i e s [ E x p e r i -

m e n t 1: t ( 6 2 ) = 3 .6 9 ,p < . 0 0 1 , r pb ---- 0 . 4 2 ; E x p e r i m e n t 2 : t (5 1 ) = 2 . 0 0 , p <

. 0 3 , o n e - t a i l e d , rpb ---- 0 . 2 7 ] . T h e r e w a s a m a r g i n a l l y s i g n i f i c a n t t r e n d i n t h ec o n t r o l g r o u p in E x p e r i m e n t 1 f o r r e c a ll o f m o r e t h r e a t t h a n n o n t h r e a t w o r d s ,

t ( 6 2 ) = 1 .4 6 , p < . 0 8 , o n e - t a i l e d , rp b ---- 0 .1 8 , t h a t r e a c h e d s i g n i f i c a n c e i n

E x p e r i m e n t 2 , t ( 5 1 ) = 1 . 9 1 ,p < . 0 3 , o n e - t a i l e d , rp b ---- 0 .2 6 , b u t d i d n o t su r -



M E M O R Y B IA S I N G E N E R A L I Z E D A N X I E T Y D I S O R D E R 7 5 1

T A B L E 3

M E A N S A N D S T A N D A RD D E V IA T I O N S F OR N U M BE R O F T H RE A T A N D

N O N T H RE A T W O RD S RE CA L L E D

W o r d T y p e

G r o u p T h r e a t N o n t h r e a t


G A D 4 . 6 ( 1 .5 ) 3 . 0 ( 1 .7 )

C o n t r o l 3 . 3 ( 1 . 3 ) 2 . 9 ( 1 . 2 )


G A D 4 . 7 ( 1 .7 ) 3 . 5 ( 1 .7 )

C o n t r o l 3 . 7 ( 1 . 8 ) 3 . 0 ( 1 . 3 )

v i v e e r r o r c o r r e c t i o n . H o w e v e r , t h e e f f e c t s i ze s i n d i c a t e d t h a t t h e e f f e c t w a s

n o n t r iv i a l. T h e d i f f e r e n c e b e t w e e n G A D a n d c o n t r o l g r o u p s f o r r ec a l l o f n o n -

t h r ea t w o r d s d i d n o t a p p r o a c h s i g n if i ca n c e in e i t h e r e x p e r i m e n t ( E x p e r i m e n t

1: rpb = 0 . 0 2 ; E x p e r i m e n t 2 : rp b = 0 . 1 6 ) . T o e x a m i n e p o s s i b l e d i f f e re n t i a l

r e c a l l o f so c i a l t h r e a t v e r s u s p h y s i c a l t h r e a t w o r d s , a n a l y s i s o f v a r i a n c e u s i n g

g r o u p ( G A D v s . C o n t r o l ) a s a b e t w e e n - s u b j e c t s f a c t o r a n d w o r d t y p e ( s o c ia l

v s . p h y s i c a l th r e a t ) a s a w i t h i n - s u b j e c t s f a c t o r w a s c o n d u c t e d f o r e a c h e x p e r -

i m e n t . T h e r e w e r e n o s i g n i f i c a n t i n t e r a c t i o n s b e t w e e n g r o u p a n d w o r d t y p e

[ E x p e r i m e n t l : F ( 1 , 6 2 ) = 0 . 0 6 6 , p = 0 . 7 9 ; E x p e r i m e n t 2: F ( 1 , 5 1 ) =

2 . 3 5 , p -- 0 . 13 ] .

Discuss ion

A n e x p l i c it m e m o r y b i a s f o r th r e a t w o r d s w a s r e p l i c a t e d ac r o s s t w o s e p a -

r a te G A D s a m p l e s u n d e r c o n d i t io n s r e c o m m e n d e d a s i d ea l fo r d e t e c t i o n o f

m e m o r y b i a s e s i n s tu d i e s o f a n x i e ty : n a m e l y , i n c i d e n t a l l e a r n i n g a n d f r e e

r e c a l l ( B e c k e r e t a l ., 1 9 9 9 ) . I n d e e d , t h e o v e r a l l t o t al n u m b e r o f c o r r e c t l y

r e c a l l e d w o r d s w a s i n a c c o r d w i t h t h is r e s e a r c h . H o w e v e r , t h e p r e s e n t d a t a

c o n f l i c t w i t h a b o d y o f l it e r a tu r e t h a t h a s f a i l e d to f i n d a n e x p l i c i t m e m o r y

b i as i n G A D ( B e c k e r e t al .; B r a d l ey , M o g g , & W i l li a m s , 1 9 9 5; M a c L e o d &

M c L a u g h l i n , 1 9 95 ; M a t h e w s , M o g g , M a y , & E y s e n c k , 1 9 8 9) , t h o u g h e x c e p -

t i o n s t o t h i s t r e n d c a n b e f o u n d ( M o g g & M a t h e w s , 1 9 9 0 ; O t t o , M c N a l l y ,

P o l l a c k , C h e n , & R o s e n b a u m , 1 9 9 4 ). M o g g e t al . a t tr ib u t e d th e i r f in d i n g t o a

r e s p o n s e b i a s i n G A D t o w a r d m o o d - c o n g r u e n t w o r d s , r a t h e r t h a n a s e l e c t i v e

m e m o r y e f f ec t . H o w e v e r , p a r ti c ip a n t s i n t h is s t u d y w e r e a w a r e t h a t t h e y

w o u l d r e c e i v e a r e c a l l t e s t , a n d s o t h e t a s k d o e s n o t q u a l i f y a s i n c i d e n t a l

l e a r n i n g . T h i s d i f f e r e n c e r e n d e r s t h e f i n d i n g s l e s s d i r e c t l y c o m p a r a b l e t o

e i t h e r B e c k e t e t a l. o r t h e p r e s e n t s t u dy . O t t o e t a l. f o u n d a n e x p l i c i t m e m o r yb i as o n l y i n l e f t - h e m i s p h e r e - d o m i n a n t G A D s u b j ec t s; t h is e f f e c t i s co n s i d -

e r e d i n g r e a t e r d e t a i l b e l o w .

T h e h y p o t h e s i z e d m e m o r y b i a s f o r th r e a t i n th e c o n t r o l g r o u p w a s l es s



752 FRIED MAN ET AL.

r o b u s t l y s u p p o r t e d , a s e v i d e n c e d b y s m a l l e r e f f e c t s i z es a n d t h e m a r g i n a l s i g -

n i f i c a n c e o f t h e e f f e c t . O n e l i k e l y e x p l a n a t i o n f o r t h i s d i f f e r e n c e i s t h a t t h e

t h r e a t w o r d s w e r e l e s s a r o u s i n g a n d s i g n i f i c a n t f o r t h e c o n t r o l g r o u p . T h i s

p o s s i b i l i t y i s s u p p o r t e d b y t h e c l e a r b i a s f o r t h e t h r e a t w o r d s b y t h e G A Dp a t ie n t s i n b o t h s t u d ie s w h e n c o m p a r e d t o t h e c o n t r o l g ro u p s . M o r e o v e r , as

p r e d i c t e d , t h e r e w e r e n o g r o u p d i f f e r e n c e s i n r e c a l l f o r n o n t h r e a t w o r d s ,

w h i c h f u r t h e r s u p p o rt s t h e s a l ie n c e o f th e t h r ea t w o r d s t o t h e G A D g r o u p .

I n g e n e r a l , th e p r e s e n t r e s u lt s h i g h l i g h t th e p o i n t s e m p h a s i z e d b y B e c k e r e t

a l . ( 1 9 9 9 ; i .e ., m e t h o d o l o g i c a l i n c o n s i s t e n c i e s a n d t h e r o l e o f p h y s i o l o g i c a l

a r o u s a l i n a n x i e t y ) i n t h e i r a t t e m p t t o a c c o u n t f o r i n c o n s i s t e n t m e m o r y b i a s

f i n d i n g s a c r o s s a n x i e t y s t u d i e s . O n e m e t h o d o l o g i c a l v a r i a n c e t h a t m a y

a c c o u n t f o r d i f f e r e n c e s i n f in d i n g s i n v o l v e s t h e n a t u r e o f t h e ta s k s . M a n y

s t u d ie s o f m e m o r y b i a s i n G A D h a v e u s e d v e r y b r i e f st im u l u s e x p o s u r e

t i m e s , t o w h i c h a n a c t i v e r e s p o n s e i s r e q u i r e d ( B o r k o v e c e t a i. , 1 9 9 8 ) . In c o n -

t r a st , t h e p r o t r a c t e d , p a s s i v e v i e w i n g o f t h e S 1 - $ 2 t a s k in t h e p r e s e n t s t u d y

m a y h a v e o v e r r i d d e n t h e a v o i d a n t a s p e c ts o f w o r r y , a n d s o r e s u l t e d i n

e n h a n c e d r e t e n ti o n o f t h r e at w o r d s .

A n o t h e r d i s t i n c ti o n c a n b e m a d e r e g a r d i n g t h e n a t u re o f t h e s ti m u l i . A

c o m m o n l y u s e d p r o c e d u r e i n v o l v e s t h e g e n e r a ti o n o f s e lf - r e fe r e n t i m a g e s t o

t h r e a t a n d n o n t h r e a t w o r d s ( e . g . , B e c k e r e t a l. , 1 9 9 9 ; M a t h e w s e t a l. , 1 9 8 9 ) .

I n c o n t r a s t , i n s t r u c t i o n s i n t h e p r e s e n t t a s k w e r e t o s i m p l y r e a d t h e w o r d s

s i le n t ly . I t is p o s s i b l e t h a t t h e p r o c e s s o f i m a g i n i n g o n e s e l f i n a n a n x i e t y -

p r o v o k i n g s c e n a r i o e li c i ts g r e a t e r c o g n i t i v e a v o i d a n c e a n d t h e r e f o r e le s s s t ra -t e g i c e l a b o r a t i o n t h a n m e r e l y r e a d i n g a t h r e a t e n i n g w o r d . T h e l a t t e r t a s k m a y

i n f a c t b e b e t t e r m a t c h e d t o t h e c h a r a c t e r i s t i c t e n d e n c y t o w a r d w o r r y a n d

r u m i n a t i o n in G A D , w h i c h i s m a r k e d b y t h e d o m i n a n c e o f v e r b a l- l in g u i s t ic

p r o c e s s i n g o v e r i m a g e r y ( B o r k o v e c & I n z , 1 9 90 ; B o r k o v e c e t a l. , 1 9 9 8;

L y o n f i e l d s , B o r k o v e c , & T h a y e r , 1 9 9 5 ). F u r t h e r m o r e , th e u s e o f i m a g e r y i n

g e n e r a l m a y y i e l d n o p a r t i c u l a r a d v a n t a g e i n t e r m s o f a c q u i s i t i o n a n d r e t e n -

t i o n ( P o s t m a n , 1 9 7 4 ) . In s u m , t h e S 1 - $ 2 t a sk u s e d i n t h e p r e s e n t s tu d y m a y

b e s i n g u l a rl y c o n g r u e n t w i t h G A D in te r m s o f d e t e c ti n g a n e x p l ic i t m e m o r y

b i a s . O n t h e o t h e r h a n d , a l t h o u g h i m a g e r y t a s k s m a y b e c o n c e p t u a l l y c o m -

p a t ib l e w i t h f r e e r ec a l l ( B e c k e r e t al .) , t h e y m a y n o t b e w e l l m a t c h e d t o G A D .

I n d e e d , t he l o w c a p a c i t y f o r g e n e r a t i o n o f f e a r i m a g e r y i n G A D h a s b e e n

i n v o k e d t o e x p l a in t h e r a p y o u t c o m e d i f fe r e n c e s b e t w e e n G A D a n d o t h e r a n x -

i e t y d i s o r d e r s s u c h a s s p e c i f i c p h o b i a s , i n w h i c h v i v i d f e a r i m a g e s a r e m o r e

r e a d i l y p r o d u c e d ( L a n g , L e v i n , M i l l e r , & K o z a k , 1 9 8 3 ) . T h e f a c t t h a t t h e

e f f e c t s iz e s r e p o r t e d h e r e a r e t w o t o t h r e e t im e s g r e a t e r t h a n t h o s e r e p o r t e d i n

B e c k e r e t a l . l e n d s f u r t h e r s u p p o r t t o th e s e n o t i o n s .

T h i s r e a s o n i n g is c o n s i s t e n t w i t h t h e fi n d i n g o f a n e x p l i c i t m e m o r y b i a s i n

G A D i n d i v i d u a l s w h o d i s p l a y a l e f t - h e m i s p h e r i c b ia s ( O t t o e t a l ., 1 9 9 4 ) . T h e

l e f t c e r e b r a l h e m i s p h e r e is g e n e r a ll y d o m i n a n t f o r l an g u a g e a n d v e r b a l m e m -o r y , a n d t h e r ig h t h e m i s p h e r e f o r i m a g e r y a n d n o n v e r b a l m e m o r y ( B r a d s h a w ,

1 9 8 9 ; B r y d e n & L e y , 1 98 3 ; K o l b & W h i s h a w , 1 9 9 0 ). H e n c e , a m e m o r y b i as

i n v o l v i n g v e r b a l m a t e r i a l i s m o r e l i k e l y t o a p p e a r i n l e f t - d o m i n a n t i n d i v i d u -



MEMORY BIAS IN G ENE RAL IZE D ANXIETY DISORDER 753

a l s . I n f a c t , t h e c h a r a c t e r i s t i c w o r r y o f G A D i s m a r k e d b y l e f t f r o n t a l h e m i -

spher ic ac t i va t ion (B orkovec e t a l ., 1998). T hus , bo th t he cen t ra l ne rvous sys t em

and i n fo rmat ion p roces s ing cha rac t e r i s t i c s o f GAD under sco re t he po t en t i a l

i n a p p r o p r i a t e n e s s o f i m a g e r y t a s k s f o r t h e d e t e c t i o n o f m e m o r y b i a s e s i n th i sd i so rde r .

P h y s i o l o g i c a l a r o u s a l h a s b e e n i n v o k e d l o o s e l y i n c a u s a l s p e c u l a t io n s o f

m e m o r y d i f f e re n c e s b e t w e e n p a n i c a n d G A D ( B e c k e r e t a l. , 1 9 9 9) . H o w e v e r ,

a m o d e l t h a t c a n m o r e s p e c i f ic a l l y r e l a te i n f o r m a t i o n p r o c e s s i n g t o p h y s i o -

l o g ic a l r e s p o n d i n g m a y b e m o r e u s e f u l th a n g l o b a l , n o n s p e c i fi c d e p ic t io n s o f

p h y s i o l o g i c a l a r o u s a l . T h e f o r m e r a p p r o a c h w a s t a k e n i n o u r i n v e s t i g a t i o n

( f r o m w h i c h t h e p r e s e n t d a t a w e r e o b t a i n e d ) o f p h a s i c h e a r t r at e ( H R )

r e s p o n s e s t o r e p e a t e d p r e s e n t a t io n o f t h r e a t w o r d s i n G A D ( T h a y e r e t a l ., i n

p r e s s) . In t h a t r e p o r t , t h e G A D g r o u p d e v e l o p e d a c o n d i t i o n e d H R d e c e l e r a -

t i o n i n a n t i c i p a t i o n o f t h r e a t w o r d s , a p h y s i o l o g i c a l c h a n g e t h a t s u g g e s t s

f a c i l it a t io n o f s ti m u l u s i n t a k e ( B o h l i n & K j e l b e r g , 1 9 7 9 ). F u r t h e r m o r e , t h e s e

i n d i v i d u a l s a l s o e x h i b i te d a H R a c c e l e r a t i o n i n r e s p o n s e t o t h e th r e a t w o r d s ,

w h i c h , i n a c c o r d w i t h m o d e l s t h a t l i n k i n c r e a s e d a d r e n e r g i c a c t i v i t y w i t h

e n h a n c e d m e m o r y , m i g h t ha v e i m p r o v e d s ti m u lu s r e te n ti o n ( M c G a u g h ,

1 9 9 2 ). T h e a d a p t i v e v a l u e o f th i s m e c h a n i s m p r e s u m a b l y e n t a i l s th e s e l e c t iv e

r e c a l l o f s a l i e n t e m o t i o n a l e v e n t s , s u c h a s a t h r e a t e n i n g e n c o u n t e r . I n G A D ,

d e f e n s i v e c o g n i t i v e o p e r a t i o n s o c c u r a t m u l t i p l e s t a g e s o f i n f o r m a t i o n p r o -

c e s s in g : T h e r e i s a p r e -a t t e n ti v e b i a s t o w a r d d e t e c t i o n o f th r e a t e n i n g s t im u l i

a n d e x c e s s i v e r u m i n a t i o n o f s t o r ed t h r e a t i n f o rm a t i o n . T h is c o m b i n a t i o n m a ya c c o u n t f o r t he c o n v e r g e n t f in d i n g s o f a n i m p l i c it m e m o r y b i a s in G A D ( se e

B ecker e t a l . , 1999 ; Wi l l i ams e t a l . , 1997 , fo r r ev i ews ) , a s we l l a s pos i t i ve

f in d i n g s o f a n e x p l i c it m e m o r y b i a s i n G A D u n d e r c e r t a in c o n d i ti o n s .

I t h a s a l s o b e e n s u g g e s t e d t h a t t h e p r o c e s s i n g o f e m o t i o n a l s t i m u l i is p r i-

m a r i l y m o d e r a t e d b y p r e - i n t e n t i o n a l , a u t o m a t i c m e c h a n i s m s ( L i b k u m a n ,

N i c h o l s - W h i t e h e a d , G r i f f i th , & T h o m a s , 1 9 9 9 ). S t i m u l u s o r i e n t i n g , w i t h

a c c o m p a n y i n g H R d e c e l e r a ti o n , o c c u r s a t t h is e a r l y s t a g e o f i n f o r m a t i o n pr o -

c e s s i n g . T h i s r e s p o n s e i s in d i c a t i v e o f e n h a n c e d a t t e n t io n t o e x t e r n a l s t i m u l i ,

w h i c h m a y i n tu r n e l i c it g r e a t e r in t a k e o f p e r i p h e r a l c u e s , a n o t i o n t h a t i s c o n -

s i s t e n t w i t h t h e h y p e r v i g i l a n c e a n d c h a r a c t e r i s t i c s c a n n i n g o f t h e e n v i r o n -

m e n t f o r th r e a t c u e s t h a t i s a s s o c ia t e d w i t h a n x i e t y ( M a t h e w s , 1 9 9 0) . V i e w e d

a s s u c h , t h e e n h a n c e d r e t e n t i o n o f t h r e a t i n f o r m a t i o n in a n x i e t y is e s s e n t i a l l y

a n e n c o d i n g , r a t h e r t h a n r e h e a r s a l o r e l a b o r a t i o n , p h e n o m e n o n ( L i b k u m a n e t

a l .) . The H R acce l e ra t i on i n response t o th rea t words , obse rved i n G A D sub j ec ts

i n Th aye r e t a l . ( in p res s ) , l i ke ly r e f lec t s a de fens ive r e sponse , r a t he r t han cogn i -

t ive e l abo ra t i on , t ha t fu r t he r improv es r e t en t i on v i a e m ot iona l a rousa l .

I n s u m , a l t h o u g h t h e d a t a o n e x p l i c i t r e c a l l b ia s e s i n a n x i e t y r e m a i n " d i f f i-

c u l t to c h a r a c t e r i s e " ( W i l li a m s e t a l ., 1 9 9 7, p . 2 8 6 ) , i t s e e m s p r e m a t u r e a t th i s

j u n c t u r e t o d i s m i s s o u t o f h a n d s u c h a b i a s . R a t h e r , s u c h t e n d e n c i e s c a n b eo b s e r v e d i n c e r t a i n s i tu a t i o n s ( e .g . , e x t e n d e d s t i m u l u s e x p o s u r e t i m e s ) a n d i n

i n d i v i d u a l s w i t h p a r t i c u l a r d i s t i n g u i s h i n g f e a t u r e s ( e . g . , l e f t - h e m i s p h e r e

d o m i n a n c e ) . T h e p a r a m e t e r s o f t h e s e t e n d e n c i e s s h o u l d b e p u r s u e d f u r t h e r



75 4 FRIED MA N ET A L.

through employment of var ious types and combinat ions of l earning and

m emo ry tasks rather than with f ixed procedures that may yie ld cons is tency

across s tudies but occ lude a com prehens ive depic t ion of G A D . I t a l so may b e

rash to chal lenge broadly influential cognitive models of memory in anxiety(e .g . , Beck , Em ery, & Greenberg, 198 5; Bow er , 1981 ; W ill iams e t a l . ; c f .

Be cke r et al. , 1999, p. 16 2) based on a narrowly defined m emory methodology.

Ad dit ional ly , the concurrent assessment of phys io log ical data wi th spec i f ic

theoretical l inks to information processing, such as phasic cardiac responding

(e.g. , Thayer et al. , 2000) or HR variability (Friedman & Thayer, 1998; Lyon-

fie lds et al . , 1995; Thayer et al . , 1996) may a l low fo r the precise mapping of

somatic activity to cognitive phenomena. This approach is l ikely to be more

fruit fu l t ha n inc lus ion o f nonsp ec i f ic , g lobal measures of ph ys io logical

arousal , a dated paradigm that has been cons istently refuted in psy cho ph ysio-

logical research (Lacey, 1967; Venables, 1984; Wolf, 1995). Ultimately,

methodological diversity coupled with an appreciation of the psychophysio-

log ic a l c om p le x i t ie s o f G AD wi l l h e lp advan ce c ogn i t ive m o d e l s th at c an

account for a wide range of information processing phenomena in this and

other anxiety disorders.

References

A m e r i c a n P s y c h i a t ri c A s s o c i a ti o n . ( 1 9 8 7 ) . Diagnostic and statistical ma nua l of me ntal disor-

ders (3 rd ed . , rev .) . W ash ing ton , D C: A u tho r .

Beck , A . T. , Emery , G . , & G r eenb e rg , R . L . (11985 ). Anxie ty d isorders and phobias . N ew Y ork:

B a s i c B o o k s .

Beck , A . T . , W ard , C .H . , Mende l son , M. , Mock , J . , & Er lbaugh , J . (1961 ) . A n inven to ry fo r

m e a s u r i n g d e p r e s s io n . Archives o f Genera l Psychiatcv . 4 , 5 3 - 6 1 .

Becke r , E . S . , Ro th , W . T ., A n dr i ch , M. , & M arg ra f , J . (1999 ) . Exp l i c i t mem ory b i a s i n anx i e ty

d i so rde rs . Journal o f Ab norm al Psychology, 108, 1 5 3 - 1 6 3 .

Boh l in , G . , & K je lbe rg , A . (1979 ) . O r i en t i ng ac t i v i t y i n tw o-s t imu lus pa rad igm s a s re f l ec t ed in

hea r t ra t e . In H .D . K imm el , E .H . van O l s t , & J . F . O r l ebek e (Eds . ) , The orienting reflex in

humans (pp . 1 6 9 - 1 9 7 ) . H i t l sd a l e , N J : L a w r e n c e E r l b a u m A s s o c i a te s .

Bo rkovec , T . D . , & Inz , J . (1990 ) . The na tu re o f w orry i n gene ra l i zed anx i e ty d i so rde r : A p re -

d o m i n a n c e o f t h o u g h t act iv i ty . Behavior Research and Therapy. 28 , 1 5 3 - 1 5 8 .

Borkovec , T . D . , Ray , W . J . , & S tobe r , J . (1998 ) . W orry : A cogn i t i ve phenomenon in t ima te ly

l i nked t o a f fec t i ve , phys io log i ca l , and i n t e rpe rsona l behav io ra l p rocesses . Cognitive Ther-

a p y and Research, 6, 5 6 1 - 5 7 6 .

B o w e r , G . H . ( 1 9 8 1 ) . M o o d a n d m e m o r y . Am erican Psychologis t, 36 , 1 2 9 - 1 4 8 .

Brad l ey , B . P . , Mogg , K . , & W i l l i ams , R . (1995 ) . Imp l i c i t and exp l i c i t memory b i a s fo r emo-

t i on -cong ruen t i n fo rma t ion i n c l i n i ca l dep ress ion and anx i e ty . Behav iour Research and

Therapy , 33 ,755-770 .

Bradshaw , J . L . (1989 ) . He mis phe ric specialization and psyc holo gica l ¢imction. N ew Y ork :

W i l ey .

B r o w n , T . A . , A n t o n y , M . M . , & B a r l o w , D . H . ( 1 9 9 2 ) . P s y c h o m e t r i c p r o p e r t i e s o f t h e P e n n

Sta t e W orry Q ues t i onna i re i n a c l i n i ca l anx i e ty d i so rde rs samp le . Behaviour Research and

Therapy, 30, 3 3 - 3 8 .

Bryde n , M. R , & Ley, R . G . (1983 ) . R igh t hemisp he re i nv o lvem en t i n image ry and a f fec t , i n E .

P e r e c m a n ( E d . ) , Cognitive processing in the right hemL~phere (pp . 1 11 -12 3 ) . N ew Y ork :

A c a d e m i c P r e s s .



M E M O R Y B IA S I N G E N E R A L I Z E D A N X IE T Y D I SO R D E R 7 5 5

C l o i t re , M . , & L e i b o w i t z , M . R . ( 1 9 9 1 ) . M e m o r y b i a s i n p a n i c d i s or d e r : A n i n v e s t ig a t i o n o f t h e

c o g n i t iv e a v o i d a n c e h y p o t h e s i s . Cognitive Therapy and Research, 15, 3 7 1 - 3 8 6 .

DiN ardo , P. A. , & B arlow, D. H. (1988). At trie ~ Disorders bzterviews Schedule-Revised (ADIS-R).

A l b a n y : S t a t e U n i v e r s i ty o f N e w Y o r k a t A l b a n y .

E y s e n c k , M . W . , & B y r n e , A . ( 1 9 9 4 ). I m p l i c it m e m o r y , e x p l ic i t m e m o r y b i a s , a n d a n x i e t y . Cog-ni t ion and Emotion , 8 , 4 1 5 - 4 3 1 .

Fr i ed m an , B . H . , & Thay e r , J . F . (1998 ) . A nx ie ty and a u tono mic f l ex ib i l it y : A ca rd iovasc u l a r

a p p r o a c h . Biological Psychology, 49 ,30 3-3 23 .

G r a f , P ., ( 19 9 4 ) . E x p l i c it a n d i m p l i c i t m e m o r y : A d e c a d e o f r e s e a r c h . I n C . U m i l t a & M . M o s -

c o v i t c h ( E d s . ) , Attent ion and perform ance, Vol . XV : Conscious and no nconscious in forma-

tion processing ( p p . 6 8 1 - 6 9 6 ) . C a m b r i d g e , M A : B r a d f o r d .

H a m i l t o n , M . ( 1 9 5 9 ) . T h e m e a s u r e m e n t o f a n x i et y s t a te s b y r a t in g . Br i t ish Journa l o f Med ica l

Psychology, 32, 5 0 - 5 5 .

H a m i l t o n , M . ( 1 9 6 0 ) . A r a t i n g s c a l e f o r d e p r es s i o n . Jour nal of Neurology, Neurosurgery, and

Psychiatry, 23, 5 6 - 6 2 .

H e ide , F . J . , & B orkovec , T . D . (1983 ) . Re l axa t i on - induc ed anx i e ty : Pa radox ica l anx i e ty enhanc e -

me n t due t o re l axa t i on t ra in ing . Journal o f Consulting and Clinical Psychology, 51, 1 7 1 - 1 8 2 .

K o lb , B . , & W hi shaw , I . Q . (1990 ) . Fund ame ntals o f hum an neuropsychology (3 rd ed . ) . N ew

Y ork : Freeman .

Lacey , J . I . (1967 ) . So ma t i c re sponse pa t t e rn ing and s t re s s : Som e rev i s ions o f ac t i va t i on t heo ry .

I n M . H . A p p l e y & R . T r u m b u l l ( E d s .) , Psychological stress: Issues in research ( p p . 1 4 -

4 2 ) . N e w Y o rk : A p p l e t o n - C e n t u r y - C r o f t s .

Lan g , P . J . , Lev in , D . N . , M i l l e r , G . A . , & K ozak , M . J . (1983 ) . Fea r be hav io r , fea r image ry , and

t h e p s y c h o p h y s i o l o g y o f e m o t i o n : T h e p r o b l e m o f a f f e c t iv e r e s p o n s e i n t e g r a ti o n . Journa l

o f Abno rmal Psychology . 92 ,2 76- 306 .

L i b k u m a n , T . M . , N i c h o l s - W h i t e h e a d , P ., G r i ff i th , J . , & T h o m a s , R . ( 1 9 9 9 ) . S o u r c e s o f a r o u s a l

a n d m e m o r y f o r d e t a il . M em ory & Cognition . 2 7 , 1 6 6 - 1 9 0 .

Lyonf i e ld s , J . D . , Bo rkovec , T . D . , & Th aye r , J . F . (1995 ) . V agal t on e i n gene ra l i zed anx i e ty d i s -

o r d e r a n d t h e e f f e c t s o f a v e rs i v e im a g e r y a n d w o r r i s o m e t h i n k i n g . Behavior Therapy. 26 ,

4 5 7 - 4 6 6 .

M a c L e o d , C . , & M c L a u g h l i n , K . ( 1 9 9 5 ) . I m p l i c i t a n d e x p l i c it m e m o r y b i a s in a n x i e ty : A c o n -

cep tua l rep l i ca t i on . Behaviour Research and Therapy. 33 , 1 - 1 4 .

M a t h e w s , A . ( 1 9 9 0 ) . W h y w o r r y ? T h e c o g n i t iv e f u n c t i o n o f a n x i e ty . Behav iour Research and

Therapy , 28 ,455-468 .

M a t h e w s , A . , & M a c L e o d , C . ( 1 9 8 6 ) . S e l e c t i v e p r o c e s s i n g o f t h r e a t i n a n x i e ty s t at e s. Journa l o f

Abnorm al Psychology , 95 ,563 -569 .

M a t h e w s , A . , M o g g , K . , M a y , J . , & E y s e n c k , M . ( 1 9 8 9 ) . I m p l i c i t a n d e x p l i c it m e m o r y b i a s i n

anx i e ty . Journa l o f Abnorm al Psychology , 98 ,2 36- 240 .

M c G a u g h , J . L . ( 1 99 2 ) . A f f e c t , n e u r o m o d u l a t o r y s y s t e m s , a n d m e m o r y s t o ra g e . I n S .- A . C h r i s -

t i an son (Ed . ) , Handbo ok o f emo tion and mem ory : Research and theory. ( p p . 2 4 5 - 2 6 8 ) .

H i l l s d a le , N J : E r l b a u m .

M eyer , T . J . , Mi l l e r , M . L . , Me tzge r , R . L . , & Bork ovec , T . D . (1990 ] . D eve lop me n t and va l i da -

t i on o f t he Penn S t a t e W orry Q ues t i onna i re . Behaviour Research and Therapy, 28, 4 8 7 - 4 9 5 .

M o g g , K . , & M a t h e w s , A . ( 1 9 9 0 ) . I s t h e re a s e l f - r e f e r e n t m o o d - c o n g r u e n t r e c a ll b i a s i n a n x i-

e ty? Behaviour Research and Therapy, 28 , 9 1 - 9 2 .

M o g g , K . , M a t h e w s , A . , & W e i n m a n , J . ( 1 9 8 9 ). S e l e c t i v e p r o c e s s i n g o f t h r e a t c u e s i n a n x i e t y

s t a t es : A conce p tua l rep l i ca t i on . Behaviour Research and Therapy, 27 , 3 1 7 - 3 2 3 .

O t t o , M . W . , M c N a l l y , R . J . , P o ll a c k , M . H . , C h e n , E . , & R o s e n b a u m , J . F . (1 9 9 4 ) . H e m i s p h e r i c

l a t e ra l i ty and me m ory b i a s fo r t h rea t i n anx i e ty d i so rde r . Journal o f Ab norm al P sychology,1 0 3 , 8 2 8 - 8 3 1 .

P o s t m a n , L . ( 1 9 7 4 ) . D o e s i m a g e r y e n h a n c e l o n g - t e r m r e t e n t i o n ? Bulle t in o f the Psy chon om ic

S o c ie ~ , 3 , 3 8 5 - 3 8 7 .



756 FRIEDMAN ET AL.

Simes, R. J. (1986). An improved Bonferroni procedure for multiple tests of significance.

Biometr ika , 73 , 751-754.

Spielberger, C. D., Gorsuch, R. L., Lushene, R., Vagg, P. R., & Jacobs, G. A. (1983). M a n u a l

jo r the State-Trait An.rietv lm,entorv. Palo Alto, CA: Consulting Psychologists Press.

Squire, L.R. (1992). Memory and the hippocampus: A synthesis from findings with rats, mon-

keys, and humans. Psychological Review, 99 , 195-231.

Thayer, J. F., Friedman, B. H., & Borkovec, T. D. (1996). Autonomic characteristics of general-

ized anxiety disorder and worry. Biological Psychiatry . 39 ,255 266.

Thayer, J. F., Friedman, B. H., Borkovec, T. D., (2000). Ph ysiolog ical and attentional charac-

teristics (,?fgeneralized an xiet y disorder: A replicruion. Unpublished raw data.

Thayer, J. F., Friedman, B. H., Borkovec, T. D., Johnsen, B. H., & Molina, S. (2000). Phasic

heart period reactions to cued threat and non-threat stimuli in generalized anxiety disorder.

Psychophysiology, 37, 361 368.

Venables, R H. (1984). Arousal: An examination of its status as a concept . In M.G.H. Coles,

J.R. Jennings, & J.P. Stern (Eds.), Psychophysio logical perspect ives (pp. 134-142). New

York: Van Nostrand.

Williams, J. M. G., Watts, F. N., MacLeod, C., & Mathews, A. (1997). Cognitive p©,chology

and e motiona l d isorders (2nd ed.). Chichester, England: Wiley.

Wolf, S. (1995). Dogmas that have hindered understanding, hltegrative Ph ysiolo gica l an d

Behavioral Science, 30, 3~4.

RECEIVED: January 3, 2000

ACCEPTED: May 1,2000

explicit memory bias

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