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Running head: LINEUP TYPE AND CORRECT REJECTIONS

Correct Rejections in Sequential and Simultaneous Lineups

Sean Weigold Ferguson

Rollins College

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Abstract

This experiment tested the difference in correct rejections of suspects by witnesses after a mock

crime in sequential and simultaneous lineups. Study participants were 20 students from a small

liberal arts college. Participants viewing a sequential lineup made more correct rejections than

participants viewing a simultaneous lineup.

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Seventy years of research have shown us the great plasticity of memory, in contrast to the

popularized notion of its reliability (Sharps, Hess, Casner, Ranes, & Jones, 2007). This

phenomenon is particularly important in situations in which great consequences hinge upon the

accuracy of an individual's memory, e.g., eyewitness testimony. In fact, thousands of staged-

crime experiments have shown that false identifications in lineup scenarios are quite common

(Wells, 1993).

The two most commonly used types of lineups are sequential and simultaneous. A

witness views suspects one at a time in a sequential lineup, whereas a witness views a group of

suspects at the same time in a simultaneous lineup. Of the research comparing these two

methods, most has shown that the type of lineup used has no effect on correct suspect

identification (Kneller, Memon, & Stevenage, 2001), but when the guilty suspect is absent from

the lineup, sequential lineups have been shown to decrease incidences of incorrect identifications

(Steblay, Dysart, Fulero, & Lindsay, 2001). However, new research contradicts this finding, and

indicates that there are many factors that mediate the effectiveness the two lineup methods

(Carlson, Gronlund, & Clark, 2008). One such factor may be the presence of non-suspect

distracters during the lineup (Jenkins, Lavie, & Driver, 2005).

However, the purpose of the present study is to explore the differences in correct

rejections between sequential and simultaneous lineups without considering incorrect rejections

or suspect identifications. We predict that participants viewing a sequential lineup will make

more correct rejections than participants viewing a simultaneous lineup.

Methods

Participants

Twenty college students from a psychology course at a small, 4-year liberal arts

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secondary education institution volunteered to participate in this experiment. Of this group, 15

were female, 1 was male, and 4 declined to report their gender. Participants' ages ranged from 19

to 36 with a median age of 21 years. Their class year ranged from 2010 (senior) to 2013

(freshman) with a mean year of 2011 (SD = 1.0 years). Four students did not report their year or

class age, and their data was replaced with the mean of each variable.

Materials

We created a short video portraying a scene from a female college student's birthday

party. Confederates played the characters in the video. Towards the end of the scene, one of the

characters picked up the party's birthday cake, and exited the room. This portion of the video was

filmed with the intention of ensuring the “theft” would not be obvious to viewers. We then shot

individual portrait photographs of each confederate as seen in Figure 1. Participants were given

informed consent forms, and response sheets.

Figure 1. Individual portrait photographs used in lineups.

Measures

Participants were asked to report their demographics and indicate which confederates

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(suspects) they believed did not steal the cake on their response sheets. Participants were

instructed to eliminate a suspect by crossing that suspect's number off on the response sheet. For

each suspect elimination, participants were instructed to also indicate how certain they were of

the elimination being correct by circling “not at all,” “somewhat,” or “very.”

Procedure

The experiment took place during the participants' class. We gave out informed consent

forms to the students, and asked them to read, sign, and return them. After they had all returned

the forms, participants viewed the “cake theft” video together. Prior to the experiment, we

labeled each response sheet with the letter “A” or the letter “B.” After they had viewed the video,

we randomly assigned students to one of two groups by shuffling the response sheets and

distributing them to the class. Ten participants receiving form A were assigned to view a

sequential lineup (group A), and ten receiving form B subsequently viewed a simultaneous

lineup (group B).

After viewing the video, participants completed a short distractor task designed to take

approximately one minute in which they were asked to write the names of a number of animals

backwards. Then, confederates took group B participants outside of the classroom, and showed

them a simultaneous lineup of suspect photographs. Group A remained in the classroom and

viewed a sequential lineup. Afterward, both groups filled out their response sheets. Finally, we

debriefed participants and collected their responses.

A majority of participants did not complete the response sheets according to the

directions and did not eliminate any suspects. However, all participants indicated their level of

certainty for one or more of the suspects in the lineup. For participants who crossed off at least

one suspect according to the directions, we scored the total number of eliminations of innocent

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suspects (correct rejections). For participants who did not cross off any suspects, but did indicate

their level of certainty, we counted every incidence of “very” as a rejection. Because one suspect

was guilty (S2), each participant's total correct rejection score could range from zero to five.

Data comparing the scores of group A and group B were analyzed using a one-tailed

independent-samples t-test.

Results

There was a significant difference in the mean number of correct suspect rejections

between sequential group A (M = 4.3, SD = 0.82), and the simultaneous group B (M = 3.4, SD =

1.26), t (18) = 1.89, p = .04. One participant in group A and two participants in group B

eliminated the guilty suspect, scored as an incorrect rejection. Five participants in group A and

two participants in Group B identified the guilty suspect by making five correct rejections (see

Table 1).

Table 1

Frequencies of correct rejections by participants in groups A and B

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Group 0 1 2 3 4 5

A: Sequential 0 0 0 2 3 5

B: Simultaneous 0 1 1 3 3 2

Discussion

This experiment provides evidence for our hypothesis that using a sequential lineup may

lead to more correct rejections than using a simultaneous lineup. Additionally, the results do not

appear to contradict other research showing that lineup type has no affect on correct

identifications. Unfortunately, data collected on participant certainty could not be compared

between the two groups because of differences in which they followed the directions of the

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experiment.

A strength of this study was filming and using a video that led to sufficient variance in

participant responses. However, one serious limitation was that many participants misunderstood

the intended directions. This presented a challenge for us to code and score participant response

sheets, and may have increased the level of error in our results. Another limitation was that some

participants in both groups revisited and changed their first responses. This is problematic to

many of the assumptions of the sequential lineup.

Future studies of the differences in correct rejections between sequential and

simultaneous lineups should address these limitations. The directions for participants on response

sheets must be clearer, and the sheets themselves should be redesigned so it is more obvious how

they are intended to be used. Proctors should directly demonstrate to participants what is

expected of them, and be available for questions and concerns. With the aforementioned changes,

a follow-up experiment could also vary the presence of the guilty suspect in a lineup, which has

been shown to interact with the type of lineup used.

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References

Carlson, C. A., Gronlund, S. D., & Clark, S. E. (2008). Lineup composition, suspect position,

and the sequential lineup advantage. Journal of Experimental Psychology: Applied, 14(2),

118-128.

Jenkins, R., Lavie, N., & Driver, J. (2005). Recognition memory for distractor faces depends on

attentional load at exposure. Psychonomic Bulletin & Review, 12(2), 314-320.

Kneller, W., Memon, A., & Stevenage, S. (2001). Simultaneous and sequential lineups: Decision

processes of accurate and inaccurate eyewitnesses. Applied Cognitive Psychology, 15(6),

659-671.

Sharps, M. J., Hess, A. B., Casner, H., Ranes, B., & Jones, J. (2007). Eyewitness memory in

context: Toward a systematic understanding of eyewitness evidence. Forensic Examiner,

16(3), 20-27.

Steblay, N., Dysart, J., Fulero, S., & Lindsay, R. C. L. (2001). Eyewitness accuracy rates in

sequential and simultaneous lineup presentations: A meta-analytic comparison. Law and

Human Behavior, 25(5), 459-473.

Wells, G. L. (1993). What do we know about eyewitness identification? American Psychologist,

48(5), 553-571.