the effect of post-identification feedback on the recall of crime and perpetrator details

APPLIED COGNITIVE PSYCHOLOGYAppl. Cognit. Psychol. 19: 935–951 (2005)

Published online 16 June 2005 in Wiley InterScience(www.interscience.wiley.com) DOI: 10.1002/acp.1132

The Effect of Post-Identification Feedback on the Recallof Crime and Perpetrator Details

SUSAN DIXON* and AMINA MEMON

University of Aberdeen, UK

SUMMARY

The present study examines the effect of identification feedback on the quantity and accuracy ofcrime event details recalled, willingness to attempt misleading questions and confidence in theaccuracy of these details. All participants (N¼ 60) viewed a short video clip of a staged buildingsociety robbery and then made a false identification of the robber from a target-absent photospread.Eyewitnesses were next given confirming feedback (i.e. told that they had identified the suspect),disconfirming feedback (i.e. told that they had failed to identify the suspect) or no feedback. Alleyewitnesses then attempted a series of short-answer questions relating to details about the robber,accomplice, victim, building society, theft and getaway. Disconfirming feedback significantlyreduced eyewitness confidence in recall accuracy but there was no significant effect of feedbackon the overall quantity and accuracy of details recalled or willingness to attempt misleadingquestions. The theoretical implications of these results are discussed. Copyright# 2005 John Wiley& Sons, Ltd.

Eyewitness testimony can place a suspect at the scene of a crime at the time it was

committed and therefore often takes precedence over circumstantial evidence in the

courtroom (Wells et al., 1998). This emphasis on eyewitness evidence raises prominent

concerns, as highlighted by the numerous cases in which DNA evidence has exonerated

wrongly convicted persons. An investigation of 110 such cases in America revealed that

two-thirds of the inmates had been convicted on the basis of mistaken eyewitness

testimony, 11 of whom were on death row (Wells, 2004). Due to the seriousness of

such wrongful convictions, legal clinics such as the Innocence Project in New York have

been established to investigate cases in which DNA exoneration may prove to be a

wrongfully convicted person’s last hope. However, the task of assessing eyewitness

credibility is made very difficult by variables which can have an impact on eyewitness

identification accuracy (Wells, 1978). In the case of Neil v. Biggers (1972) the US Supreme

Court outlined criteria to be used by the jury in the assessment of identification evidence,

one of which is eyewitness certainty in his/her identification (see Wells & Murray, 1983,

for a detailed review of these criteria). However, the assumed relationship between

certainty and accuracy has become the subject of great scrutiny. The ‘irony of Biggers’

Copyright # 2005 John Wiley & Sons, Ltd.

*Correspondence to: S. Dixon, School of Psychology, William Guild Building, University of Aberdeen, King’sCollege, Aberdeen, AB24 2UB, Scotland. E-mail: [email protected]

(Wells & Bradfield, 1998) is that courts draw a jury’s attention to this factor, but it can be

greatly misleading.

Increased eyewitness confidence increases the likelihood that the suspect will be

charged and decreases the ability of the defence to suppress such a motion (Bradfield,

Wells, & Olson, 2002). Confidence is used as an indicator of identification accuracy by

judges, lawyers and laypersons (Penrod & Cutler, 1995). Most worrying is the impact of

eyewitness confidence on juries—those who ultimately determine the fate of the

defendant. ‘Juries appear to overbelieve eyewitnesses, have difficulty reliably differentiat-

ing accurate from inaccurate eyewitnesses’ and ‘are not adequately sensitive to aspects of

witnessing and identification conditions that are arguably better predictors of witness

accuracy than is witness confidence’ (Penrod & Cutler, 1995, p. 830). For example, mock

jurors tend to find a defendant guilty following a testimony by a confident eyewitness

irrespective of testimonial consistency (Brewer & Burke, 2002).

However, eyewitness confidence is malleable and not a simple function of identification

accuracy (Wells et al., 2000). There are conditions that can increase the confidence-

accuracy relationship; for example, when eyewitnesses correctly identify the target

(Lindsay, Read, & Sharma, 1998). In contrast, some have found the relationship between

confidence and accuracy to be weak (see Sporer, Penrod, Read, & Cutler, 1995, for a

review) and distorted by a variety of post-event variables. In addition, certain factors

can influence confidence and memory independently, which further distorts the con-

fidence-accuracy relationship (Wells, Olson, & Charman, 2002). For example, Memon,

Hope, and Bull (2003) investigated the relationship between duration of exposure to the

culprit and identification accuracy and confidence and found no difference in the

confidence ratings of accurate and inaccurate witnesses. ‘Eyewitness confidence is readily

influenced by social factors that can operate independently of perceptual and memorial

processes’ (Luus & Wells, 1994, p. 714). For example, in criminal investigations, the

lineup administrator is often the case detective (Wells, Olson, & Charman, 2003) who will

be aware of the position of the suspect in the lineup. Therefore, he or she may

(perhaps unconsciously) give an encouraging smile or disapproving frown as the eye-

witness approaches or ignores the suspect during the lineup task, thus influencing

eyewitness identification confidence (Garrioch & Brimacombe, 2001). These findings

suggest that eyewitnesses are susceptible to subtle cues from a lineup administrator who

holds particular beliefs as to who is the culprit. However, sometimes the administrator may

give more explicit cues, such as verbal feedback, regarding identification accuracy (Wells

& Bradfield, 1998). In the recent case of Holland v. HM Advocate (2004) in Scotland, an

eyewitness who had made a false identification from an identification parade was

subsequently informed by a police officer that she ‘had not done very well’. The

eyewitness later identified the accused in court during a dock identification and

the accused was found guilty. A consequent appeal by the defence included reference

to the non-disclosure of the remark by the police officer but the appeal was refused. This

case illustrates the potentially serious consequences of post-identification feedback. The

present study aims to extend present research in this area by investigating the effect of

feedback on the recall of specific crime details.

In the original study by Wells and Bradfield (1998), adult participants viewed a short

clip of security camera footage involving a gunman. Participants were required to identify

the culprit from a target-absent lineup (i.e. the culprit was not present in the lineup) and at

this point, were randomly allocated to one of three feedback conditions; confirming

(‘Good. You identified the actual suspect in the case.’), disconfirming (‘Oh. You identified

936 S. Dixon and A. Memon

Copyright # 2005 John Wiley & Sons, Ltd. Appl. Cognit. Psychol. 19: 935–951 (2005)

number ______. The actual suspect is number ______.’) or no feedback. The confirming

feedback increased eyewitness ratings of identification confidence and disconfirming

feedback reduced confidence relative to controls. Furthermore, feedback also distorted

retrospective reports of the ‘witnessing experience’. Specifically, witnesses in the

confirming condition reported a better view of the culprit, increased ability to identify

specific facial features of the culprit, increased attention to the event, a stronger basis for

making an identification, less time to make an identification, increased ease of identifica-

tion and increased willingness to testify. Although an eyewitness’ identification certainty

is used as a key indicator of identification accuracy, this study suggests that certainty can

be distorted by feedback administered after the identification task itself. Once feedback

has been administered, any subsequent attempt to recollect these aspects of the event will

be influenced by the feedback, as eyewitnesses are unlikely to have formed such

judgements ‘on-line’ during the witnessing experience (Wells & Bradfield, 1998).

Thus far, it has been shown that post-identification feedback can affect identification

certainty and general recollections of the witnessing experience. However, in what way

would feedback affect eyewitnesses who are cross-examined about specific details

regarding the perpetrator and crime event? Wells and Bradfield (1998) found that

confirming feedback increased the number of details given relating to the perpetrator

(i.e. the target). However, the accuracy of responding was not assessed and the study did

not investigate recall for other aspects of the crime such as physical actions, others

involved or details of the crime scene. Roper and Shewan (2002) compared eyewitness

recall accuracy before and after receiving false recall feedback and found participants

labelled as ‘Good Eyewitnesses’ after a first recall attempt subsequently showed a greater

improvement in recall accuracy than those labelled as ‘Poor Eyewitnesses’.

In addition to the recall of specific event details, Roper and Shewan also explored the

effect of feedback on eyewitnesses’ vulnerability to leading questions. They found that

participants told that they were ‘Poor Eyewitnesses’ were subsequently more susceptible

to leading questions than participants labelled as ‘Good Eyewitnesses’; therefore the effect

of feedback upon recall appears to be dependent upon question format. In a more recent

study by G. Davies, N. Robertson, H. Morton, and R. Jones (paper presented at the

European Association for Law and Psychology Conference, Krakow, 2004), eyewitnesses

were either informed that their free recall attempt was ‘accurate and complete’ (positive

feedback) or ‘pretty inaccurate and incomplete’ (negative feedback). Again, negative

feedback increased vulnerability to leading questions but had no effect upon the answering

of non-leading specific questions, which further suggests an apparent dissociation

regarding the effect of feedback upon leading and non-leading questions.

The effects of identification feedback on the recall of crime and perpetrator details

is important to investigate as an eyewitness who provides a greater number of details in

his/her testimony is perceived as more credible by a jury (Bell & Loftus, 1989; Leippe,

1994). Furthermore, even the inclusion of trivial details unrelated to the culprit can

increase judgements of guilt (Bell & Loftus, 1989). Although juries heavily rely on

identification certainty, ‘a witness who negotiates his/her way through such questioning

while maintaining confident responses to questioning will have a greater impact than

one who is assessed only on the basis of a confident identification’ (Brewer & Burke,

2002, p. 362).

The present study aimed to investigate the effect of post-identification feedback on

eyewitness recall of specific crime and perpetrator details. In particular, the effect of

feedback on (1) the quantity and accuracy of responses to questions regarding the crime

Feedback and the recall of crime event details 937


and perpetrator; (2) willingness to attempt misleading questions for the witnessed event;

and (3) eyewitnesses’ confidence in the accuracy of these details.

METHOD

Participants

Sixty first year undergraduate psychology students were recruited from the University of

Aberdeen and received course credit for their participation. Participants were Caucasian

and aged between 17 to 26 years (M¼ 18.7, SD¼ 1.7). There were 24 males and 36

females. English was the first language of all participants.

Design

In a between-participants design, participants viewed a video clip of a staged robbery and

were then administered with biased lineup instructions, forcing them all to make an

identification of the robber from a target-absent lineup.1 This produced a 100% false

identification rate, thus eliminating identification accuracy as a complicating factor from

the data analyses (Wells & Bradfield, 1998). Participants were then randomly assigned to

one of three post-identification feedback conditions (confirming, disconfirming, or no

feedback). Participants in the confirming group were told that they had correctly identified

the suspect; participants in the disconfirming group were told that they had incorrectly

identified the suspect; and those in the control condition received no post-identification

feedback at all. A post-identification questionnaire was used to assess the recall of crime

and perpetrator details (i.e. the quantity and accuracy of details recalled). Participants’

confidence in the accuracy of the details they recalled was measured on a Likert scale

(0¼ not at all confident; 10¼ extremely confident).

The verbal feedback employed in this study was a modified version of that used by

Wells and Bradfield (1998) and its influence was initially assessed in a pilot study

(N¼ 19). However, the verbal feedback manipulation created no differences in the

quantity or accuracy of details recalled or confidence in recall ability, thus suggesting

that the feedback was not strong enough or was not being sufficiently acknowledged by the

participants. Therefore, emphasis was added to the feedback. In addition to the verbal

feedback, immediately after the identification task the experimenter wrote ‘Good Eye-

witness’ at the top of the post-identification questionnaire for those in the confirming

condition and ‘Poor Eyewitness’ on the questionnaire of those in the disconfirming

condition (as described in Roper & Shewan, 2002). In the present study this ‘label’

immediately followed the verbal feedback to make it clear to participants that it referred to

their identification performance.

Materials

Crime video

The video stimulus employed was that used by Memon et al. (2003). Following an

evaluation by independent raters, the video was edited to ensure that ease of identification

1In a real-world situation however, an eyewitness should always receive unbiased lineup instructions, whichinform the eyewitness that the suspect may or may not be in the lineup.



was such that the identification feedback manipulation would be feasible. It was revealed

that the ability to make an identification based on the video clip was judged at

approximately 50%; therefore the video was suitable as a basis on which to provide

false feedback to eyewitnesses about their identification performance. If it had been

impossible to see the robber or if the robber had been clearly visible for too long a

duration the results may have been a function of viewing conditions rather than the

feedback effect.

The short video clip depicted a reconstruction of a building society robbery involving

professional actors. The camera follows a smartly dressed Caucasian male (main

robber) as he approaches and enters the building society. He waits in the queue before

taking a seat at one of the cashier desks and immediately shows the female cashier a

demand note, the contents of which are clearly visible. The robber also produces an item,

which appears to be a gun although this is not revealed. After receiving a bag of money,

the robber then walks out of the building and enters a getaway vehicle, followed by a

male accomplice who was also seen standing in the queue. There are clear profile and

frontal views of the main robber’s face (i.e. the target), which is exposed for

approximately 18 s.

Photographic lineup

Participants were presented with a simultaneous, target-absent lineup (i.e. it did not

contain the culprit). The lineup comprised frontal view head shots of six men. All six foils

were selected on the basis of their physical similarity, as assessed by independent

eyewitnesses (see Memon et al., 2003, for a detailed description of this selection

procedure).

Post-lineup questionnaire

A 25-item questionnaire based on the video clip assessed the quantity and accuracy of

crime and perpetrator details recalled. The questionnaire comprised six sub-sections, each

relating to a different aspect of the witnessed event. These included ‘Robber’ (e.g. ‘What

colour was the robber’s hair?’), ‘Accomplice’ (e.g. ‘What item of clothing did the acco-

mplice wear on his upper body?’), ‘Building Society’ (e.g. ‘What was the name painted on

the outside of the building society?’), ‘Theft’ (e.g. ‘What did the cashier put the stolen

money into?’), ‘Victim’ (e.g. ‘What colour was the cashier’s blouse?’) and ‘Getaway’ (e.g.

‘What was the registration number of the getaway vehicle?’). The final question in each

sub-section of the questionnaire was ‘misleading’ (i.e. the question suggested an item was

present in the video when it was not, or they were impossible to answer and required a

guess or estimation). For example, witnesses were asked, ‘In addition to stealing the

money, what other item did the robber steal from the cashier’s desk?’ but the robber did not

steal any additional item. The ‘Robber’ sub-section contained two such questions. On

completion of each sub-section, participants rated their confidence in the accuracy of their

responses on a Likert scale (0¼ not at all confident; 10¼ extremely confident).

Procedure

All participants were tested individually and were informed that the study was an

investigation of eyewitness perceptions of events. All participants were shown the short



video clip and immediately afterwards, were presented with the following series of ‘filler

tasks’: NEO Five-Factor Inventory (Costa & McCrae, 1992); Gudjonsson Compliance

Scale (Gudjonsson, 1989); Aberdeen Metamemory Questionnaire (A. Memon, L. Hope, &

F. Gabbert, paper presented at the biennial meeting of the American Psychology-Law

Society, Austin, Texas, 2002); Self-Consciousness Scale (Fenigstein, Scheier, & Buss,

1975); Doors Test Baddeley, Emslie, & Nimmo-Smith, 1994); Self-Ordered Pointing Task

(Shimamura & Jurica, 1994); and the Initial Letter Fluency Task (Benton, 1968). Note that

there were no significant differences across groups for those measures that may have

directly influenced susceptibility to the feedback manipulation, such as agreeableness (a

sub-component of the NEO-Five-Factor Inventory) and compliance (Gudjonsson Com-

pliance Scale). The completion of these tasks created a delay of approximately 35min

between witnessing the crime event and attempting to make an identification of the robber.

Participants were then administered with the photographic lineup and instructed to

identify the person they saw commit the robbery (i.e. participants were led to believe that

the target was present in the lineup, but he was absent). Identifications were made by

circling the letter on a response sheet that corresponded with the letter of the chosen

photograph. There were no time restrictions as to how long participants were allowed to

view the photographic lineup and all participants made a response without the need for

further encouragement from the experimenter to do so.

Participants were then randomly assigned to the confirming, disconfirming or no

feedback condition. Participants in the confirming-feedback condition were told, ‘Good.

You identified the actual suspect. Very few people have managed to do this successfully.’

Participants in the disconfirming-feedback condition were told, ‘Oh. You identified letter

______. Actually, that is wrong. The correct answer is letter _______.’ In the no feedback

(control) condition, the experimenter said ‘OK’ after the participant had made their

response without looking at the participant’s response sheet; no feedback was given

regarding the identification decision. Participants were then administered with the post-

lineup questionnaire. In the confirming-feedback trials, the experimenter wrote ‘Good

Eyewitness’ at the top of the questionnaire in red capital letters and in the disconfirming-

feedback trials, the experimenter wrote ‘Poor Eyewitness’. Nothing was written on the

questionnaire in the control trials; it was simply placed in front of participants. Participants

were informed that the questionnaire comprised questions based on the video clip that they

had viewed earlier. They were told to try to attempt each question but if they did not know

the answer to a question, they were to tick the ‘don’t know’ option. Participants then

completed a manipulation check sheet, in which they stated what they believed to be the

aim of the study and whether they were suspicious at any point. All participants were

unaware of the true aim of the experiment and no participants expressed suspicion

regarding the purpose of the study. Finally, participants were fully debriefed and thanked

before leaving the laboratory.

RESULTS

As stated, this study aimed to investigate the effect of post-identification feedback on the

recall of crime and perpetrator details. This involved a comparison of the quantity of

recall, accuracy of recall and attempts to answer misleading questions across conditions.

This study also explored the effects of feedback on participants’ ratings of confidence in

the accuracy of the details recalled.



The effect of feedback on the quantity of details recalled

Initially, it was of interest to establish whether feedback influenced the mean number of

answers (i.e. questions to which the participant provided a written response) and the mean

number of ‘don’t know’ responses.2

(i) Total quantity of information recalled

This analysis compared participants’ responses to all 18 questionnaire items. As shown in

Table 1, the disconfirming group provided the highest number of answers and the

confirming group provided the lowest number of answers. However, a one-way Analysis

of variance (ANOVA) revealed that there was no significant effect of feedback on the

number of answers provided, F(2, 57)¼ 0.635, p¼ 0.53. Table 2 shows that the confirming

group provided the highest number of ‘don’t know’ responses and the disconfirming group

provided the lowest number of ‘don’t know’ responses. Again the effect of feedback was

not significant, F(2, 57)¼ 0.517, p¼ 0.60.

(ii) Quantity of information recalled for each questionnaire sub-section

This involved a comparison of the mean number of answers and ‘don’t know’ responses

for each of the six sub-sections of the questionnaire (see Tables 1 and 2 respectively). A

one-way ANOVA revealed that the effect of feedback on the number of answers for each

sub-section was not significant, all ps� 0.16. There was also no significant effect of

feedback on the number of ‘don’t know’ responses for each sub-section, all ps� 0.30.

(iii) Reason for ‘don’t know’ responses

The original Wells and Bradfield (1998) study did not examine why participants responded

‘don’t know’ so it is unclear whether these responses may actually be a function of the

feedback manipulation or due simply to genuine poor memory. Thus, in the present study,

Table 1. The effect of post-identification feedback on the number of answers provided

Mean number of answers in each questionnairesub-section and total mean number of answers for each condition

Feedback Buildingcondition Robber Accomplice society Theft Victim Getaway Total

DisconfirmingM 3.35 1.60 0.10 2.00 1.85 3.80 12.70SD 0.67 0.68 0.31 0.00 0.37 1.15 1.95

NoneM 2.90 1.45 0.20 2.00 1.60 3.90 12.10SD 0.72 0.76 0.41 0.00 0.60 1.65 2.81

ConfirmingM 2.95 1.35 0.35 1.95 1.55 3.55 11.80SD 1.10 0.88 0.49 0.22 0.69 1.36 2.86

2The analyses on both the quantity and accuracy of recall were conducted on the 18 non-misleading questionsonly. This is because it was not possible to code the misleading questions as correct or incorrect (these wereimpossible to answer based on the video clip). The effect of feedback on attempts to answer the eightmisleading questions is discussed separately.



for each ‘don’t know’ response participants were asked if they had been unwilling to

provide an answer (i.e. due to being unsure of their answer, as opposed to having no

memory at all) or if they simply had no memory for the item (i.e. simply could not

remember). The total number of ‘no memory’ and ‘unwilling’ replies for the ‘don’t know’

responses were converted into percentages of the total number of ‘don’t know’ responses

for each group. Percentages of ‘no memory’ and ‘unwilling’ replies were also obtained for

the ‘don’t know’ responses within each of the six sub-sections. There was no significant

effect of feedback on the total number of ‘no memory’, F(2, 57)¼ 0.026, p¼ 0.97, or

‘unwilling’ responses, F(2, 57)¼ 1.014, p¼ 0.37, or on the number of ‘no memory’ or

‘unwilling’ responses within each sub-section of the questionnaire, all ps� 0.13.

The effect of feedback on the accuracy of details recalled

The second aim of this study was to assess the effect of feedback on the accuracy of the

details recalled. Inevitably, participants in each condition did not provide the same number

of answers; thus it was necessary to convert the number of correct and incorrect responses

into a percentage of the total number of answers for each participant. The analyses for

accuracy were based on the mean percentage of correct and incorrect answers in each

condition. For this reason, the percentages of correct and incorrect answers for each group

do not add up to 100%.

(i) Total accuracy

All correct answers for each sub-section were added together to produce a total number of

correct answers, which was then converted into a percentage of the total number of

answers provided. This was repeated for incorrect answers to generate a total mean

percentage of correct and incorrect answers for each condition. As shown in Table 3, the

disconfirming group provided the highest percentage of correct answers and the control

group provided the lowest percentage of correct answers. Table 4 shows that the control

group provided the highest percentage of incorrect answers and the disconfirming group

provided the lowest percentage of incorrect answers. However, the effect of feedback on

the percentage of correct answers and incorrect answers was not significant, both

F(2, 57)¼ 2.587, p¼ 0.08.

Table 2. The effect of post-identification feedback on the number of ‘don’t know’ responsesprovided

Mean number of ‘don’t know’ responses in each questionnaire sub-sectionand total mean number of ‘don’t know’ responses for each condition



NoneM 1.10 0.55 1.80 0.00 0.45 1.05 4.95SD 0.72 0.76 0.41 0.00 0.69 1.64 2.82

ConfirmingM 1.00 0.65 1.70 0.05 0.50 1.40 5.30SD 1.03 0.88 0.57 0.22 0.76 1.31 2.98



(ii) Accuracy of information recalled for each questionnaire sub-section

This involved a comparison of the mean percentage of correct answers (see Table 3) and

incorrect answers (see Table 4) for each of the six sub-sections of the questionnaire. There

was no significant effect of feedback on the mean percentage of correct answers, all

ps� 0.10. There was a significant effect of feedback on the mean percentage of incorrect

answers only for questions relating to ‘Building Society’, F(2, 57)¼ 3.304, p¼ 0.04,

MSE¼ 0.467, �p2¼ 0.10. A Tukey test revealed only a significant difference between the

confirming and disconfirming conditions, p¼ 0.04, indicating that the confirming group

provided a significantly higher number of incorrect answers for questions relating to

‘Building Society’.

Willingness to attempt misleading questions

A one-way ANOVAwas employed to compare the mean number of misleading questions

attempted by participants in the confirming, disconfirming and no feedback conditions.

There was no effect of feedback on participants’ willingness to answer misleading

questions, F(2, 57)¼ 0.315, p¼ 0.73.

Table 3. The effect of post-identification feedback on the percentage of correct answers provided

Mean percentage of correct answers in each questionnaire sub-sectionand total mean percentage of correct answers for each condition



NoneM 70.42 22.50 5.00 70.00 37.50 41.33 49.69SD 29.43 34.32 22.36 25.13 42.54 26.95 15.29

ConfirmingM 67.08 25.00 0.00 77.50 52.50 41.75 53.05SD 36.72 34.41 0.00 25.52 41.28 28.59 16.53

Table 4. The effect of post-identification feedback on the percentage of incorrect answers provided

Mean percentage of incorrect answers in each questionnaire sub-sectionand total mean percentage of incorrect answers for each condition



NoneM 29.58 62.50 15.00 30.00 57.50 55.33 50.31SD 29.43 42.54 36.64 25.13 43.76 29.88 15.29

ConfirmingM 37.92 50.00 35.00 22.50 37.50 53.25 46.95SD 38.76 42.92 48.94 25.52 39.32 29.63 16.53



The effect of feedback on confidence for details recalled

A further aim of this study was to examine the influence of post-identification feedback on

participants’ confidence in the accuracy of the details they recalled. Analyses explored

total confidence and confidence for each aspect of the crime event.

(i) Total confidence

The mean confidence ratings for each of the six sub-sections (‘Robber’, ‘Accomplice’,

‘Building Society’, ‘Theft’, ‘Victim’ and ‘Getaway’) were pooled to produce a ‘Total’

mean confidence rating. As shown in Figure 1, the disconfirming group was less confident

than the confirming and control groups. The effect of feedback on confidence was

significant, F(2, 57)¼ 4.474, p¼ 0.02, MSE¼ 271.267, �p2¼ 0.14. A Tukey test showed

a significant difference between the confidence rating of the confirming and disconfirming

groups, p¼ 0.05, and also the disconfirming and control groups, p¼ 0.02, showing that the

disconfirming group was significantly less confident. There was no significant difference

between the control and confirming conditions.

(ii) Confidence in the accuracy of recall for each questionnaire sub-section

This analysis compared mean confidence ratings for each of the six sub-sections across

conditions (see Table 5).

The effect of feedback was significant for three of these six sub-sections, namely

‘Robber’ (F(2, 57)¼ 4.909, p¼ 0.01, MSE¼ 17.117, �p2¼ 0.15), ‘Theft’ (F(2, 57)¼

4.376, p¼ 0.02, MSE¼ 13.617, �p2¼ 0.13) and ‘Victim’ (F(2, 57)¼ 5.789; p¼ 0.01,

MSE¼ 12.950, �p2¼ 0.17). A Tukey test showed that the confirming group was signifi-

cantly more confident than the disconfirming group for ‘Robber’ ( p¼ 0.01) and ‘Theft’

( p¼ 0.02) details. For details regarding the ‘Victim’, the control group was significantly

more confident than the disconfirming group, p¼ 0.004.

Eyewitnesses’ perceptions of the effect of feedback

After completing the post-lineup questionnaire, participants reported whether or not they

believed the feedback had influenced their responses and confidence. It should be noted

0

5

10

15

20

25

Disconfirming No feedback Confirming

Feedback condition

Tot

alm

ean

conf

iden

cera

ting

(%)

Figure 1. The effect of feedback on participants’ confidence in their accuracy of recall



that all participants initially acknowledged that they had been administered with

confirming or disconfirming feedback.

(i) Answering of the questions

Participants were asked whether they believed the feedback had influenced the way in

which they had answered the questions (response either ‘Yes’ or ‘No’). In the disconfirm-

ing group, 15 (75%) said ‘Yes’ and five (25%) said ‘No’. In the confirming group 10 (50%)

said ‘Yes’ and 10 (50%) said ‘No’. Thus, pooling the confirming and disconfirming data,

25 participants (62.5%) claimed that the feedback manipulation had exerted an influence.

However, there was no significant association between condition and perceived influence

of feedback, �2¼ 2.667, df¼ 1, p¼ 0.10, �¼�0.26.

Participants who responded ‘Yes’ were then asked to state whether the feedback had

made them ‘more cautious’ or ‘try harder’ when answering the questions. Twelve (80%) of

those in the disconfirming group said the feedback made them more cautious and three

(20%) said it made them try harder. In the confirming group, four (40%) said the feedback

made them more cautious and six (60%) said it made them try harder. There was a

significant association between condition and perceived influence of feedback on

responding, �2¼ 4.167; df¼ 1, p¼ 0.04, �¼�0.41.

(ii) Confidence

Participants were required to state whether they believed the feedback had influenced their

confidence in the accuracy of the details recalled. In the disconfirming group, 16 (80%)

said ‘Yes’ and four (20%) said ‘No’. In the confirming group, 12 (60%) said ‘Yes’ and

eight (40%) said ‘No’. Thus, pooling the confirming and disconfirming data revealed that

28 participants (70%) believed that the feedback manipulation had influenced confidence.

There was no significant association between condition and perceived influence of

feedback, �2¼ 1.905, df¼ 1, p¼ 0.17, �¼�0.22.

Participants who responded ‘Yes’ were asked whether feedback had increased or

decreased their confidence. All of those in the disconfirming group that had previously

stated the feedback influenced their confidence (N¼ 16) claimed it had been decreased. In

the confirming group, nine participants (75%) said the feedback had increased their

Table 5. The effect of post-identification feedback on participants’ confidence in their accuracy ofrecall

Mean confidence rating in each questionnaire sub-sectionand total mean confidence rating for each condition



NoneM 3.30 3.45 2.55 3.65 3.75 3.15 19.85SD 1.72 2.06 1.73 1.42 1.33 1.57 7.53

ConfirmingM 4.25 2.90 1.95 4.10 2.80 3.15 19.15SD 2.31 2.61 2.09 2.15 1.74 1.90 8.67



confidence and three (25%) claimed it had been decreased. There was a significant

association between condition and perceived influence of feedback on confidence,

�2¼ 17.684, df¼ 1, p¼ 0.001, �¼ 0.79.

DISCUSSION

The results show that feedback did not significantly affect the quantity or accuracy of

crime and perpetrator details recalled. In addition, feedback did not influence eye-

witnesses’ willingness to attempt misleading questions, which contradicts previous

findings (G. Davies et al., paper presented at the European Association for Law and

Psychology Conference, Krakow, 2004; Roper & Shewan, 2002). However, it is possible

that feedback would influence the recall of crime and perpetrator details if administered by

an individual with greater authority than the student in the present study, such as a

uniformed police officer. Indeed, interviewer status has previously been found to affect

susceptibility to leading questions (G. Davies et al., paper presented at the European

Association for Law and Psychology Conference, Krakow, 2004).3 In the current study,

those who received disconfirming feedback demonstrated significantly lower levels of

confidence in the accuracy of their recall. The lowered confidence of those in the

disconfirming condition cannot be attributed to poor memory for the event, as recall did

not significantly differ across the conditions. Furthermore, participants were randomly

allocated to the feedback condition after having witnessed the crime event under the same

viewing conditions, suggesting that the decreased confidence was likely due to the

feedback manipulation as opposed to witnessing conditions.

A number of possible theories may explain the deflation of confidence evident in the

disconfirming feedback condition. One such account is ‘hindsight’ (Fischhoff, 1975), a

process in which knowledge as to the outcome of an event influences perceptions of the

situation leading up to this output information. In the present study, eyewitnesses who

were told that they had failed to identify the perpetrator may reason that they did not pay

sufficient attention to the details of the event. Therefore, although the quantity and

accuracy of their recall were unaffected, the disconfirming feedback caused eyewitnesses

to doubt their recall ability, thus influencing their subjective confidence ratings. However,

this does not account for the finding that confirming feedback did not increase confidence.

Therefore, perhaps the disconfirming feedback exerted an influence for a reason other than

hindsight. For example, it may be that disconfirming feedback has a greater emotional

impact than confirming feedback (Luus & Wells, 1994) as making the ‘wrong’ identifica-

tion decision and being labelled as a ‘Poor Eyewitness’ may also carry a social stigma and

notion of failure. Furthermore, it may be that relative to confirming feedback, people

believe that disconfirming feedback has a greater impact on how we are perceived by

others in society and therefore has a greater influence on one’s confidence. An alternative

interpretation is based on the claim that people naturally assume that they are good at

recognizing faces (Leippe, 1980). Informing someone that they picked the wrong person

from a lineup task (i.e. disconfirming feedback) challenges a belief that individuals take

3It is also possible that the heterogeneous format of the questions (i.e. the inclusion of both leading and non-leading questions) may have affected the impact of feedback upon recall attempts and accuracy, thus futurestudies should investigate the effect of feedback on non-leading questions using a consistent question format.



for granted and may therefore have more impact than confirming feedback, which merely

reinforces this belief. These interpretations should be investigated in future research.

The original Wells and Bradfield (1998) paradigm demonstrated a greater effect for

confirming feedback on subsequent eyewitness confidence reports regarding identification

choice. However, the present study suggests that it is easier to deflate eyewitness

confidence regarding ability to recall specific details pertaining to the crime event and

perpetrator. It is also interesting to note that details concerning the robber were recalled

with least confidence by those in the disconfirming condition. This makes sense as the

feedback was directly related to the eyewitness’ ability to identify the robber; thus

eyewitnesses may have also applied this feedback to their ability to recall other details

about the robber.

Despite the lack of a significant effect of feedback on the quantity or accuracy of

details recalled, half of those in the confirming group and three-quarters of those in the

disconfirming group believed the feedback had influenced their performance. This

confirms earlier research that suggests people are unable to make accurate introspective

judgements about the factors that influence their behaviour (Nisbett & Wilson, 1977). In

contrast, the majority of those in the disconfirming condition believed that the feedback

had decreased their confidence and this was found to be the case. Thus, eyewitnesses

were aware of the effect of feedback on their confidence. However, over half of those in

the confirming condition believed that the feedback had inflated their confidence,

although no differences in confidence ratings were found relative to controls. It may

have been that the disconfirming feedback was more meaningful and personal to

eyewitnesses, exerting a genuine, perceived influence. In contrast, those in the confirm-

ing condition may have reported that feedback influenced confidence in an attempt to

‘please’ the experimenter by providing the response they believed to be most appropriate

(Rosenthal, 1976).

In sum, it appears that feedback can alter eyewitness confidence without influencing

testimonial accuracy. Wells and Bradfield (1999) found that post-identification feedback

affects identification confidence without influencing accuracy and the present study has

revealed a similar effect of feedback in relation to recall confidence and accuracy. This

dissociation regarding the effect of feedback on accuracy and confidence is referred to as

the ‘confidence main-effect problem’ (Luus & Wells, 1994, p. 715). The question is how

does one account for the differential effect of feedback on recall accuracy and confidence?

Wells and Bradfield (1998) argued that during the crime event, eyewitnesses do not form

‘on-line’ judgements as to how good a view they have of the robber, how much attention is

being paid, how many seconds the perpetrator’s face is in view and so on. If eyewitnesses

do not consider these aspects at the time of the crime, they have no record of these

judgements to refer back to; therefore the memory trace for these aspects is poor.

Consequently, if an eyewitness receives post-identification feedback and is then asked

to recollect these judgements, the eyewitness relies on the feedback as an ‘internal cue’ to

guide their judgements. Thus, eyewitness recollections of the ‘witnessing experience’ are

distorted by the feedback and do not reflect pure memory. This line of argument is based

on self-perception theory (Bem, 1972), which states that individuals base beliefs upon

their behaviour and its context when internal cues are weak or ambiguous. If one turns this

theory around, this may account for why feedback does not appear to influence the recall

of crime and perpetrator details. Details relating to the crime scene and the people

involved are explicitly visible while viewing a crime event and such details are therefore

encoded ‘on-line’. No implicit judgements are required to determine such details, unlike



recollections regarding view, attention, exposure time and so forth, which are more

subjective and therefore perhaps more susceptible to distortion. Consequently, internal

cues for crime and perpetrator details are strong, creating resistance against the effect of

feedback. However, this does not account for the fact that feedback did not influence

attempts to answer misleading questions. Therefore, alternative explanations for the data

will now be explored.

One possibility concerns the comparative difficulty of the recall and recognition tasks.

Wells and Murray (1983) claim that one’s recognition ability usually exceeds one’s ability

to recall items from memory. In the present study, biased lineup instructions forced all

participants to make a false identification and, in a target-absent lineup, the eyewitness

must simply select the foil that most closely resembles the perpetrator (Wells et al., 1998).

Therefore, the confirming group may have found this a relatively easy task and perceived

the recall task as more difficult in comparison. For this reason, participants may have been

reluctant to accept any external influence implying that they may perform well on the

recall of details. Similarly, those in the disconfirming condition may have simply

dissociated the recognition and recall tasks and thus resisted the suggestion that their

recall performance would inevitably be poor. It may be that feedback must be directly

related to the subsequent task in order to be influential and prior research supports this line

of reasoning. For example, Wells and Bradfield (1998) found that identification feedback

influenced identification certainty and Roper and Shewan (2002) found that feedback

regarding recall performance influenced subsequent recall attempts. The present study

investigated the effect of identification feedback on recall performance.

The present findings have shown that post-identification feedback can distort the

already weak relation between eyewitness accuracy and confidence. A major implication

of the present study is that an eyewitness’ confidence regarding his/her recall ability is

highly susceptible to social influence. No matter how confident eyewitnesses feel

regarding their ability to recollect a crime event, if another individual suggests that they

are incorrect regarding one aspect of that event, it can greatly deflate confidence. This may

also have repercussions in other areas of criminal investigation. For example, during the

hunt for the Oklahoma bomber, police selected the most confident witness to help in the

construction of an artist’s impression of the suspect (Memon &Wright, 1999). However, it

may be that the most accurate eyewitness was actually the one who had received some

form of negative feedback, which had caused the individual to doubt his/her ability as an

eyewitness. The vital message arising from studies such as these is the need to create

awareness regarding the malleability of eyewitness confidence throughout all levels of the

legal system.

Another point of concern stems from the work of Luus and Wells (1994). Eyewitnesses

told by the lineup administrator that they had made an identification decision different to

that of a co-witness reported lower levels of identification confidence than those told they

had made the same decision and continued to demonstrate reduced confidence even after

the lineup administrator claimed to have made a mistake (i.e. told them that they had

actually made the same decision). In other words, there were ‘perseverance effects’ (Luus

& Wells, 1994, p. 718). Perseverance effects may render it impossible to retract any initial

disconfirming feedback and, as shown in the present study, this can greatly deflate

eyewitness confidence. Consequently, an eyewitness may be accurate in both their

identification decision and recall of crime details, yet be doubted by the jury due to the

robust nature of the effect of feedback on confidence. This further stresses the need to

control feedback as a system variable within the judicial system.



There are a number of theoretical issues that should be addressed in future studies. For

example, Semmler, Brewer, and Wells (2004) found confidence inflation effects following

feedback for both eyewitnesses who had made accurate and inaccurate identifications,

which contrasts with previous research by Bradfield et al. (2002) which revealed that

confirming feedback had a greater impact on the retrospective reports of inaccurate

witnesses. Eyewitnesses who correctly identify the perpetrator are often less accurate in

their recall of peripheral details (Wells & Leippe, 1981), therefore it would be of interest to

include a target-present lineup and explore whether identification accuracy alters the effect

of feedback on the recall of crime and perpetrator details and confidence in recalled

details. A second aspect that would be of interest to investigate concerns the effect of

feedback on recall confidence following a greater delay between attempting the identifica-

tion and receiving the feedback (Luus &Wells, 1994; Wells et al., 2003;). If the delay was

extended from 35min to, for example 48 h, would the effect of disconfirming feedback on

recall confidence be mitigated, or would an effect of feedback on the actual recall of

details arise, due to a weakening of internal cues over time? In addition, misleading

questions in the present study required a complex answer. For example, eyewitnesses were

asked, ‘What did the cashier accidentally drop onto the floor in the building society?’

when, in fact, she did not drop anything at all. Therefore, eyewitnesses should have

responded, ‘I did not see the cashier drop anything’, if at all. In future research, such

questions could be presented in a format that requires a ‘yes’, ‘no’ or ‘don’t know’

response; for example, ‘Did the cashier drop an item on the floor of the building society?’

This would enable a measure of yield to be calculated (i.e. the number of ‘yes’ responses),

representing eyewitnesses’ susceptibility to comply with misleading questions after

receiving post-identification feedback (Gudjonsson, 1997).

The present study attempted to extend current understanding of the distorting influence

of post-identification feedback on eyewitness testimony. Although feedback did not affect

the recall of crime and perpetrator details, disconfirming feedback significantly deflated

eyewitnesses’ confidence in their ability to recall these details. Confidence is a key factor

in the evaluation of eyewitness credibility but is susceptible to distortion by social

influences of which juries are often completely unaware. The combination of these two

factors is an issue of concern for all those involved in legal proceedings and highlights the

need to pursue further research in this area.

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the effect of post-identification feedback on the recall of crime and perpetrator details

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