Law Hum Behav (2010) 34:186–197 DOI 10.1007/s10979-009-9179-7
ORIGINAL ARTICLE
Is Manipulative Intent Necessary to Mitigate the Eyewitness Post-Identification Feedback Effect? Deah S. Quinlivan Æ Gary L. Wells Æ Jeffrey S. Neuschatz
Published online: 28 April 2009 American Psychology-Law Society/Division 41 of the American Psychological Association 2009
Abstract Feedback suggestive of mistaken eyewitnesses claiming that they identified the correct person leads to distorted retrospective judgments of certainty, view, and other testimony-relevant measures. This feedback effect can be significantly mitigated if witnesses later learn that the feedback source did not know which lineup member was the correct person and had a manipulative intent (postfeedback suspicion manipulation). We replicated the postfeedback suspicion effect and used a mistake condition showing that the manipulative intent is not a necessary component, thereby ruling out reactance-type interpretations of the post-feedback suspicion effect. Some conditions included instructions to ensure relevant processing of the feedback before the post-feedback suspicion manipulations, but these processing instructions did not mitigate the effect. The results suggest that these retrospective judgments (e.g., certainty, attention, view) remain malleable as new information unfolds. Keywords Feedback Eyewitness malleability Suspicion Private thought Post-conviction forensic DNA testing has exonerated 226 innocent people who were convicted by juries and approximately 75% of these cases were of mistaken eyewitness identification (Scheck, Neufeld, & Dwyer, 2000; http:// www.innocenceproject.org). The prevalence of eyewitness
D. S. Quinlivan (&) G. L. Wells Department of Psychology, Iowa State University, West 112 Lagomarcino, Ames, IA 50011, USA e-mail:
[email protected] J. S. Neuschatz The University of Alabama in Huntsville, Huntsville, USA
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identification errors in these cases is consistent with the general view that eyewitness evidence is overvalued by jurors. It would be misleading, however, to assert that mistaken identifications per se lead to wrongful convictions; it would be more defensible to say that these wrongful convictions come from witnesses who are highly confident about their mistaken identifications—false certainty. The psychological literature has repeatedly demonstrated that jurors are willing to accept eyewitness identification testimony primarily when eyewitnesses are highly confident in their identification (e.g., Cutler, Penrod, & Dexter, 1990; Fox & Walters, 1986; Wells, Ferguson, & Lindsay, 1981). The DNA exoneration cases are consistent with this; highly confident witnesses who nevertheless were mistaken persuaded jurors. Indeed, it has been argued that jurors might not be so over-believing of eyewitnesses if eyewitnesses were not so overconfident (Wells, 1993). Hence, it is important to study the factors that contribute to false certainty and to explore factors that might mitigate the development of false certainty. A major factor that can contribute to false certainty is giving eyewitnesses feedback that seems to confirm their identification even though they actually identified the wrong person, an effect that is known as the post-identification feedback effect (Wells & Bradfield, 1998). The inflated levels of false certainty from post-identification feedback are largely eliminated, however, if the witness is encouraged to engage in private thought about his or her certainty prior to the feedback manipulation (Wells & Bradfield, 1999). More recently, however, research has shown that the post-identification feedback effect can be reduced dramatically even after the feedback manipulation if the participant is led to become suspicious of the feedback (Neuschatz et al., 2007; Quinlivan et al., 2009). In the interest of clarity, we will call the manipulation used by
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Neuschatz and his colleagues the post-feedback suspicion manipulation to make it clear that it occurs after feedback whereas the private thought manipulation used by Wells and Bradfield occurs before feedback. The focus of the current research is on the post-feedback suspicion effect. The effect of the post-feedback suspicion manipulation is surprising, especially in light of extensive work on perseverance effects in which false information tends to affect people’s judgments even after the information has been discredited (Anderson, 1995; Anderson & Lindsay, 1998; Ross, Lepper, & Hubbard, 1975). The current research introduces a critical new variation on the post-feedback discrediting effect to test the possibility that the effect is the result of reactance-like processes. In addition, the current research introduces a variation on the private-thought manipulation, which occurs after feedback, instead of before feedback. This post-feedback thought manipulation permitted us to test the hypothesis that post-feedback discrediting manipulations are effective only to the extent that the person has not engaged in relevant post-feedback processing. We first review the general findings, importance, and theoretical foundations of the post-identification feedback effect. Then, we review the pre-feedback thought technique and current conceptual foundations for how it is presumed to mitigate the effects of feedback. Then, we review the postfeedback suspicion effect. Based on these reviews, we introduce two hypotheses about how the post-feedback suspicion effect works and describe how we tested these hypotheses.
THE POST-IDENTIFICATION FEEDBACK EFFECT In recent years, the post-identification feedback effect has emerged as one factor that increases false certainty (see meta-analysis by Douglass & Steblay, 2006). As mentioned earlier, confirming post-identification feedback is any suggestion to the eyewitness that he or she has made a correct identification. The typical results are that participants who were given feedback report that they paid more attention to the perpetrator, are more certain in their identification, and had a clearer view when compared to the participants that were not given feedback.1 1
Of course, the demand characteristics concept is an overly flexible one and we cannot rule out the possibility that someone could spin a creative demand-characteristics interpretation. But, we argue that demand characteristics are not merely properties of the lab experiment but are inherent properties of the real world as well and, in that sense, are not experimental artifacts. We know, for example, that the post-identification feedback effect also works with actual witnesses (including victim witnesses) to serious crimes when real investigators debrief them on the status of the identified person (Wright & Skagerberg 2007). If there is a demand-characteristics component to the post-identification feedback effect, there is no reason to believe that it is restricted to the lab.
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On of the most interesting aspect of the post-identification feedback effect is that the effects are not restricted to certainty; post-identification feedback also distorts witnesses’ retrospective reports of how good their view during witnessing, how much attention they paid during witnessing, and numerous other identification-relevant judgments. The inflation of certainty, view, and attention are particularly important because jurors use these judgments to assess the accuracy of eyewitness identifications (Bradfield, Wells, & Olson, 2002; Cutler, Penrod, & Stuve, 1988; Fox & Walters, 1986; Wells, Lindsay, & Ferguson, 1979; Wells et al., 1981; Whitley & Greenberg, 1986). Furthermore, the U.S. Supreme Court specifically instructs lower courts to assess witnesses’ certainty, view, and attention as part of a reliability test for the identification (Manson v. Braithwaite, 1977). A strong argument has been made that the postidentification feedback effect reveals a critical flaw in the Manson v. Braithwaite ruling, which is the last time the Court issued a ruling on eyewitness identification issues (see Wells & Quinlivan, 2009). The Feedback Effect: Why Does It Occur? Why does the simple confirmation to a mistaken witness that they are accurate lead to false certainty? The dominant theoretical explanation for the post-identification feedback effect is that witnesses have little or no access to the cognitive traces formed at the time of witnessing (e.g., how good their view was) or at the time of the identification (i.e., how certain they were). Accordingly, participants’ self-reports to the retrospective confidence questions are inferences that participant witnesses construct at the time the judgments are elicited (Wells, Olson, & Charman, 2003). For example, participant-witnesses who are told they were accurate will reason that they must have been certain, they must have had a good view, and they must have paid attention; after all, they made the correct identification decision. The post-identification feedback effect therefore, occurs because the assessment of identification confidence occurs after the feedback and before the witness was able to make the assessments independent of the feedback. The reliability and robustness of the post-identification feedback effect is evidenced in a recent metaanalysis (Douglass & Steblay, 2006) and has now been shown to occur for actual witnesses and victims in real crimes (Wright & Skagerberg, 2007). This explanation for why the feedback effect occurs will be referred to as the accessibility/inference hypothesis. Several empirical observations are consistent with this accessibility/inference conceptualization (Neuschatz et al., 2007; Quinlivan et al., 2009; Wells & Bradfield, 1999). Recall, for example, that the post-identification feedback effect largely disappears if the witnesses’ cognitive traces
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(for certainty, attention, etc.) are elicited—via a private thought manipulation—prior to the exposure to feedback (Wells & Bradfield, 1999; and others). In the pre-feedback private thought manipulation—also referred to as the feedback prophylactic—participants were asked to think privately about how certain they were in their identification before they were randomly assigned to a feedback condition. This design allowed the researchers to examine the differences that occur when some participants were allowed to assess their confidence privately before the contamination of the feedback versus participants who were not given an opportunity to think about these variables independent of the feedback. Those who were allowed to think about their certainty before the feedback was administered did not demonstrate the typical confidence inflation effects from the feedback. Also consistent with the accessibility/inference hypothesis is the observation that participant-witnesses who report that they were not affected by the feedback manipulation show effects that are just as strong as those who report that they probably were affected (Wells & Bradfield, 1999). This suggests that participant-witnesses do not have access to their original (pre-feedback) traces of uncertainty and instead can only guess as to whether (and to what extent) they were affected. In addition, research shows that witnesses’ reports about how confident they currently feel (post feedback) are indistinguishable from their retrospective reports of how confident they recall having felt prior to getting the feedback (Semmler, Brewer, & Wells, 2004). It is tempting to postulate that the post-identification feedback effect more generally is the result of demand characteristics or impression-management motivations. There are two strong arguments, however, against such interpretations. First, the pre-feedback private thought manipulation serves to largely inoculate witnesses from the effects of feedback. If witnesses who are given confirming feedback merely wanted to ‘‘look good’’ by saying that they were certain all along, there is nothing in the prefeedback private thought manipulation that would prevent them from doing so (it was, after all, just their own private thoughts). In other words, all the same feedback demands and impression management motivations are present whether they engaged in private thought prior to feedback or not. Second, although it might be easy to consider certainty inflation as an impression management mechanism, why would confirming feedback lead witnesses to say that they had a better view? If they wanted to create a favorable impression, it seems that witnesses would boast that they were correct despite a poor view rather than because of it. Hence, we maintain the original view espoused by Wells and Bradfield (1998, 1999) that the processes underlying the post-identification feedback effect and its moderation
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are the result of attempts to genuinely reconstruct how certain they were at the time of identification, how good their view was, and so on, rather than an attempt to manage impressions or respond to demand characteristics. The Pre-Feedback Thought Effect: How Does It Prevent the Feedback Effect? Wells and Bradfield (1998) posit that judgments about certainty, view, and attention are inferences that are constructed at the time the judgments are elicited by an external source (i.e., retrospective confidence questionnaire). In other words, it is not the feedback itself that triggers the inference process, but instead the inference process is triggered by an external request for the retrospective judgments about the identification. Hence, relevant processing of the feedback (i.e., relevant to their judgments of certainty, view, and so on) should occur only when the witnesses reflect on their retrospective judgments. When relevant processing occurs prior to feedback, it creates a mental record (memory) of pre-feedback judgments that can then be used to answer the retrospective questions, thereby moderating the effects of feedback. If this account of the pre-feedback thought is correct, then the passage of time might render these pre-feedback memories less accessible, perhaps resulting in a rebound of the post-identification feedback effect. A replication and extension of this design—to include a one-week retention interval—was conducted to test this hypothesis (Quinlivan et al., 2009). The results indicated that a one-week delay between the time the participants were given the prefeedback processing manipulation and the time participants answered the confidence question was sufficient to permit the feedback effect to rebound. Therefore, it appears that the feedback prophylactic is only able to inoculate against the feedback to the extent that the time between the prophylactic and the questionnaire is short. The memory traces for the identification confidence seem to deteriorate at a more rapid rate than do the memory traces for the feedback (see Quinlivan et al., 2009). The Post-Feedback Suspicion Effect Unlike the pre-feedback private thought manipulation, the post-feedback suspicion effect is the result of a manipulation that occurs after feedback. Neuschatz et al. (2007) demonstrated that making participant-witnesses suspicious about the feedback that was given by the lineup administrator leads to moderation of the post-identification feedback effect. The post-feedback suspicion method has varied somewhat across experiments, but the general idea is that a second experimenter warns the eyewitness that the first experimenter was trying to influence the results and
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that the feedback should not be treated as necessarily true. In response to the post-feedback suspicion manipulation, witnesses who had been given confirming feedback do not display the typical post-identification feedback effect. In fact, confirming feedback participants who receive the post-feedback suspicion report retrospective confidence levels similar to those who did not receive feedback. To date, there has been little theoretical examination as to why this effect occurs. The post-feedback suspicion effect is interesting because it seems to be an exception to the well-known perseverance effect demonstrated in social judgment. The perseverance effect refers to a phenomenon in which people’s beliefs persevere even after the original evidence for the beliefs has been discredited (Anderson, 1995; Anderson & Lindsay, 1998; Ross et al., 1975). We note one difference between the perseverance effect and post-feedback suspicion, which is that the perseverance effect is typically demonstrated using paradigms in which the person thinks deeply about the information prior to having the information discredited. For example, Anderson (1983) had participants think about and explain why data indicate that risky firefighters were better at their job. Other participants were instructed to think about and explain why data indicate risky firefighters were worse at their job. Even after the experimenter admitted that the data were fictitious, participants expressed beliefs in line with the view to which they had been randomly assigned. The Post-Feedback Suspicion Effect: Why Does It Occur? If feedback itself triggers an inference process, thereby creating retrospective judgments that are consistent with the feedback, then it could be argued that these newly constructed judgments ought to persist even in the presence of post-feedback suspicion. Recall however, that relevant processing is presumed to occur only when the retrospective judgments are solicited. In the original post-feedback suspicion paradigm, the relevant judgments were not solicited until after the feedback was discredited (see Experiment 1 and Experiment 2, Neuschatz et al., 2007). Therefore, it is possible that the feedback was discredited before the relevant processing associated with the feedback-effect occurred. As previously mentioned, research on the perseverance effect in social psychology typically requires participants to engage in relevant processing before the information is discredited (Anderson, 1983). One goal of the present experiment is to test the hypothesis that the post-feedback suspicion effect works because the witnesses had not yet engaged in relevant processing of the feedback prior to the feedback being discredited. Accordingly, the current design included a post-feedback thought
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manipulation: half of the participants were asked to think about the testimony-relevant judgments after receiving feedback but prior to the discrediting post-feedback suspicion (post-feedback private thought condition). A second possible reason why the post-feedback suspicion effect occurs is that the post-feedback suspicion manipulation induces a reactance-like process (Brehm, 1966). Reactance is the propensity for a person to feel an emotional response when a person or entity attempts to implement control over that person’s actions or beliefs. The core assumption of reactance theory is that people feel as if some type of freedom is being taken from them. The response that follows is one in which the person being acted upon attempts to regain that freedom by responding in ways that allow the person to regain freedom; this can include responding in ways that are in contrast with what they are being ‘‘forced’’ to do. In order to understand how this may relate to post-feedback suspicion, it is important to note that the post-feedback suspicion in prior research (Neuschatz et al., 2007) has two components. The first component is suggesting to the witness that the feedback is not necessarily correct (‘‘Were you told that you selected the correct person in the lineup? She is telling everyone that. I know for a fact…not everyone is correct.’’). The second component is the implication that there is manipulative intent—to influence the results—by the source of the feedback (e.g., ‘‘She is trying to make the DA happy’’ ‘‘They are trying to prove the accuracy of eyewitness identifications’’) and the witness is a mere pawn in this study. The reactance hypothesis would posit—in relation to the post-feedback suspicion design—that when participants are told they are being intentionally manipulated into believing that they are correct, they will react in a way that goes against those intentions. The participants may feel as if the lineup administrator is trying to make them report high confidence in order to appear accurate (i.e., prevent the participant from reporting low confidence). The participants attempt to reassert their freedom in their confidence assessment by behaving defiantly and against the intent. In other words, participants—who assume that the lineup administrator did not want them to use the low end of the scale—report that they were less certain in their identification, that they paid less attention to the scenario, and that they did not have a good view in order to thwart the manipulative intent of the person who provided the feedback. Therefore, we sought to test whether the manipulativeintent component is necessary for the post-feedback suspicion effect. We chose to remove the manipulative intent because doing so would remove any suggestion that the lineup administrator was trying to influence their behavior. To test this notion, we created two types of post-feedback suspicion conditions: one that implies a motive for the
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feedback (intent), and the other that implies the basis for the feedback was unfounded (mistake). If the post-feedback suspicion effect is the result of a reactance-type process, then the post-feedback suspicion effect should occur only in the context of a manipulative intent and not in the context of a mistake. In summary, the current research had two primary goals. The first of which was designed to test the proposition that post-feedback suspicion can occur only to the extent that the witness has not already engaged in relevant processing of the feedback. Therefore, we asked some participants to think about the relevant judgments after the feedback was administered and before the discrediting of the feedback by using post-feedback suspicion. If asking participants to process the feedback before it is discredited still leads to a post-feedback suspicion effect, then the lack of relevant processing of the feedback can be ruled out as a possible cause for the effectiveness of post-feedback suspicion. A second goal was to test whether or not the manipulativeintent component of the post-feedback suspicion was necessary for the post-feedback suspicion effect. Hence, we created two post-feedback suspicion conditions. If the mistake is as effective as the intent (in terms of feedback mitigation), then it would rule out a reactance-type interpretation of the post-feedback suspicion effect, or at least demonstrate that the assumption of manipulative intent is not necessary for the post-feedback suspicion effect.
a person on a rooftop (from about 15 feet away) placing an object down an airshaft. Only later do participants learn that the man on the roof was planting a bomb down the airshaft. The video lasts approximately 25s. The scene was shot from the first-person perspective of someone who enters an office setting, looks around at a desk, computer, and papers, and then focuses through a window. Outside the window is a roof where a man is standing at approximately 15 feet from the window. The man is a 21-year-old male with short, dark hair, medium build, and no facial hair. The man is manipulating a large object into an air shaft, looks up toward the window, appears to realize he is being watched, drops the object down the airshaft, and runs toward a rooftop door. The video then captures a view of the person coming through the rooftop door, past the camera, and then the video ends. This video was previously used by Wells, Olson, and Charman (2005).
METHOD
Questionnaire
Participants and Design
The witnessing questionnaire assessed participants’ confidence in their identification on a 7-point Likert-type scale. The questions targeted retrospective responses from the participants about testimony relevant variables such as their certainty in the selection, the amount of attention they paid to the culprit, how good of a view they had of the culprit, and their willingness to testify. These items were from the original Wells and Bradfield (1998) post-identification feedback study and have come to represent the standard items used to demonstrate the post-identification feedback effect.
Participants (N = 241) in the study were undergraduate students at a large Midwestern university who received course credit points toward their final class grade for their participation. Participants under the age of 18 were required to have parental consent. All the participants were treated according to American Psychological Association (APA) ethical guidelines. The study employed a 4 (No Feedback, Feedback Only, Feedback/Mistake, Feedback/Intent) 9 2 (No Post-Feedback Private Thought, Post-Feedback Private Thought) between-participants design. The dependent variables of interest were participants’ answers to a 14-item confidence questionnaire. Materials Video The video is a simulated crime, but it is not readily apparent that it is a crime because the participants only see
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Photo Lineup The photo lineup was displayed after the video using MediaLab software. The lineup contained six Caucasian men who resembled the person in the video; the culprit was not present in the lineup. The photographs were numbered from 1 to 6 and showed a front view of each man. Participants indicated a choice by clicking on the number that corresponded with the person they believe was in the video. This lineup was also previously used by Wells et al. (2005).
Post-Feedback Private Thought Questionnaire The post-feedback private thought questionnaire consisted of the same questions as the witnessing questionnaire, but did not include Likert scales. The Likert scale was excluded from this questionnaire to prevent participants from remembering their responses to the post-feedback private thought questionnaire, in order to avoid contaminating their response on the witnessing questionnaire. Omitting the scale would afford participants the opportunity to
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reconsider their confidence in light of the new information instead of simply remembering and repeating their original scale response. By having two different response formats— the post-feedback private thought questionnaire and witnessing questionnaire—we believe we better simulate a courtroom situation in which the response format is not always the same; thereby, causing the witness to further think about their confidence while adjusting their response to fit the question. Procedure First Experimenter After the participant arrived at the laboratory, the experimenter escorted the participant to a room where he or she was seated in front of a 17-inch computer monitor. The participant read and signed the informed consent. Afterward, the experimenter told the participant to follow the directions provided on the computer screen. When the program first started, a screen appeared that instructed the participant that the purpose of the study was to determine how well people discern personality characteristics based on seeing a person for a short time. The directions stated that the he or she would watch a video and should pay close attention to the people in the video because a memory test would be given later. After the video, a screen appeared that informed the participant that they had just witnessed a simulation of a bomb being planted on a rooftop, making him or her an eyewitness to the crime. The participant was instructed that he or she would see a lineup that contained the person from the video and the task was to identify the person from the video. All participants were given time to choose someone from the lineup. It should also be noted that the computer was angled to prevent participants in the no feedback condition from assuming that the experimenter glanced at their identification choice. When the participant was done, the experimenter either gave no feedback about the choice, or gave confirming feedback ‘‘Good you selected the actual person from the video.’’ Afterward, all the participants were told that because we only had the program on one computer, and had lots of students to be signed up in the experiment, the participant would go with a second experimenter and finish the experiment in another room. Second Experimenter As with the first part of the experiment, all of the participants in the second half of the study were randomly assigned to conditions. The second experimenter escorted all of the participants to another room: some participants reviewed the set of 14 post-feedback private thought
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questions for 5 min, and others sat quietly for 5 min. The experimenter returned after 5 min. Those who had received feedback were randomly assigned to one of two postfeedback suspicion conditions or the no post-feedback suspicion condition. The two types of post-feedback suspicion were: Mistake. ‘‘Ok, before we begin, I would just like to ask you a few questions ok? Did he/she tell you that you picked the correct person? We are just asking because in our pilot study for this experiment, we originally had the lineup set up so that if you selected the correct person, your picture would be highlighted and then it would show your number in the top corner. Well, we have recently changed that and so now the computer just highlights your choice and then shows the number in the corner to indicate that was the person you chose. In fact, he/ she has no way of knowing if you picked the correct person. We are going to have to tell her to stop doing that. So you cannot assume that you chose the right person or not based on what was said.’’ Intent. ‘‘Ok, before we begin, I would just like to ask you a few questions ok? Did he/she tell you that you picked the correct person? We are just asking because in our pilot study for this experiment, we originally had the lineup set up so that if you selected the correct person, your picture would be highlighted and then it would show your number in the top corner. Well, we have recently changed that and so now the computer just highlights your choice and then shows the number in the corner to indicate that was the person you chose. In fact, he/she has no way of knowing if you picked the correct person. She knows that we changed to this new program. She is just trying to influence the results. We are going to have to tell her to stop doing that. So you cannot assume that you chose the right person or not based on what was said.’’ Subsequently, all the participants answered a 14-item confidence questionnaire to assess the general eyewitness identification experience. Thereafter, a manipulation check was performed using two open-ended questions. The first question asked if an experimenter indicated that they made a correct identification; the second question asked if an experimenter indicated that some information they were given might not have been true. Finally, the participants were fully debriefed about the purpose of the experiment, including the need to not tell them beforehand that the lineup did not contain the bomber on the roof and the purpose of the feedback and post-feedback suspicion.
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RESULTS Overview The current research had two primary goals. First, we wanted to test the proposition that the post-feedback suspicion effect can occur only to the extent that the witness has not already engaged in relevant processing of the feedback. Our results did not support that proposition. Second, we wanted to examine whether or not the manipulative-intent component of the post-feedback suspicion was necessary to reduce the post-identification feedback effect. Our results showed that manipulative intent was not necessary for the post-feedback suspicion manipulation to be an effective moderator of the postidentification feedback effect. We report effect sizes using the effect size statistic d (small effect = .20, medium effect = .50, large effect = .80) for all the single degreeof-freedom tests.
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raters categorized statements as Mistake, Intent, or Other using a reference sheet to assist them in the types of indicators they should look for in the statements (e.g., Mistake—accident, did not know, confused). Both raters were instructed to categorize any ambiguous statements as Other (i.e., the statement did not indicate Mistake or Intent). Raters agreed 90% of the time and a Cohen’s Kappa (3 9 3) of .816 was obtained. Participants’ openended responses from the Intent condition were categorized by both raters as belonging in the Intent category for 14 out of 15 participants. Participants’ open-ended responses from the Mistake condition were categorized by both raters as belonging in the Mistake category for 12 out of 15 participants. There were no instances in which a participant’s statement from the Mistake condition was placed in the Intent category by either rater or vice versa. Hence, we believe that the Intent and Mistake manipulations were successfully manipulated. Retrospective Certainty
Manipulation Checks All of the participants who received Feedback correctly reported receiving feedback. Likewise, all the participants in the No-feedback condition responded that they did not receive feedback on the identification. In addition, all but two of the participants in the Post-feedback Suspicion condition were able to correctly report the post-feedback suspicion. These two participants were excluded from all analyses. It is clear that the rest of the participants were attending to both manipulations. After we had completed the initial study, we noticed that the manipulation check that we used was not adequate for the manipulation. At first, we tested whether participants noticed the discrediting-of-feedback manipulation, but did not test whether participants noticed that there was intent by the experimenter to influence the participant in one condition whereas there was a mere mistake made in the other condition. A reviewer raised the possibility that the participants were interpreting both the Mistake and Intent manipulations as Intent. In general, we wanted to find out whether participants actually noticed the difference in these two methods of discrediting the feedback. In order to test this, an additional 30 participants were randomly assigned to the feedback/intent condition or the feedback/mistake condition. The experimental procedure was identical to the original study except that a new manipulation check question was added after collection of the dependent measures. Specifically, these participants were asked the open-ended question, ‘‘Why do you think the first experimenter told you that you were correct?’’ Two independent raters, who were blind to both the purpose of the study and to the conditions, rated each open-ended response. Both
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Given the centrality of retrospective certainty in the eyewitness literature and its apparent impact on jurors, a separate analysis was conducted on the certainty measure. A 4 (No Feedback, Feedback-only, Feedback/Mistake, Feedback/Intent) 9 2 (No Post-Feedback Private Thought, Post-Feedback Private Thought) ANOVA was conducted to assess the effects of feedback and post-feedback private thought on retrospective judgments of certainty. All the participants made an identification and were included in the analysis. Did the post-feedback private thought manipulation mitigate the results? No. The results revealed a main effect of Feedback, F(3, 233) = 16.87, p \ .0001, but there was no significant main effect for Post-feedback Private Thought, F(1, 233) = .09, p = .768, d = .04, and there was no significant interaction between Feedback and Post-Feedback Private Thought, F(3, 233) = .63, p = .597 (see, Table 1 for the means and standard deviations in all feedback conditions). Planned pair-wise comparisons were conducted to further explore the main effect of the four feedback conditions. The first contrast revealed that feedback-only participants were more likely to report increased retrospective certainty (M = 5.2) compared to those who did not receive feedback (M = 3.6), F(1, 233) = 47.37, p \ .0001, d = 1.34., which replicates previous post-identification feedback studies (Wells & Bradfield, 1998). However, when feedback participants were given information that suggested that the experimenter made a mistake (Mistake), or intentionally deceived them (Intent), there was a significant reduction in the retrospective certainty relative to participants who only received feedback F(1, 233) = 23.59, p \ .001, d = -.98, and F(1, 233) = 10.72, p \ .01, d = .60 (for the Mistake
Law Hum Behav (2010) 34:186–197 Table 1 Means and standard deviations for retrospective confidence reports
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No feedback (N = 62)
Feedback only (N = 62)
Mistake (N = 60)
Intent (N = 57)
M
SD
M
SD
M
SD
M
SD
Certainty
3.6
1.3
5.2
1.0
4.0
1.2
4.4
1.4
View
3.6
1.1
4.6
1.4
4.4
1.3
4.4
1.4
Feature
3.1
1.1
4.3
1.4
3.7
1.3
4.0
1.4
Distance
3.9
1.2
4.2
1.0
4.4
1.0
4.1
1.5
Attention
3.6
1.6
4.1
1.5
3.9
1.4
3.8
1.5
Basis
3.9
1.2
2.4
1.3
3.2
1.3
3.1
1.4
Easy
4.8
1.4
3.2
1.3
4.5
1.3
4.1
1.6
How Long
4.3
1.4
2.8
1.2
3.8
1.4
3.7
1.4
Testify
2.3
1.3
4.5
1.5
2.8
1.4
3.3
1.7
Trusted
3.0
1.3
4.5
1.5
3.7
1.4
4.1
1.5
Faces Sure
3.8 3.5
1.8 1.4
5.2 5.0
1.3 1.1
4.7 4.0
1.3 1.4
4.8 4.1
1.5 1.5
See
3.7
1.3
4.7
1.2
4.2
1.3
4.4
1.4
Image
3.3
1.3
4.5
1.2
3.7
1.3
4.0
1.5
and Intent conditions, respectively. The findings are consistent with Neuschatz et al. (2007) and underscore the effectiveness of suspicion as a remedy for post identification feedback. The differences between the retrospective certainty reports for those in the Mistake condition (M = 4.0) compared to those in the Intent condition (M = 4.4) were not significant, F(1, 233) = 2.28, p = .13, d = .27. One explanation for the results is that there was not enough power to detect significant differences between the Intent and Mistake conditions. A power analysis (with G*Power 3.0, Faul, Erdfelder, Lang, & Buchner, 2007) was conducted using half the effect size of the feedback effect that was found in a recent meta-analysis, d = .40 (Douglass & Steblay, 2006). The power analysis was conducted assuming a one-tailed t-test and p \ .05. The results revealed there was enough power (greater than 80%) to detect half the usual effect size of the post-identification feedback effect. Still, we do not conclude that the Mistake and Intent manipulations had equal effects and, in fact, as reported in the next section on the other measures, using a MANOVA it appears that the Mistake manipulation was actually more effective than the Intent manipulation in minimizing the post-identification feedback effect. Other Retrospective Judgments The results of all of the remaining questions were combined using a MANOVA. When the remaining measures were all combined, a difference between the Mistake and Intent conditions emerged. A 4 (No Feedback, Feedback Only, Feedback/Mistake Feedback/Intent) x 2 (No PostFeedback Private Thought, Post-Feedback Private Thought) MANOVA was conducted on the remaining 13
questions. All the participants chose and were included in the analysis. The results revealed a main effect for Feedback, F(39, 665.2) = 3.20, p \ .001. Neither the main effect for Post-Feedback Private Thought, F(13, 221) = 1.703, p = .06 nor the interaction between Feedback and Post Feedback Private Thought, F(39, 665.2) = 1.02, p = .425 was significant. These results are consistent with the omnibus ANOVA reported above on retrospective certainty. As was the case for retrospective certainty, planned comparisons were conducted on the Feedback condition for the remaining 13 variables. When participants received feedback only, they were more likely to inflate their retrospective self-reports compared to those who did not receive feedback, F(13, 221) = 7.27, p \ .0001, again, replicating the effects of post-identification feedback previously demonstrated (Wells & Bradfield, 1998). Both the Intent F(13, 221) = 2.24, p = .009 and Mistake conditions F(13, 221) = 4.76, p \ .0001 significantly reduced the effects of the feedback. An analysis comparing responses in the Intent and Mistake demonstrates significant differences, F(13, 221) = 2.14, p = .013. Thus, it appears that, although both mistake and intent can reduce the effect of confirming post identification feedback, the mistake manipulation—when combining all 13 remaining variables—was more effective than the intent manipulation.
DISCUSSION There were two major purposes of the current research. First, we wanted to examine whether post-feedback private thought would lead to feedback facilitation that would then prevent the post-feedback suspicion effect. Second, we
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wanted to examine whether the manipulative-intent component of the post-feedback suspicion is necessary for the post-feedback suspicion effect. Our results indicate that the post-feedback private thought manipulation did not mitigate the post-feedback suspicion effect. Therefore, it seems that the relevant-processing hypothesis for the post-feedback suspicion effect can be ruled out. In addition, the perception of manipulative intent by the source of the feedback is not necessary for post-feedback suspicion; in fact, our mistake condition was somewhat more effective than the intent condition in mitigating the effects of feedback. Accordingly, we do not think that the post-feedback suspicion effect is the result of a reactance-like process. We considered the possibility that successful postfeedback suspicion would be restricted to conditions that did not allow relevant processing of the feedback. Previous studies using the post-feedback suspicion had not primed relevant processing of the feedback (e.g., thoughts about retrospective certainty) prior to discrediting the feedback. The results however, indicate that relevant processing following feedback did not mitigate the post-feedback suspicion effect. The absence of a significant effect for the post-feedback private thought manipulation is interesting in light of significant moderating effects of this same manipulation when this manipulation occurs prior to feedback (Neuschatz et al., 2007; Quinlivan et al., 2009; Wells & Bradfield, 1999). When it occurs prior to feedback, manipulation of private thought (about certainty, view, and so on) serves a prophylactic function of preventing feedback from having an impact on witness’s retrospective judgments. The theory is that pre-feedback private thought creates a memory trace that witnesses rely on later when they have to make judgments about their retrospective certainty. Hence, we expected that post-feedback private thought would also promote a memory trace, in this case one that was biased by the feedback, and that this would persist even after the feedback was discredited. We now suspect that one important difference between the two situations is that the pre-feedback thought promotes memory traces for internal information (e.g., fluency, ease of identification, feelings of confidence) whereas post-feedback thought promotes memory traces for external information (specifically, the feedback). Because the external feedback information is already well remembered and highly accessible (easily recalled at least one week later, Quinlivan et al., 2009), the post-feedback processing has no additional effect. We were initially surprised that the post-feedback thought manipulation did not hinder the mitigating effects of post-feedback suspicion because belief-perseverance effect studies consistently report that discredited information tends to persevere after the information has already been processed. Looking back at the belief-perseverance
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literature, however, we now realize that these studies generally do not compare the discrediting condition back to a no-discrediting condition and, when they do, it is clear that the discrediting manipulation has a significant effect. But the belief-perseverance literature is not generally interested in the question of whether the discrediting manipulation has an effect; the interest is that the effect of discrediting is not full or complete. Hence, the belief-perseverance effect appears to be a ‘‘partial perseverance’’, but not total perseverance. That is the same as what we found in the current experiment; the post-feedback suspicion manipulations partially eliminated the feedback effect, but did not fully eliminate the feedback effect. Hence, we do not necessarily see any inconsistency between the current results and those found in the belief-perseverance literature. Secondly, we were surprised that the discrediting manipulations were effective because the feedback could be construed as an anchor that should have hampered adjustment. The anchoring-and-adjustment literature shows that a ‘‘starting point’’ on some judgment tends to anchor the judgment in the sense that later adjustments from that starting point (based on further considerations) tend to be insufficient (Fiedler, 1999; Fiske & Taylor, 1991; Tversky & Kahneman, 1974). Again, however, we note that the certainty means for the Mistake and Intent conditions are actually higher than the control (no-feedback) condition, suggesting that perhaps their adjustments were in fact ‘‘insufficient.’’ Indeed, the current findings are consistent with the idea that there was some anchoring from the feedback and that adjustments from that anchor based on the suspicion manipulations were insufficient. Although there were no significant differences in certainty between the mistake and intent conditions, both conditions showed significant mitigation of the post-identification feedback effect. We note, for example, that retrospective certainty in the intent condition remained significantly higher than the control condition whereas the intent condition did not significantly differ from the control condition. Furthermore, the MANOVA on the remaining 13 variables produced a significant difference between the Mistake and Intent conditions in which the mistake conditions were more effective. Why would the mistake manipulation be more effective than the intent manipulation, especially given that both have the mistake component (both say, ‘‘In fact, he or she has no way of knowing if you picked the correct person’’). One possibility is that some subset of participants in the Intent condition had a compliant response (rather than a reactance response) to the first experimenter’s intent, and hence, did not adjust their responses downward. For the purposes of this study, however, it does not matter because our main point is that the mistake manipulation worked; hence, manipulative
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intent is not necessary to obtain post-feedback moderation of the post-identification feedback effect. The Concept of Continual Malleability We believe that the results seem to be more consistent with what we will call continual malleability. We posit that these retrospective judgments might never fully solidify and instead remain malleable as a function of new information. This is not to say that public pronouncements of these judgments, such as stating on paper or orally to other people ‘‘I had a great view and I am positive’’ would remain malleable. Clearly, there are well-established commitment effects from making public statements owing to a variety of forces such as dissonance, the need to appear consistent to other people, and so on (Festinger, 1954; Festinger, 1957; Festinger & Carlsmith, 1959). But the continual-malleability hypothesis states that, in the absence of commitment effects, the underlying judgments remain fluid and adaptable to new information. The accessibility-inferences conceptualization has been widely endorsed by post-identification feedback researchers (e.g., Bradfield et al., 2002; Dixon & Memon, 2005; Douglass & McQuiston-Surrett, 2006; Hafstad, Memon, & Logie, 2004; Neuschatz et al., 2005, 2007; Semmler & Brewer, 2006; Semmler et al., 2004; Skagerberg, 2007; Wells & Bradfield, 1998, 1999; Wells et al., 2003; Wright & Skagerberg, 2007; see, meta-analysis by Douglass & Steblay, 2006). How can the current results be reconciled with the accessibility-inferences conceptualization? We believe that the current results and the continual-malleability hypothesis do not change the fundamental assumptions underlying the accessibility-inference conceptualization of the post-identification feedback effect. Instead, the continuing-malleability observation expands our understanding of the accessibility-inference conceptualization by noting that these inferences do not readily solidify and that new information can lead people to recalculate their inferences with little in the way of residual effects of prior inferences. Despite the fact that the continuing-malleability hypothesis is easily merged with the accessibility-inferences conceptualization, an interesting conundrum nevertheless presents itself. If witnesses have little or no cognitive trace for their pre-feedback judgments, how do they manage to ‘‘roll back’’ these judgments to values that are close to the control (no feedback) condition when the feedback is discredited? Recent research by Charman and Wells (2008) suggests an answer. Using a ‘‘counterfactual estimation’’ paradigm, Charman and Wells found that mere hypothetical thinking (‘‘How would you have answered these questions if you had never received feedback?’’) can account for how witnesses ‘‘removed’’ the effect of post-
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identification feedback when it was discredited. This idea is consistent with the Flexible Corrections Model (Wegener & Petty, 1997) that is used to account for how people can correct for biases without having any introspective access to their unbiased judgments. In effect, these corrections represent people’s guesses (albeit thoughtful guesses or what Wegener and Petty called implicit theories) about how an event is likely to have influenced them. Given this flexible-corrections process, witnesses do not have to have access to their pre-feedback judgments in order to remove the effects of the feedback manipulation when the feedback is discredited. Additional research on the issue of continual malleability could prove to be very important for both practical and theoretical reasons. From a practical or applied perspective, these retrospective judgments (especially certainty, view, and attention) are central to courts’ determination of the reliability of the identification (Manson v. Braithwaite, 1977). Accordingly, it would be important to know when, if ever, in the investigative or judicial process the witnesses’ retrospective judgments are calcified and no longer fluctuating in response to external events. After all, external events can unfold months later at preliminary hearings or even in early parts of the trial that could drive witnesses’ beliefs regarding the guilt of the defendant and hence, malleate these retrospective judgments. Final Remarks The current study replicated the robust effect of postidentification feedback on eyewitness confidence. Although the reported effect size d of 1.34 helps communicate the large magnitude of the post-identification feedback effect, we think it is useful to also express the effect in a forensically relevant manner that might give readers a better intuitive grasp of the strength of the postidentification feedback effect. Hence, we created Fig. 1, which shows the calculated percentages of participants who reported a certainty score of 6 or 7 (on the seven-point certainty scale) for each condition. This is important because it is very certain, albeit mistaken, witnesses who would most likely make it to the trial to testify. As shown in Fig. 1, among participants who were not given any feedback, not a single participant reported a certainty level above 5. However, feedback-only participants reported a high certainty level—6 or 7—40% of the time. And, it is important to keep in mind that the certainty measure is not the participants’ current certainty, but instead their retrospective certainty; i.e., reports of how certain they recall having been at the time they made their identification. This robust effect should be of great concern for the legal system because it transforms mistaken eyewitnesses who otherwise were uncertain (and hence, not likely to lead to
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196 50 40 30 20 10 0
one two three four five six seven one two three four five six seven one two three four five six seven one two three four five six seven
Percentage of Participants
Fig. 1 Percentages of participants at each level of confidence (1 = low confidence, 7 = high confidence) by condition
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No feedback
Feedback only
Feedback/Mistake
Feedback/Intent
Confidence Level and Condition
charges against the innocent person) into certain witnesses who would likely end up testifying against the innocent person. It is also important to note that post-identification feedback cannot always be discredited in actual cases. In fact, it would be an unusual circumstance in which discrediting post-identification feedback would be possible in real-world cases. The problem with post-identification feedback in real-world cases is not necessarily that the feedback is unreliable. For instance, telling an eyewitness that the identified person was also identified by another witness or that the identified person was found in possession of the stolen goods may very well be truthful information. The problem with post-identification feedback is that it contaminates what the eyewitnesses’ subsequent responses to the Manson reliability test criteria (Manson v. Braithwaite, 1977): later claims about how much attention the eyewitness paid to the culprit, how good the eyewitness’s view, and how certain the eyewitness was at the time of the identification. Clearly, these judgments should be based on the eyewitness’ independent recollections rather than on comments—regardless of the reliability—concurrent with or following the lineup. It is useful to know that the post-identification feedback effect can be mitigated if the feedback is somehow discredited, but the best solution to the post-identification feedback problem is prevention rather than correction. Psychological science has articulated a simple prevention solution, namely, the double-blind lineup procedure followed immediately by having a blind lineup administrator secure a certainty statement from the witness (Wells, 1988, 1993; Wells & Luus, 1990; Wells et al., 1998). With the double-blind procedure, the lineup administrator does not know whether the witness picked a filler or picked the suspect and hence, cannot reinforce the witness’s choice. A
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record can then be made of the witness’s certainty (as well as statements about view, attention, and so on) before there is any opportunity for the witness to receive feedback. Although this would not prevent the witness from getting feedback from other sources, the witness’s earlier (uninfluenced) answers would be discoverable at pre-trial hearings and at trial. Acknowledgments The authors would like to thank Miko M. Wilford and Samantha J. Tuhn for editing the early version of the article. In addition, the authors extend gratitude to Brandon Butcher, Devin Harker, Melissa Knight, Lindsey Upton, Miranda Wilkinson, and Sara Forte for running the participants in the study.
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