The illusion of the perfect alibi: Establishing the base rate of non‐offenders' alibis

The present study was designed to establish the base rate of alibis and supportive evidence for alibis of non‐offenders. That is important because the presence and lack of an alibi are often seen as a clear indicator of innocence and guilt, respectively, of a suspect. A large sample of laypersons (N  = 841) was randomly assigned to one of 32 conditions in which they were asked to generate a true alibi after they were falsely accused of being the perpetrator of a mock robbery. Each condition consisted of either a Tuesday or a Saturday and one of 16 timeframes. In general, the majority of the participants had an alibi (99.5%) and supportive evidence for their alibis (92.4%). The supportive evidence often consisted of a combination of supportive evidence rather than one distinct form of supportive evidence (33.3%). Although it is widely assumed that the alibi believability is determined based on the strength of the supportive evidence, our results show that the type of evidence that can be presented by laypeople depends upon the day and the timeframe wherein the crime has been committed. The results of the study therefore imply that determining alibi believability solely on the strength of the supportive evidence is not a fair measure. We suggest that the believability should also be based on the base rate of alibis and its supportive evidence.     

“I think you did it!”: Examining the effect of presuming guilt on the verbal output of innocent suspects during brief interviews

Innocent suspects interviewed by a guilt‐presumptive versus innocence‐presumptive or neutral interviewer may tend more to display non‐verbal behaviours which neutral judges consider indicative of guilt. We examined the effects of interviewer's presumption of guilt on innocent mock suspects' alibis. Participants (N = 90) provided an alibi to convince an interviewer of their innocence of a theft after she implied that she believed that they were guilty or innocent or that she had no belief about their veracity. On the basis of existing conflicting findings for suspects' verbal behaviour during accusatory interviews, we predicted that alibis in the guilt‐belief condition would contain the highest or lowest number of correct details with overall higher or poorer accuracy rates, respectively. Although participants perceived the interviewer's presumptive approach, the number of correct details provided and accuracy rates of alibis did not differ significantly between conditions. We propose explanations to these findings and future research paths.     

Race and information processing in criminal trials: does the defendant's race affect how the facts are evaluated?

Two studies examined whether a criminal defendant's race influences Whites' sensitivity to legally relevant information. In Study 1, prosecution case strength ratings and guilt likelihood ratings were more sensitive to the strength of the defendant's alibi when he was Black than when he was White, if the experimental task was designed to elicit low processing motivation. Under high motivation, participants were equally sensitive to alibi strength, regardless of defendant race. In Study 2, the alibi strength manipulation was replaced with a manipulation of the effectiveness of the district attorney's cross-examination. As predicted, defense case strength ratings were more sensitive to the strength of the prosecutor's cross-examination with a Black defendant than with a White defendant-under low motivation. Under high motivation, sensitivity did not depend on defendant race. These results suggest that a Black defendant can elicit greater sensitivity to legally relevant information than will a White defendant.     

Alibi believability: Corroborator certainty,cooperativeness and relationship with the defendant

Alibi believability can be affected by characteristics of the alibi corroborator, including the relationship between the defendant and corroborator, which has been studied extensively by researchers. The corroborator's certainty that they were together at the time of the crime may also influence alibi believability, but only a few studies have examined this. Another factor that may affect believability is the corroborator's cooperativeness with the police, which is yet to be studied in the alibi context. Online U.S. participants recruited from CloudResearch (N = 280) acted as mock jurors and evaluated a mock arson case where the defendant used an alibi defence. The alibi corroborator's relationship to the defendant (brother/neighbour), the certainty that they were together at the time (65%/100%) and cooperativeness with police (cooperative/uncooperative) were manipulated between participants. The participants were evenly split when it came to verdict (p > .05) but were more likely to vote guilty when the corroborator was a brother rather than a neighbour (p < .01) and when the brother was uncooperative versus cooperative (p < .05). As expected, alibis were more believable when they were corroborated by a neighbour rather than a brother and when the corroborator was 100% certain that they were together versus 65% certain (ps < .01). Alibis were also more believable when the corroborator cooperated than when he was uncooperative (p < .01). Cooperative (vs. uncooperative) corroborators led to more positive defendant and corroborator views on all six character trait measures (ps < .01). Implications and future directions are discussed.     

Evidence Evaluation and Evidence Integration in Legal Decision‐Making: Order of Evidence Presentation as a Moderator of Context Effects

Legal decision‐making studies often demonstrate context effects: People's initial beliefs about a suspect's guilt influence their evaluation of subsequent evidence. We examine three potential moderators of these context effects: Order of evidence presentation, ability to ruminate, and valence of the initial belief (innocence or guilt). College students (n = 382) were presented with DNA evidence (incriminating or exonerating) and an ambiguous alibi in one of two orders (or just the alibi), and then evaluated how strongly the alibi incriminated the suspect and the suspect's likelihood of guilt. Results indicated that alibi evaluation exhibited context effects when (i) initial beliefs were of guilt (but not of innocence) and when (ii) evaluating subsequent evidence (but not when retroactively evaluating prior evidence). Rumination failed to moderate any effects. The integration of evidence exhibited recency effects: DNA had a greater impact on participants' beliefs in the suspect's guilt when presented last rather than first. Copyright © 2015 John Wiley & Sons, Ltd.     

“He Couldn't Have Done It,He Was With Me!”: The Impact of Alibi Witness Age and Relationship

Undergraduate participants who conducted a simulated police investigation were presented with either a child (6 years old) or adult (25 years old) alibi witness, who was either the son or neighbor of the participant's suspect. Replicating previous research, participants were more likely to believe the adult neighbor alibi witness than the adult son. In fact, an alibi provided by the adult son actually proved detrimental to that suspect, as participants thought the suspect was more likely to be guilty after viewing an alibi provided by the adult son. However, child‐provided alibis reduced perceptions of suspect guilt, regardless of that child's relationship to the suspect. The child alibi witnesses were also viewed by the participants as more credible than the adult witnesses. Copyright © 2011 John Wiley & Sons, Ltd.     

Juror Underutilization of Eyewitness Nonidentifications: A Test of the Disconfirmed Expectancy Explanation1

The impact of two types of eyewitness testimony on mock jurors' judgments was explored. A crime eyewitness either testified that the defendant definitely was the robber (identification), definitely was not the robber (nonidentification), or that they weren't sure if he was or was not the robber (control). An alibi eyewitness testified that the defendant either definitely was at the alibi location (identification), definitely was not at the alibi location (nonidentification), or he wasn't sure if the defendant was or was not at the alibi location (control). Strength of case was also manipulated. Results show that crime eyewitness identifications and alibi eyewitness nonidentifications were underutilized. A crime eyewitness by alibi eyewitness interaction revealed that within the crime eyewitness identification condition alibi identification was underutilized whereas with the other two crime eyewitness conditions, alibi nonidentification information was underutilized. The results supported a disconfirmed expectancy explanation.     

Improving Juror Comprehension of Judicial Instructions on the Entrapment Defense1

When the defense of entrapment is raised, the legal and psychological question is not whether the defendant committed some illegal act, but rather why the defendant behaved as he or she did and whether government agents' actions provoked the defendant to commit the same crime. The subjective test of entrapment focuses on the predisposition of the defendant to commit a particular crime, while the objective test focuses on situational forces. In Study 1, type of entrapment defense (subjective, objective) and the defendant's prior record (no prior record, prior record) were experimentally manipulated. As expected, superior comprehension of the judge's instructions was found for jurors who heard subjective test instructions. Study 2 was designed to improve the comprehension and judgments of jurors who received 1 of 3 versions of the objective test. Juror comprehension of key legal concepts and subsequent judgments improved if jurors heard one of the rewritten versions of the objective test.     

Safety in Numbers: A Policy‐Capturing Study of the Alibi Assessment Process

A policy‐capturing analysis of alibi assessments was conducted. University students (N = 65), law enforcement students (N = 21), and police officers (N = 11) were provided with 32 statements from individuals supporting a suspect's alibi (i.e., alibi corroborators) and asked to assess the believability of the alibi, the suspect's guilt, and whether they would arrest the suspect. Each statement was composed of five binary features (i.e., relationship between corroborator and accused, age of corroborator, amount of available corroborators, alibi corroborator's confidence in their account, and memorability of the target event). Results showed that there was much parity in the type of information used to assess alibis across the samples. Specifically, we found that 90% of participants' decision policies included the amount of corroborators. Participants also relied upon, albeit to a lesser extent, the suspect–corroborator relationship and the age of the corroborator when assessing the alibi. The potential implications of these findings for understanding how people assess alibi corroborators are discussed. Copyright © 2016 John Wiley & Sons, Ltd.     

Deceiving suspects about their alibi is equally harmful to the innocent and guilty

A common belief in police officers is that guilty suspects' statements are less consistent than innocent suspects'. This could leave guilty suspects more vulnerable to missing inconsistencies externally induced into their alibis. Source monitoring and cognitive load approaches suggest that untruthfulness rather than guilt should predict proneness to such deception. Manipulating both guilt and truthfulness, we tested these opposing hypotheses. One hundred twenty‐six participants were accused of stealing gift vouchers after wandering about a building. When interviewed several days later, participants rarely detected alterations in their alibi (23–29%). Unexpectedly, for one of three detection measures, untruthful participants detected more manipulations than did truthful participants. Guilt did not moderate detection rates. Manipulations were equally harmful for guilty and innocent suspects, and blindness to the alibi manipulations was not useful for discriminating innocent from guilty suspects. Because blindness effects are easy to elicit in the legal context, techniques that externally induce inconsistencies should be avoided.     

“You don't expect me to believe that,do you?” Expectations influence recall and belief of alibi information

Presumptions of guilt could bias criminal investigators' interviews of suspects, reducing recall of exculpatory alibi information, and the label “alibi” could be enough to create a presumption of guilt. Participants (n = 285) viewed a videotaped narrative account; some participants knew prior to viewing that the account was an alibi whereas others discovered this after viewing. Also, some participants were given an expectation that the alibi provider was guilty or innocent. Results indicated participants with a presumption of guilt before viewing the alibi recalled less alibi‐relevant information, found the alibi less believable, and viewed the alibi provider more negatively than did participants without such an expectation, and that a label of “alibi” was not enough to create a presumption of guilt.     

Biases In Trials Involving Defendants Charged With Multiple Offenses1

Under federal and state laws, a defendant who has been charged with more than one offense can be tried for all the offenses in a single “joined” trial. It was predicted that the probabillty a defendant would be convicted would increase as a function of the number of joined offenses. Legal theories, research on memory, and social psychological models of information integration and attribution led to three hypotheses as to why this bias might occur: (1) confusion of evidence, (2) accumulation of evidence, and (3) inference of a criminal disposition. Subjects read and judged written trial summaries presented as joined or single trials. In Study 1, joinder resulted in higher rates of conviction and in confusion of evidence. In Study 2, the conviction results were replicated, and subjects judging joined trials also rated the evidence as more incriminating and made negative attributions about the defendant. These ratings were strongly related to judgments of guilt. A sequential judgment process was also found to affect jurors' judgments.     

Prejudicial Joinder of Multiple Offenses: Relative Effects of Cognitive Processing and Criminal Schema

The relative contributions of cognitive processing of evidence and invocation of a criminal schema to the effects of joinder of offenses was investigated. One hundred forty simulated jurors either judged no evidence or judged evidence from one or two charges with the knowledge that the defendant had been charged with either one, two, three, or four offenses. The results showed that guilt evaluations, defendant character ratings, and measures of memory were influenced more by the number of charges judged than by the number of charges filed. Results from two path analyses suggest that the joinder effect is mediated by both cognitive factors and judgments about the defendant's character. Joinder appears to affect the cognitions generated about the cases, which in turn affect perceptions of the defendant and ultimately guilt assessment.     

Another Look at the Impact of Juror Sentiments toward Defendants on Juridic Decisions

Abstract

This experiment tested the hypothesis that jurors' preexisting biases (sentiments) toward an accused would have a much stronger impact on the sentences that jurors recommended than on the verdicts they rendered. Specifically, a balance theory analysis of juridic decisions specifies that predeliberation sentiments toward the defendant would have little if any direct effect on jury verdicts and would be associated with verdicts rendered only if the information establishing these sentiments also implied a unit relation between the defendant and the crime. Six-person juries deliberated the case of an accused robber and murderer who had no prior criminal record, a prior conviction for a dissimilar crime, or a prior conviction for a similar crime. While on the witness stand, the defendant either withheld information or provided answers for all questions. The results provided strong support for the hypothesis. In addition, jurors' predeliberation sentiments toward the accused were unrelated either to the tone of juridic deliberations or to postdeliberation assessments of the defendant's guilt. By contrast, juror sentiments toward the defendant were a solid predictor of the severity of sentences assigned by those who voted to convict the accused.     

How jurors use and misuse character evidence

The Federal Rules of Evidence allow defendants to offer testimony about their good character, but that testimony can be impeached with cross-examination or a rebuttal witness. It is assumed that jurors use the defense's character evidence (CE) to form guilt and conviction judgments but use impeachment evidence only to assess the character witness's credibility. Two experiments tested these assumptions by presenting mock jurors with various forms of CE and impeachment. Participants made trait ratings for the character witness and defendant and guilt and conviction judgments. Positive CE did not affect guilt or conviction judgments, but cross-examination caused a backlash in which judgments were harsher than when no CE was given. Using path analysis, the authors tested a model of the process by which CE and impeachment affect defendant and witness impressions and guilt and conviction judgments. Implications for juror decision making are discussed.     

Of private talk and public print: General pre-trial publicity and juror decision-making

The term ‘general pre-trial publicity’ refers to trial-related information that is prominently in the news, and that affects jurors in wholly unrelated cases. Two experiments explored the impact of general pre-trial publicity on juror decision-making. In Experiment 1 mock jurors who earlier read a newspaper article about a defendant mistakenly identified and subsequently convicted of a crime he did not commit were less likely to convict the defendant in an unrelated case than were jurors who read instead about a series of heinous crimes or who had no pre-trial publicity. Experiment 2 demonstrated that this effect is somewhat stronger when the general pre-trial publicity concerns a case that closely resembles the one jurors must decide than when the two cases are dissimilar. These data are discussed in terms of the availability of relevant information in memory. People may evaluate the probability of a defendant's guilt by the ease with which similar or relevant examples come to mind.     

Motivational sources of confirmation bias in criminal investigations: the need for cognitive closure

In two experiments, criminal investigators (N = 50) and undergraduate students (N = 68) read a set of facts from the preliminary investigation of a homicide case. Participants' initial hypothesis regarding the crime was manipulated by providing background information implying that the prime suspect had a jealousy motive or that there might be an alternative perpetrator. Students displayed a framing effect, such that guilt was ascribed to the prime suspect only when a potential motive was presented, whereas investigators did so regardless of hypothesis, thus being less sensitive to alternative interpretations. Investigators' need for cognitive closure (NFC) moderated the effect of the hypothesis on perceptions of the strength of the evidence against the prime suspect; high (v low) NFC investigators were less likely to acknowledge inconsistencies in the material when presented with a potential motive, but were more likely to do so when made aware of the possibility of an alternative perpetrator. Interpretations are somewhat clouded by the fact that dispositional NFC did not seem to affect in a consistent manner participants' motivation toward the experimental task. Copyright © 2005 John Wiley & Sons, Ltd.