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.     

Information Processing in Joined and Severed Trials

The present study was conducted to determine the process by which jurors reach verdicts in trials in which multiple charges are joined in one indictment. The experiment was designed to test the impact of joinder of affenses, similarity of offenses, and evidentiary strength of jurors' ability to process trial evidence. The results gathered from 220 male and female subjects indicated, as previous research has shown, that joined trials lead to more guilty verdicts than severed trials; that the first charge in a joined trial accounts for this "joinder effect," receiving significantly more guilty verdicts than its severed counterpart. When joined trials are composed of similar categories of crimes, guilt verdicts increase and jurors tend to confuse evidence-as shown by a high rate of antidefendant intrusions from case two to case one. More antidefendant cognitions were also found when the cases were similar. Furthermore, case similarity interacted with the evidentiary strength of the charges in joined trials.     

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.     

Perceptions of Children's Credibility in Sexual Assault Cases1

Children's testimony often plays a central role in prosecutions of child sexual abuse. Nevertheless, research on jurors' perceptions of the credibility of child sexual assault victims remains limited. In three experiments, we examined mock jurors' reactions to children's testimony about sexual abuse. Participant jurors were exposed to videotaped or written scenarios of child sexual abuse trials and then rated victim credibility and defendant guilt. Analyses indicated that: (a) victim age was either inversely related or unrelated to perceptions of victim credibility, (b) women were more likely than men to find child victims credible, (c) corroborating testimony from a child victim increased the credibility of another child victim, and (d) exposure of participants to past criminal acts and other negative defendant character evidence heightened perceived victim credibility and defendant guilt. Implications for understanding jurors' reactions to child witnesses are discussed.     

The Consideration of Rape: The Effect of Target Information Disparity on Judgments of Guilt1

We hypothesized that increasing the amount of individuating but case‐irrelevant information about a target in a date‐rape trial (i.e., either the defendant or the victim/witness) would increase attributions of responsibility for that target and would thus influence judgments of defendant guilt. As predicted, merely adding trivial information, such as the victim's age, college major, and city of residence, to the rape trial vignette decreased judgments of guilt for the defendant; whereas adding corresponding information regarding the defendant increased judgments of his guilt. Ratings of perceived similarity to defendant and victim correlated significantly with responsibility and guilt, but were unaffected by the information manipulation. We suggest that target information increases target salience, which results in an increase of attributions of responsibility.     

Familiarity impacts person perception

We investigated the effects of familiarity on person perception. We predicted that familiarity would increase non‐analytic processing, reducing attention to and the impact of individuating information, and increasing the impact of category labels on judgments about a target person. In two studies participants read either incriminating or exculpatory individuating information about a defendant in a criminal case and made judgments of guilt. In Study 1, participants were subliminally exposed to the defendant's photo, another matched photo, or no photo before seeing the evidence. Participants familiar with the defendant's photo both processed and used the individuating information less. In Study 2, participants were subtly made familiar or not with the incriminating and exculpatory information itself, and the defendant was described either as a priest or as a skinhead. Familiarity with the information reduced attention to its content and also tended to increase reliance on category information in guilt judgments. Copyright © 2006 John Wiley & Sons, Ltd.     

Effects of pre‐trial publicity and jury deliberation on juror bias and source memory errors

We examined the effects of exposure to pre‐trial publicity (PTP) and jury deliberation on juror memory and decision making. Mock jurors either read news articles containing negative PTP or articles unrelated to the trial. They later viewed a videotaped murder trial, after which they either made collaborative group decisions about guilt or individual decisions. Finally, all participants independently attributed specific information as having been presented during the trial or in the news articles. Exposure to PTP significantly affected guilty verdicts, sentence length, perceptions of defendant credibility, and misattributions of PTP as having been presented as trial evidence. Jury deliberation had significant effects on jury verdicts, perceptions of defendant credibility, source memory for trial items, and confidence in source memory judgements, but did not affect sentences or critical source memory errors. Copyright © 2006 John Wiley & Sons, Ltd.     

An Examination of Happiness, Racism, and Demographics on Judgments of Guilt

A policy-capturing study was conducted to evaluate the roles of both plaintiff and defendant race and gender on judgments of criminal guilt in either an assault or a theti case. It was hypothesized that defendant gender and race would affect likelihood of guilt ratings. Moreover, mock jurors' dispositional happiness, scores of modern racism, and race and gender were explored as potential influences on their decision-making policies and judgments. As predicted, strong support was found for the role of defendant gender on judgments of guilt. However, defendant race did not significantly impact guilt ratings. Post hoc analses revealed the importance of race and gender of the victim to juror decisions. In addition, participants' own race and gender played signiticant roles in the decisionmaking policies that were produced. Limitations of the study are discussed. as are topics for future research.     

Will jurors correct for evidence interdependence in their verdicts? It depends

Throughout an investigation, pieces of evidence are likely to contaminate one another, yet at trial jurors are expected to treat pieces of evidence as if they are independent. Are jurors able to understand potential evidence contamination? The present study showed mock jurors a videotaped trial simulation. Participants were randomly assigned to hear testimony regarding one piece of evidence, two pieces of independent evidence, or two pieces of interdependent evidence. The study tested the hypothesis that jurors who hear evidence that is interdependent will be just as likely to find the defendant guilty as jurors who hear about two pieces of independent evidence. When an eyewitness's identification was the uncontaminated piece of evidence, our hypothesis was supported. However, when the confession was the uncontaminated piece of evidence, jurors seemed to understand that one piece of evidence had been influenced by another and adjusted their beliefs about the defendant's guilt accordingly. This study supports the conclusion that jurors can sometimes identify and correct for evidence contamination in their perceptions of a defendant's guilt. Implications for reform support are discussed.     

Race,Rape, and Bias: Distortion of Prior Odds and Meaning Changes

Two experiments were conducted to investigate how racial bias affects juror decision making. Three sources of bias were studied: (1) prior probabilities of guilt, (2) distortion of the meaning of evidence, and (3) differential weighting of information. A paired comparison technique employed in the first study revealed that pretrial probabilities of guilt were greater when the victim was White than when she was Black. In the second experiment, a different group of subjects viewed one of four videotaped simulated rape trials in which seven segments of testimony had been previously rated as pro-prosecution, pro-defense, or neutral. During the trial, subjects rated each segment on three different scales: prosecution, defense, and degree of defendant guilt. Results indicated that neutral evidence was seen as more favorable to prosecution for a White victim compared to a Black victim. Evidence which favored either prosecution or defense was not distorted. Regression analyses revealed a positive relationship between estimates of guilt and distortion of evidence. The weight or importance of the evidence did not vary as a function of victim or defendant race. Years of recommended imprisonment indicated greater severity toward the Black assailant of a White woman. The results suggest that bias in favor of White victims occurs both in the assessment of pretrial probabilities and perception of evidence.     

Alibi Believability: The Effect of Prior Convictions and Judicial Instructions

Undergraduates (N = 339) listened to a simulated police interview with a defendant concerning his alibi. We studied the impact of (a) the strength of the alibi evidence; (b) defendant's prior convictions; (c) judge's instructions on prior conviction evidence; and (d) perceivers' need for cognition (NFC) on alibi believability and defendant guilt ratings. Defendants previously convicted of the same crime as the current charge were seen as more likely to be guilty than defendants previously convicted of a different crime. Judge's instructions did not affect guilt ratings. NFC was less influential than anticipated, but did affect participants' understanding and recall of judicial instructions. Strong alibis were seen as more believable and led to lower guilt ratings than weak alibis.     

What's Fair When a Child Testifies?1

Undergraduates (N = 385) watched a 2-hr, videotaped, mock trial of a child sexual abuse case. The child testified in open court, with a barrier between the child and the defendant, or via closed circuit television. Students enacted the role of a juror, sibling of the defendant, or sibling of the mother of the victim. The judge either did or did not warn jurors that the barrier or video should not be considered evidence of the defendant's guilt. Use of the barrier or video did not influence guilty votes, the credibility of witnesses, nor the perceived fairness of the trial for jurors. Siblings of the defendant perceived these procedures to be biased and their use as unfair. Increased publicity about the use of barriers and closed-circuit television when children testify is recommended to reduce objections to these procedures.     

Effects of Native American Race, Intoxication, and Crime Severity on Judgments of Guilt

The effects of Native American race, crime severity, and intoxication on 293 college students' judgments of guilt were investigated. Participants read vignettes of a robbery or a robbery resulting in murder committed by a male defendant with a Native American or a White European surname. The defendant was described as highly intoxicated in half of the conditions. A 2 × 2 × 2 ANOVA revealed a marginally significant 3-way interaction. In the robbery–murder condition, the intoxicated Native American defendant was judged as guiltier than the Native American defendant with no intoxication information. We labeled this a stereotypical drunken-Indian bias. The results suggested that judgments given by lower and higher prejudiced participants canceled each other out.     

How the Defendant's Emotion Level Affects Mock Jurors' Decisions When Presentation Mode and Evidence Strength Are Varied1

Two experiments (N= 443) were conducted to investigate the effects of a defendant's emotion level during testimony on mock jurors' decisions. In Experiment 1, the defendant's level of emotion (low, moderate, high) and mode of presentation (audio, video) were varied. The defendant displaying a low level, as opposed to a higher level of emotion was perceived as more guilty and less credible. In Experiment 2, using only the video mode, emotion level and evidence strength (strong, weak) were varied. Defendant emotion level tended to affect jurors' decisions only when the evidence against the defendant was weak (i.e., a stronger display of emotion was associated with a lower proportion of guilty verdicts, shorter sentence assignments, and perceptions of a more honest defendant). Path analyses for both experiments indicate that the effects of emotion on perceived guilt level are mediated by perceptions of the defendant (e.g., the defendant's level of honesty). Implications of using defendant emotion level for determining guilt are discussed.