Eyewitness accuracy and confidence: within- versus between-subjects correlations

Previous researchers using between-subjects comparisons have found eyewitness confidence and accuracy to be only negligibly correlated. In this study, we examined the predictive power of confidence in within-subject terms. Ninety-six subjects answered, and made confidence ratings for, a series of questions about a crime they witnessed. The average between-subjects and within-subject accuracy-confidence correlations were comparably low: r = .14 (p less than .001) and r = .17 (p less than .001), respectively. Confidence is neither a useful predictor of the accuracy of a particular witness nor of the accuracy of particular statements made by the same witness. Another possible predictor of accuracy, response latency, correlated only negligibly with accuracy (r = -.09 within subjects), but more strongly with confidence (r = -.27 within subjects). This pattern was obtained for both between-subjects and within-subject comparisons. The theoretical and practical implications of these results are discussed.     

Information Consistency and Perceptual Set: Overcoming the Mental Retardation “Schema”1

Two factors that were thought to promote or inhibit schema-based or stereotypic responding in impression formation were examined in two experiments. Subjects were asked to provide evaluations of artwork supposedly painted by either mentally retarded or nonretarded children. Based on previous research, it was assumed that subjects would expect relatively poor quality artwork from retarded children, which would he consistent with a negative schema that they maintain for this group. It was also predicted that this negative schema would result in cursory examinations and unfavorable evaluations of the retarded artists' artwork, but only when the evaluative conditions were conducive to schematic responding. Specifically, the schema effect was predicted to occur when the artwork was of poor quality and subjects were instructed to provide an overall evaluation of the painting rather than an assessment of its specific characteristics. No derogation was expected when these factors were not present. Results supported these hypotheses. Additional analyses indicated that subjects were conducting a cursory search of the target stimuli when conditions favored schema-based responding.     

The construction and validation of a juror bias scale

A questionnaire was constructed to measure individual differences in pretrial bias among jurors. The final Likert scale, called the Juror Bias Scale (JBS), contains 17 items—8 that reflect pretrial expectancies that defendants, in general, commit the crimes with which they are charged and 9 that reflect the value attached to conviction and punishment. The scale is internally consistent and test-retest reliable. Scores are uncorrelated with social desirability, moderately correlated with I-E control and belief in a just world, and more highly correlated with authoritarianism. In one validation experiment, student jurors were exposed to three trial presentations in a laboratory setting. Overall, subjects classified as prosecution biased were more conviction prone and adopted a less stringent standard of reasonable doubt. In a second study, community jurors watched one of two videotaped mock trials in a courtroom. Prosecution-biased subjects asserted a higher probability that the defendent committed the crime and rendered a higher percentage of guilty verdicts than defense-biased subjects for one of the two trials. JBS scores were unrelated to all demographic variables, but were significantly correlated with political views. The potential uses and limitations of the JBS are discussed.     

The psychology of confessions: A comparison of expert and lay opinions

Despite a body of confessions research that is generally accepted in the scientific community, courts often exclude experts on the ground that such testimony would not assist the jury, which can use its common sense. To examine whether laypeople know the contents of expert testimony on confessions, we asked 151 lay participants to indicate their beliefs about 30 confession‐related statements used in a recent survey of 87 confession experts (Kassin et al., American Psychologist, 2018, 73, 63–80). Participants agreed with experts on only 10 of the 30 propositions, suggesting that much of the psychology of confessions is not common knowledge and that expert testimony can assist the trier of fact.     

Rearing practices and impulsivity/hyperactivity symptoms in relation to inflated responsibility and obsessive‐compulsive symptoms

Smári, J., Rúrik Martinsson, D., & Einarsson, H. (2010). Rearing practices and impulsivity/hyperactivity symptoms in relation to inflated responsibility and obsessive‐compulsive symptoms. Scandinavian Journal of Psychology, 51, 392–397. The aim of the study was to investigate potential precursors of inflated responsibility (responsibility attitudes) and obsessive‐compulsive (OCD) symptoms. It was argued that both parental overprotection and impulsivity, separately and in interaction with each other, contribute to inflated responsibility and OCD symptoms. In a large sample of young adults (N = 570), self‐report measures of OCD symptoms (OCI‐R), responsibility attitudes (RAS), anxiety/depression (HADS), rearing practices (EMBU), present and past impulsivity/hyperactivity symptoms (IMP/HY) were administered. Overprotection as well as IMP/HY were found to predict OCD symptoms as well as inflated responsibility. Finally, a significant interaction was found between IMP/HY and overprotection with regard to both OCD symptoms and inflated responsibility. This effect reflected that IMP/HY was more strongly related to OCD symptoms and responsibility in people who had not been overprotected than in people who had been. Conversely overprotection was related to OCD symptoms and responsibility in people low but not in people high in IMP/HY. The results seem to indicate that the inadequacy between offer and need for parental control may play a role in the development of OCD symptoms.     

New application of psychology to law: Improving forensic evidence and expert witness contributions

Psychology has made a tremendous contribution to law by showing the malleability of eyewitness perception and memory, and developing best practices for obtaining eyewitness identifications. We suggest that even expert scientific witnesses, which the court heavily relies on as objective and impartial, are also susceptible to bias from various psychological influences. For example, forensic examiners’ interactions with detectives and exposure to information about the case can bias their judgments. We discuss the ten commentaries on these issues across a range of forensic science domains, and affirm what reforms are needed.     

On the Presumption of Evidentiary Independence: Can Confessions Corrupt Eyewitness Identifications?

ABSTRACT— A confession is potent evidence, persuasive to judges and juries. Is it possible that a confession can also affect other evidence? The present study tested the hypothesis that a confession will alter eyewitnesses' identification decisions. Two days after witnessing a staged theft and making an identification decision from a lineup that did not include the thief, participants were told that certain lineup members had confessed or denied guilt during a subsequent interrogation. Among those participants who had made a selection but were told that another lineup member confessed, 61% changed their identifications. Among those participants who had not made an identification, 50% went on to select the confessor when his identity was known. These findings challenge the presumption in law that different forms of evidence are independent and suggest an important overlooked mechanism by which innocent confessors are wrongfully convicted: Potentially exculpatory evidence is corrupted by a confession itself.