Police officers’ credibility judgments: Accuracy and estimated ability

Is It the Judge, the Sender, or Just the Individual Message? Disentangling Person and Message Effects on Variation in Lie-Detection Judgments

Research suggests that people differ more in their ability to lie than in their ability to detect lies. However, because studies have not treated senders and messages as separate entities, it is unclear whether some senders are generally more transparent than others or whether individual messages differ in their transparency of veracity regardless of senders. Variance attributable to judges, senders, and messages was estimated simultaneously using multiple messages from each sender (totaling more than 45,000 judgments). The claim that the accuracy of a veracity judgment depends on the sender was not supported. Messages differed in their detectability (21% explained variance), but senders did not. Message veracity accounted for most message variation (16.8% of the total variance), but other idiosyncratic message characteristics also contributed significantly. Consistent with the notion that a (mis)match between sender demeanor and veracity determines accuracy, lie and truth detectability differed individually within senders. Judges primarily determined variance in lie-versus-truth classifications (12%) and in confidence (46%) but played no role regarding judgment accuracy (< 0.01%). This work has substantial implications for the design and direction of future research and underscores the importance of separating senders and messages when developing theories and testing derived hypotheses.

(The null) Importance of police experience on intuitive credibility of people with intellectual disabilities

In the present study, the intuitive ability of police to discriminate between real and false statements of people with mild and moderate (IQ range=50-80, average=60.0) intellectual disabilities (ID) was analyzed. The assessments issued by groups with different levels of experience in police techniques (psychology students, and police officers) were compared. The results showed no differences between the two groups in their ability to discriminate (d'=0.785 and d'=0.644, respectively). When the experience of the police was taken into consideration, no differences were found between "experienced" and "novice" police officers (d'=0.721 and d'=0.582, respectively). No differences were found in response criteria, which were neutral in all cases. Moreover, 34.73% of cases evaluated by the inexperienced group were incorrectly discriminated, in comparison to the 37.75% of incorrect assessments made by police. The implications of the limited ability of intuition to discriminate between real and simulated victims with ID, which did not yield significant differences between experienced and inexperienced assessors in obtaining and assessing statements, are discussed. In light of the results of this study, it is concluded that adequate resources and standardized procedures to properly address people with ID who come into contact with the police and judicial institutions need to be provided.

Deception detection, transmission, and modality in age and sex

This study is the first to create and use spontaneous (i.e., unrehearsed) pro-social lies in an ecological setting. Creation of the stimuli involved 51 older adult and 44 college student “senders” who lied “authentically” in that their lies were spontaneous in the service of protecting a research assistant. In the main study, 77 older adult and 84 college raters attempted to detect lies in the older adult and college senders in three modalities: audio, visual, and audiovisual. Raters of both age groups were best at detecting lies in the audiovisual and worst in the visual modalities. Overall, college students were better detectors than older adults. There was an age-matching effect for college students but not for older adults. Older adult males were the hardest to detect. The older the adult was the worse the ability to detect deception.

The Effects of Group Factors on Deception Detection Performance

Deception has been an important problem in interactive groups, impeding effective group communication and group work, yet deception detection in such a context remains understudied. Extrapolated from the interpersonal deception theory (IDT) and group composition research in cooperative contexts, this research proposes that group factors, including diversity and familiarity, have influence on the performance of deception detection. The measurement of group performance was not limited to success, as previous deception studies did, but included efficiency as well because it is fundamental to the effectiveness of deception detection. An analysis of data collected from a real-world online community found that behavioral familiarity had a positive effect, and gender diversity had a negative effect, on group success in deception detection. In addition, behavioral familiarity had a negative effect and functional diversity had a positive effect on the group efficiency of deception detection. The findings not only extend IDT in several important ways but also suggest the need to distinguish between noncooperative and cooperative groups, an important theoretical implication for group composition research.

Police lie detection accuracy: the effect of lie scenario

Although most people are not better than chance in detecting deception, some groups of police professionals have demonstrated significant lie detection accuracy. One reason for this difference may be that the types of lies police are asked to judge in scientific experiments often do not represent the types of lies they see in their profession. Across 23 studies, involving 31 different police groups in eight countries, police officers tested with lie detection scenarios using high stakes lies (i.e., the lie was personally involving and/or resulted in substantial rewards or punishments for the liar) were significantly more accurate than law enforcement officials tested with low stakes lies. Face validity and construct validity of various lie scenarios are differentiated.

The reliability of lie detection performance

We examined whether individuals' ability to detect deception remained stable over time. In two sessions, held one week apart, university students viewed video clips of individuals and attempted to differentiate between the lie-tellers and truth-tellers. Overall, participants had difficulty detecting all types of deception. When viewing children answering yes-no questions about a transgression (Experiments 1 and 5), participants' performance was highly reliable. However, rating adults who provided truthful or fabricated accounts did not produce a significant alternate forms correlation (Experiment 2). This lack of reliability was not due to the types of deceivers (i.e., children versus adults) or interviews (i.e., closed-ended questions versus extended accounts) (Experiment 3). Finally, the type of deceptive scenario (naturalistic vs. experimentally-manipulated) could not account for differences in reliability (Experiment 4). Theoretical and legal implications are discussed.

On the psychology of confessions: does innocence put innocents at risk?

The Central Park jogger case and other recent exonerations highlight the problem of wrongful convictions, 15% to 25% of which have contained confessions in evidence. Recent research suggests that actual innocence does not protect people across a sequence of pivotal decisions: (a) In preinterrogation interviews, investigators commit false-positive errors, presuming innocent suspects guilty; (b) naively believing in the transparency of their innocence, innocent suspects waive their rights; (c) despite or because of their denials, innocent suspects elicit highly confrontational interrogations; (d) certain commonly used techniques lead suspects to confess to crimes they did not commit; and (e) police and others cannot distinguish between uncorroborated true and false confessions. It appears that innocence puts innocents at risk, that consideration should be given to reforming current practices, and that a policy of videotaping interrogations is a necessary means of protection.

"I'd know a false confession if I saw one": a comparative study of college students and police investigators

College students and police investigators watched or listened to 10 prison inmates confessing to crimes. Half the confessions were true accounts; half were false--concocted for the study. Consistent with much recent research, students were generally more accurate than police, and accuracy rates were higher among those presented with audiotaped than videotaped confessions. In addition, investigators were significantly more confident in their judgments and also prone to judge confessors guilty. To determine if police accuracy would increase if this guilty response bias were neutralized, participants in a second experiment were specifically informed that half the confessions were true and half were false. This manipulation eliminated the investigator response bias, but it did not increase accuracy or lower confidence. These findings are discussed for what they imply about the post-interrogation risks to innocent suspects who confess.

The Psychology of Confessions: A Review of the Literature and Issues

Recently, in a number of high-profile cases, defendants who were prosecuted, convicted, and sentenced on the basis of false confessions have been exonerated through DNA evidence. As a historical matter, confession has played a prominent role in religion, in psychotherapy, and in criminal law-where it is a prosecutor's most potent weapon. In recent years, psychologists from the clinical, personality, developmental, cognitive, and social areas have brought their theories and research methods to bear on an analysis of confession evidence, how it is obtained, and what impact it has on judges, juries, and other people. Drawing on individual case studies, archival reports, correlational studies, and laboratory and field experiments, this monograph scrutinizes a sequence of events during which confessions may be obtained from criminal suspects and used as evidence. First, we examine the preinterrogation interview, a process by which police target potential suspects for interrogation by making demeanor-based judgments of whether they are being truthful. Consistent with the literature showing that people are poor lie detectors, research suggests that trained and experienced police investigators are prone to see deception at this stage and to make false-positive errors, disbelieving people who are innocent, with a great deal of confidence. Second, we examine the Miranda warning and waiver, a process by which police apprise suspects of their constitutional rights to silence and to counsel. This important procedural safeguard is in place to protect the accused, but researchers have identified reasons why it may have little impact. One reason is that some suspects do not have the capacity to understand and apply these rights. Another is that police have developed methods of obtaining waivers. Indeed, innocent people in particular tend to waive their rights, naively believing that they have nothing to fear or hide and that their innocence will set them free. Third, we examine the modern police interrogation, a guilt-presumptive process of social influence during which trained police use strong, psychologically oriented techniques involving isolation, confrontation, and minimization of blame to elicit confessions. Fourth, we examine the confession itself, discussing theoretical perspectives and research on why people confess during interrogation. In particular, we focus on the problem of false confessions and their corrupting influence in cases of wrongful convictions. We distinguish among voluntary, compliant, and internalized false confessions. We describe personal risk factors for susceptibility to false confessions, such as dispositional tendencies toward compliance and suggestibility, youth, mental retardation, and psychopathology. We then examine situational factors related to the processes of interrogation and show that three common interrogation tactics-isolation; the presentation of false incriminating evidence; and minimization, which implies leniency will follow-can substantially increase the risk that ordinary people will confess to crimes they did not commit, sometimes internalizing the belief in their own culpability. Fifth, we examine the consequences of confession evidence as evaluated by police and prosecutors, followed by judges and juries in court. Research shows that confession evidence is inherently prejudicial, that juries are influenced by confessions despite evidence of coercion and despite a lack of corroboration, and that the assumption that "I'd know a false confession if I saw one" is an unsubstantiated myth. Finally, we address the role of psychologists as expert witnesses and suggest a number of possible safeguards. In particular, we argue that there is a need to reform interrogation practices that increase the risk of false confessions and recommend a policy of mandatory videotaping of all interviews and interrogations.