When crimes are joined at trial

In two experiments, subject-jurors read evidence from actual criminal cases, decided on the guilt of the defendant, and answered several additional questions. The defendant was accused of one charge (murder or rape) or two charges (both murder and rape). In both experiments, the defendant was more likely to be convicted of either crime if the two charges were joined in one trial. Trait ratings indicated that the defendant was perceived in a more negative way when standing trial on two offenses. The order in which the charges were heard had no effect, nor did instructions to subjects to judge the cases separately.Portions of this paper were presented at the American Psychology-Law Society Meeting in Cambridge, Massachusetts, October, 1981. The research was supported by a grant from NSF to Elizabeth Loftus.     

Experimental psychologist as advocate or impartial educator

An important ethical issue surrounds the role of experimental psychologists as experts, namely, whether the expert psychologist should assume the role of advocate or impartial educator. In actual practice, a number of concrete dilemmas arise. These concern the external validity of the studies, the omission of information, and the conducting of special purpose studies, among others. Problems arise whether one plays the role of an advocate or an educator, for which the APA Ethical Principles provide little guidance. A Darwinian (survival of the fittest expert) approach is suggested as a temporary remedy.The author's research relevant to this article has been supported by grants from the National Science Foundation and the National Institute of Mental Health.     

Change blindness can cause mistaken eyewitness identification

The current study investigated the effects of change blindness and crime severity on eyewitness identification accuracy. This research, involving 717 subjects, examined change blindness during a simulated criminal act and its effects on subjects' accuracy for identifying the perpetrator in a photospread. Subjects who viewed videos designed to induce change blindness were more likely to falsely identify the innocent actor relative to those who viewed control videos. Crime severity did not influence detection of change; however, it did have an effect on eyewitness accuracy. Subjects who viewed a more severe crime ($500 theft) made fewer errors in perpetrator identification than those who viewed a less severe crime ($5 theft). This research has theoretical implications for our understanding of change blindness and practical implications for the real‐world problem of faulty eyewitness testimony.     

A retrospective analysis of alcohol in medicolegal postmortems over a period of five years.

Violence and violent death are everyday events in present-day South Africa. Although this phenomenon may be attributed in great part to the sociopolitical environment, the single most important underlying common factor is the presence of alcohol in both the perpetrators of violence and their victims. We retrospectively studied 948 cases of 2,980 medicolegal autopsies done over a 5-year period. We found that 52.5% of cases tested positively for alcohol, with blood alcohol concentration varying from 0.008 to 0.048 g% (mean = 0.18). Male patients were more common and more likely to be positive than female patients. Breakdown of the cases into various modes of death showed that homicides, vehicular accidents, and suicides predominated. The results are in agreement with earlier studies done locally and elsewhere.     

Officers’ memory and stress in virtual lethal force scenarios: Implications for policy and training

ABSTRACT

Sworn law enforcement officers (N?=?151) were exposed to two different simulated lethal force encounters, a motorcycle-traffic-stop (MTS) and a workplace violence incident. Workplace violence incidents (WPV) consisted of two versions: an original version (WVO) and an enhanced version (WVE) with additional tactile and auditory stimuli within the simulation environment. Officers’ recognition memory (immediate and 48?h later), perceived stress, and physiological stress responses were examined. Delayed reporting led to impaired memory for event information in the MTS and perpetrator information in the WVE simulation. Moreover, perpetrator information was remembered more accurately than event information. Two physiological stress markers – alpha amylase and immunoglobulin-a – were correlated with memory for the simulated experiences; however, cortisol and interleukin-6 were not. These findings support current theory related to arousal and memory suggesting that officers should be interviewed as soon as reasonably possible after a lethal force incident. Implications for legal parameters in defining a ‘reasonable officer’ exerting lethal force are considered.     

Do jurors share a common understanding concerning eyewitness behavior?

It would seem that the American judiciary have traditionally viewed knowledge of variables affecting eyewitness behavior as a part of common understanding. The presumption would then be that there is a body of knowledge in this regard that is indeed shared and that this shared understanding conforms substantially to objective reality. Multiple-choice format questionnaires designed to tap such knowledge were administered to two somewhat disparate samples of college students (n=176) and two samples of the citizenry at large in Washington D.C., 46 of whom had not had criminal trial jury experience in the previous five years and 43 of whom had. Across samples the typical respondent's performance was significantly above chance but not at all high in absolute terms. This typical performance involved well above chance levels of accuracy on about half the items and not different from chance accuracy on the others. At least within the college student samples, certain demographic variables were not related to accuracy of response. Likewise, previous criminal trial jury experience did not improve accuracy for the Washington D.C. respondents by an amount that would be practically significant. It was concluded that the common understanding doctrine cannot in general be supported.The work in this report was partially supported by an NSF grant to the second author. Thanks are also due the Washington D.C. Public Defender's Office for their assistance in data collection. The comments and suggestions of Gary Wells and an anonymous reviewer are gratefully acknowledged as well.     

Some facts about “weapon focus”

“Weapon focus” refers to the concentration of acrime witness's attention on a weapon, and the resultant reduction in ability to remember other details of the crime. We examined this phenomenon by presenting subject-witnesses with a series of slides depicting an event in a fast-food restaurant. Half of the subjects saw a customer point a gun at the cashier; the other half saw him hand the cashier a check. In Experiment 1, eye movements were recorded while subjects viewed the slides. Results showed that subjects made more eye fixations on the weapon than on the check, and fixations on the weapon were of a longer duration than fixations on the check. In Experiment 2, the memory of subjects in the weapon condition was poorer than the memory of subjects in the check condition: In Experiment 1 similar, though only marginally significant, performance effects were obtained. These results provide the first direct empirical support for weapon focus.