Biomedical subjects

Steven D Penrod

Publications and source records attributed to Steven D Penrod.

5 recordsLinked to original sources

PubMed2006

Mugshot exposure effects: Retroactive interference, mugshot commitment, source confusion, and unconscious transference.

More than 25 years of research has accumulated concerning the possible biasing effects of mugshot exposure to eyewitnesses. Two separate metaanalyses were conducted on 32 independent tests of the hypothesis that prior mugshot exposure decreases witness accuracy at a subsequent lineup. Mugshot exposure both significantly decreased proportion correct and increased the false alarm rate, the effect being greater on false alarms. A mugshot commitment effect, arising from the identification of someone in a mugshot, was a substantial moderator of both these effects. Simple retroactive interference, where the target person is not included among mugshots and no one in a mugshot is present in the subsequent lineup, did not significantly impair target identification. A third metaanalysis was conducted on 19 independent tests of the hypothesis that failure of memory for facial source or context results in transference errors. The effect size was more than twice as large for "transference" studies involving mugshot exposure in proximate temporal context with the target than for "bystander" studies with no subsequent mugshot exposure.

Confusion↗

PubMed2004

A meta-analytic review of the effects of high stress on eyewitness memory.

In the past 30 years researchers have examined the impact of heightened stress on the fidelity of eyewitness memory. Meta-analyses were conducted on 27 independent tests of the effects of heightened stress on eyewitness identification of the perpetrator or target person and separately on 36 tests of eyewitness recall of details associated with the crime. There was considerable support for the hypothesis that high levels of stress negatively impact both types of eyewitness memory. Meta-analytic Z-scores, whether unweighted or weighted by sample size, ranged from -5.40 to -6.44 (high stress condition-low stress condition). The overall effect sizes were -.31 for both proportion of correct identifications and accuracy of eyewitness recall. Effect sizes were notably larger for target-present than for target-absent lineups, for eyewitness identification studies than for face recognition studies and for eyewitness studies employing a staged crime than for eyewitness studies employing other means to induce stress.

Child↗

PubMed2003

Web-based research: methodological variables' effects on dropout and sample characteristics.

Previous research has made a beginning in addressing the importance of methodological differences in Web-based research. The present paper presents four studies investigating whether sample type, financial incentives, time when personal information is requested, table design, and method of obtaining informed consent influence dropout and sample characteristics (both demographics and measured attitudes). Undergraduates were less likely to drop out than nonstudents, and nonstudents offered a financial incentive were less likely to drop out than those offered no incentive. Complex tables, tables that were too wide, requests for personal information on the first page, and the imposing of additional informed consent procedures each provoked early dropout. As was expected, nonstudents and those presented with complex tables showed more measurement error and attitude differences. Asking for personal information and imposing additional consent procedures affected the demographic makeup, raising challenges to external validity.

Adult↗

PubMed2002

Fractional factorial designs for legal psychology.

Researchers considering novel or exploratory psycholegal research are often able to easily generate a sizable list of independent variables (IVs) that might influence a measure of interest. Where the research question is novel and the literature is not developed, however, choosing from among a long list of potential variables those worthy of empirical investigation often presents a formidable task. Many researchers may feel compelled by legal psychology's heavy reliance on full-factorial designs to narrow the IVs under investigation to two or three in order to avoid an expensive and unwieldy design involving numerous high-order interactions. This article suggests that fractional factorial designs provide a reasonable alternative to full-factorial designs in such circumstances because they allow the psycholegal researcher to examine the main effects of a large number of factors while disregarding high-order interactions. An introduction to the logic of fractional factorial designs is provided and several examples from the social sciences are presented.

Confounding Factors, Epidemiologic↗

PubMed2002

Studying pretrial publicity effects: new methods for improving ecological validity and testing external validity.

Although research examining the effects of pretrial publicity (PTP) on individuals' appraisals of a defendant and verdict decision making generally has been found to be internally valid, the external validity has been questioned by some social scientists as well as lawyers and judges. It is often proposed that the verisimilitude (or ecological validity) ofthe research should be increased in the service of increasing external validity; however, increasing verisimilitude can be costly in terms of both time and money. It is proposed that the Internet is a viable means of conducting PTP research that allows high verisimilitude without high costs. This is demonstrated with a study in which we used the Internet to examine PTP effects in an actual trial as it was taking place. Successful use of the Internet to conduct experimental research in other areas of psychology and law is discussed, as well as the importance of future research examining whether independent variables interact with methods in ways that undermine the generalizability of research findings.

Adult↗