Biomedical subjects

Jonathan J Koehler

Publications and source records attributed to Jonathan J Koehler.

5 recordsLinked to original sources

PubMed2006

Mock jurors' reactions to selective presentation of evidence from multiple-opportunity searches.

Prior to trial, litigants sometimes conduct broad investigations in which there are multiple opportunities to find supportive evidence by chance alone. During trial, litigants may selectively present only the most helpful evidence uncovered by their investigations. Two experiments examined whether mock jurors appreciate that the evidence they hear at trial may be a selective and unrepresentative sample of underlying facts. The data suggest that people do understand the significance of multiple-opportunity searches for legal inference. However, they may not consider the possibility that evidence was strategically selected from a larger sample space of facts unless that sample space is identified.

Attitude↗

PubMed2005

The coming paradigm shift in forensic identification science.

Converging legal and scientific forces are pushing the traditional forensic identification sciences toward fundamental change. The assumption of discernible uniqueness that resides at the core of these fields is weakened by evidence of errors in proficiency testing and in actual cases. Changes in the law pertaining to the admissibility of expert evidence in court, together with the emergence of DNA typing as a model for a scientifically defensible approach to questions of shared identity, are driving the older forensic sciences toward a new scientific paradigm.

DNA↗

PubMed2004

Thinking about low-probability events. An Exemplar-Cuing theory.

The way people respond to the chance that an unlikely event will occur depends on how the event is described. We propose that people attach more weight to unlikely events when they can easily generate or imagine examples in which the event has occurred or will occur than when they cannot. We tested this idea in two experiments with mock jurors using written murder scenarios. The results suggested that jurors attach more weight to the defendant's claim that an incriminating DNA match is merely coincidental when it is easy for them to imagine other individuals whose DNA would also match than when it is not easy for them to imagine such individuals. We manipulated the difficulty of imagining such examples by varying the description of the DNA-match statistic. Some of the variations that influenced the jurors were normatively irrelevant.

Crime↗

PubMed2003

The misquantification of probative value.

D. Davis and W. C. Follette (2002) purport to show that when "the base rate" for a crime is low, the probative value of "characteristics known to be strongly associated with the crime ... will be virtually nil." Their analysis rests on the choice of an arbitrary and inopposite measure of the probative value of evidence. When a more suitable metric is used (e.g., a likelihood ratio), it becomes clear that evidence they would dismiss as devoid of probative value is relevant and diagnostic.

Criminal Law↗

PubMed2003

A normality bias in legal decision making.

It is important to understand how legal fact finders determine causation and assign blame. However, this process is poorly understood. Among the psychological factors that affect decision makers are an omission bias (a tendency to blame actions more than inactions [omissions] for bad results), and a normality bias (a tendency to react more strongly to bad outcomes that spring from abnormal rather than normal circumstances). The omission and normality biases often reinforce one another when inaction preserves the normal state and when action creates an abnormal state. But what happens when these biases push in opposite directions as they would when inaction promotes an abnormal state or when action promotes a normal state? Which bias exerts the stronger influence on the judgments and behaviors of legal decision makers? The authors address this issue in two controlled experiments. One experiment involves medical malpractice and the other involves stockbroker negligence. They find that jurors pay much more attention to the normality of conditions than to whether those conditions arose through acts or omissions. Defendants who followed a nontraditional medical treatment regime or who chose a nontraditional stock portfolio received more blame and more punishment for bad outcomes than did defendants who obtained equally poor results after recommending a traditional medical regime or a traditional stock portfolio. Whether these recommendations entailed an action or an omission was essentially irrelevant. The Article concludes with a discussion of the implications of a robust normality bias for American jurisprudence.

Decision Making↗