NCJ Number
77855
Journal
Law and Human Behavior Volume: 4 Issue: 4 Dated: special issue (1980) Pages: 243-260
Date Published
1980
Length
18 pages
Annotation
Employing witnesses' level of confidence in their testimony as one of five criteria in deciding the trustworthiness of eyewitness testimony is not supported by a review of 43 separate assessments of the accuracy/confidence relation in eye- and earwitnesses.
Abstract
A recent laboratory study has shown that juror perceptions of witness confidence account for 50 percent of the variance in juror judgments as to witness accuracy. Yet statistics support the notion that the predictability of accuracy from overtly expressed confidence varies directly with the degree of optimality of information processing conditions during encoding of the witnessed event, memory storage, and testing of the witnesses' memory. Low optimal conditions, those mitigating against the likelihood of highly reliable testimony, typically result in a zero correlation of confidence and accuracy. Statistics were gleaned from some 25 studies reporting 43 separate assessments of the accuracy and confidence relation in eye- and earwitnesses. Six of seven forensically relevant laboratory studies exhibit significant positive correlations of confidence and accuracy, using the arbitrary criterion of 70 percent or greater accuracy to define high optimal conditions. However, no clear criteria exist for distinguishing post hoc high from low optimal witnessing conditions in any particular real-life situation. Hence the judiciary should cease their reliance on witness confidence as an index of witness accuracy. Footnotes, tables, reference notes, and 34 references are included. (Author abstract modified)