Social Inference Processes in Juror Judgments of Multiple-Offense Trials

• NCJ Number: 103303
• Journal: Journal of Personality and Social Psychology Volume: 47 Issue: 4 Dated: (1984) Pages: 749-765
• Author(s): S Tanford; S Penrod
• Date Published: 1984
• Length: 17 pages
• Grant Number(s): 81-IJ-CX-0048
• Sponsoring Agency: National Institute of Justice (NIJ); US Dept of Justice NIJ Pub
• Publication Format: Article
• Publication Type: Report (Study/Research)
• Language: English
• Country: United States of America

Annotation

The effects of joinder (single trial of a defendant for multiple offenses) were investigated empirically, with emphasis on the social and psychological mechanisms underlying judgmental biases.

Abstract

Subjects were 714 qualified jurors who had been summoned for jury service in Wisconsin in 1981-1982 and 18 undergraduate registered voters. A control group judged a trial that consisted of a single burglary charge; experimental groups judged a trial that combined this charge with two additional charges. Independent variables included charge and evidence similarity (similar, dissimilar, identical) and judge's instructions (present or absent). Results indicate that joining multiple charges increases the proportion of individual guilty verdicts on the target charge relative to the same charge tried by itself. Joinder also increased the frequency of guilty and hung group verdicts. The effects of charge and evidence similarity were groups judged a trial that combined this charge with two additional charges. Independent variables included charge and evidence similarity (similar, dissimilar, identical) and judge's instructions (present or absent). Results indicate that joining multiple charges increases the proportion of individual guilty verdicts on the target charge relative to the same charge tried by itself. Joinder also increased the frequency of guilty and hung group verdicts. The effects of charge and evidence similarity were negligible compared to the effects of joinder. A very strong set of jury instructions designed to eliminate biasing joinder effects had no effect on verdict judgments or any other dependent measures. Results support the proposition that joinder creates a negative impression of the defender that can produce confusion, accumulation of evidence, and inferences of criminality. 63 references. (Author abstract modified)