Inadmissible evidence and juror verdicts

• Published in: Journal of personality and social psychology Vol. 40; no. 3; pp. 453 - 463
• Main Authors: Thompson, William C, Fong, Geoffrey T, Rosenhan, D. L
• Format: Journal Article
• Language: English
• Published: Washington, D.C American Psychological Association 01-03-1981
• Subjects: Adjudication; Decision Making; DECISION-MAKING AND GAME THEORY; EVIDENCE; Experimental Instructions; HEAVILY EMPHASIZES METHODOLOGY OR TECHNIQUE OF STUDY; Human; JURIES AND JURY BEHAVIOR; LAW AND LEGAL SYSTEMS
• ISSN: 0022-3514; 1939-1315
• DOI: 10.1037/0022-3514.40.3.453

288 mock jurors watched videotapes of a realistic simulated trial and rendered verdicts as individuals before deliberation and as groups after deliberation. In a 3 × 2 design, the trial evidence and judge's instructions were varied. The trial contained inadmissible evidence supporting conviction, inadmissible evidence supporting acquittal, or no inadmissible evidence. The judge's instructions emphasized the importance either of protecting the defendant's due process rights or of reaching an accurate verdict. Jurors who received proacquittal inadmissible evidence were less likely to convict than those who received either proconviction inadmissible evidence or no inadmissible evidence. The conviction rates in the latter 2 conditions did not differ significantly. The variation in judge's instructions had no effect. Paradoxically, jurors who received proconviction inadmissible evidence thought that their verdicts had been influenced by it, whereas those who received proacquittal inadmissible evidence thought that their verdicts has not been influenced by it. Jurors' evaluations of the strength of admissible evidence were not influenced by the presence of inadmissible evidence. (20 ref)