The effects of consensus requirements and multiple decisions on mock juror verdict preferences.

Davis, J. H., Holt, R. W., Spitzer, C. E., & Stasser, G. (1981). The effects of consensus requirements and multiple decisions on mock juror verdict preferences. Journal of Experimental Social Psychology, 17, 1-15.

After watching a simulated rape trial, prerecorded on videotape, mock jurors either did or did not expect to sentence a defendant following deliberation with or without a group verdict required. Both sentencing expectation and verdict requirement significantly elevated jurors’ preference for conviction (and average ratings of guilt likelihood). Closer analyses of personal changes (before and after deliberation) in the distribution of opinions suggested that majorities favoring not guilty were more influential than guilty-favoring majorities; and, somewhat unexpectedly, minorities in juries which deliberated without a verdict required were more likely to change personal opinions than minorities in juries required to render a verdict. The overall social decision scheme confirmed earlier observations about the importance of the initial majority in determining the verdict; but the majority did not always prevail and there was a marked asymmetry (“defendant protection”) in its action.

Slight tendency for juries to convict more when responsible for verdict as well as sentencing. SDS characterized by majority influence plus asymmetrical defendant protection bias.

http://www.sciencedirect.com/science/article/pii/0022103181900020