Davis, J. H., Stasser, G., Spitzer, C. E., & Holt, R. W. (1976). Changes in group members’ decision preferences during discussion: An illustration with mock juries. Journal of Personality and Social Psychology, 34, 1177-1187.
Assessed the changing personal decisions of mock jurors (870 undergraduates) by periodic polling during deliberation. Six-person mock juries informed that they would subsequently be publicly accountable (queried by a panel of experts) differed considerably in their pattern of opinion change over time from mock juries whose deliberations would remain private. For one thing, public juries moved much faster away from a guilty consensus near the end of deliberation, while private juries exhibited little change in their tendency to move with approximately equal speed toward guilty or not-guilty verdicts. These and other dynamic changes in personal verdict preferences of jurors were assessed by the construction of state matrices and associated statistics, permitting relevant comparisons over time and between conditions. Interpretations of results were also aided by S reactions to postsession questionnaires.
No impact of polling secrecy on jury verdicts. Private polling produced fast initial opinion change that tailed off; public polling resulted in slow initial movement that gained speed. Shifts toward not guilty more frequent than guilty.