Kameda, T. (1991). Procedural influence in small-group decision making: Deliberations style and assigned decision rule. Journal of Personality and Social Psychology, 61, 245-256.
Six-person mock juries discussed 2 civil cases in which applicable law required either a conjunctive or a disjunctive assessment of key evidence to find a defendant liable. Under these task requirements official decision rule and jury deliberation style, analogous to the verdict-driven/evidence-driven distinction, were manipulated. Consistent with predictions derived from a probabilistic model, deliberation style interacted with the task requirement in affecting a jury verdict. The evidence-driven style yielded a liable verdict more often in the conjunctive case than the verdict-driven style, whereas this pattern was reversed in the disjunctive case. These results were replicated in Exp 2. Although the decision rule factor had no sizable effect on group decisions, it affected members’ postdecision responses, such as opinion change rates. Implications of these procedural influences for administrative decision contexts are discussed.
<1>Deliberation style interacted with verdict criteria. With disjunctive criteria, more liability verdicts resulted when jurors instructed to reach verdict preference before deliberation; with conjunctive criteria, more liability verdicts resulted when jury discussed each criterion without jurors making previous judgments. <2>Interaction replicated in 2nd study with case held constant and different jury size.