Group Decision Making and Normative Versus Informational Influence: Effects of Type of Issue and Assigned Decision Rule

Groups and individuals often shift their preferences following discussion of an issue. Explanations for such shifts typically invoke either informational or normative influence processes. The former refers to influence based on sharing of facts or persuasive arguments about the issue, and the latter refers to conformity to implicit decision norms and others' preferences. We investigated conditions under which one or the other influence mode predominates during discussion. Groups discussed and made decisions on either an intellective issue (attempting to discover the true or correct answer) or a judgmental issue (deciding on the moral, valued, or appropriate position), given either a unanimity or a majority decision rule. The largest shift in preference was found for the judgmental issue decided by unanimity rule. The least satisfaction with both the process and the outcome of discussion was found in groups that decided a judgmental issue under majority rule. Content analysis showed that, as expected, the intellective issue elicited more informational than normative influence, and the judgmental issue provoked more normative than informational influence. This pattern was stronger under unanimity rule than under majority rule. Thus, the mode of influence that predominates in group discussion depends on type of issue, and the degree of dominance is moderated by the decision rule. Possible limitations and extensions of the research are discussed.