Acceptance of Uncommon Information into Group Discussion When That Information Is or Is Not Demonstrable

Research on group problem solving and on social cognition suggests that, during group discussion of a decision-making task, member acceptance of an unknown fact will be affected by the demonstrability of a fact's existence and the familiarity of the decision topic. Four-person groups read and discussed facts about a familiar or unfamiliar issue. Some groups could obtain written fact summaries during discussion, while the others could not. We predicted and found a three-way interaction between demonstrability, familiarity, and number of advocates. Verifiable single-advocate facts were accepted into discussion, but unverifiable facts required two advocates. These effects were more pronounced when the topic was familiar. Regression analysis of the influence of individual items on group choice revealed that, for the unfamiliar topic, the number of advocates of an item was directly related to that item's degree of influence only when the item could not be verified. Verifiable single-advocate facts were as influential as any other verifiable fact.