Matched Groups and the Risky Shift Phenomenon: a Defence of the Extreme Member Hypothesis

A classification of hypotheses concerning the ‘risky‐shift’ phenomenon was suggested, which was based on three broad approaches. In order to determine which of the three main explanations of the phenomenon is most likely, an experiment was designed to counteract the effects of individual persuasion within the group situation. This was achieved by matching the members of the experimental groups so that all had accepted the same probability levels in the initial, alone, condition of the Choice Dilemmas task. This led to a small, non‐significant risky shift following group discussion which was of comparable size to the small shift found in controls who repeated the alone condition. It is suggested that individual persuasion in addition to familiarization with the problems leads groups to make riskier decisions.