Studied the effect of a normative model (maximization of expected value) upon group and individual choice. 109 MBA students in a Lain square research design chose between two alternatives differing in expected value and in range of outcomes. Group choices were significantly (p < .05) closer to those predicted by the normative model than were individual choices. This difference was not due only to information about the presence and applicability of the normative model but rather it was due to the persuasiveness of the model in a group as a cogent and correct solution to the choice dilemma. Task instructions emphasizing the rewards from risk taking produced significantly more choices (p < .05) of the riskier alternative, particularly by individuals as opposed to groups, than did instructions emphasizing the penalties of risk taking. ‘Risky’ and ‘conservative’ shifts in choice between groups and individuals were explicable through knowledge of the influence of the normative model in individual and group choice.