Group risk-taking under various group decision schemes

This study examined individual choice behavior when it occurs in groups engaged in joint decision-making. Ninety-six subjects made binary choices between “risky” and “conservative” alternatives acting alone and acting as members of three-man groups in a series of 360 trials. The groups operated under the majority rule, unanimity, and the so-called “minimal quorum” rule. It was found that under unanimity and the minimal quorum rule there were strong pressures toward uniformity. However, individual members in these groups did not succumb to these pressures by modifying their overall choice preferences. Instead they arranged their sequences of choices so that the joint choice of all members would be congruent with their acceptable level of risk-taking. The findings also indicated that there was a slight shift toward conservatism when individuals joined groups. The results on individual risk-taking supported a parameter-free model, and the model also accommodated the present group data when some new assumptions were made about the effects of pressures toward uniformity.