Janis (1972) proposed that groupthink is essentially a stress-reduction process. Cohesive groups reduce the stress of decision making by suppressing critical inquiry. Theoretically, groupthink could be prevented in cohesive groups if the stress could be diffused by other factors. We investigated the effects of task structure (decision-making procedures) and an individual factor (dominance) on the quality of group decision making, anxiety, and symptoms of groupthink. Students (n = 112) participated in twenty-eight 4-person, mixed-sex groups. Groups composed of highly dominant members made higher quality decisions, exhibited lower state anxiety, and took more time to reach a decision. They also tended to make more statements of disagreement and agreement, and to report more group influence on the members. Decision-making procedures had little effect on the decision process.