Group versus individual performance: Are N + 1 heads better than one?

Experimental comparisons of groups and individuals were analyzed on four dimensions: task, process, individual differences, and methodology. A standardized terminology based on Lorge, Fox, Davitz, and Brenner was developed to preserve operational definitions in the comparisons of (a) group versus individual, (b) group versus the most competent individual in an aggregate, (c) group versus pooled responses of an aggregate, and (d) group versus math models of performance. Research supported Steiner's theory of process loss but also suggested evidence for process gain. To avoid confounding of group conditions and subject variables, this review-focused on the results of random assignment of subjects to conditions. Belief in the adage that two heads are