Genetically-diverse crowds are wiser

A fundamental question in the social sciences is how collectives of individuals form intelligent judgments. This article tests the hypothesis that genetically-diverse groups make better collective judgments than genetically more homogenous groups. Two studies were conducted (a total of N = 602 participants) in which sets of twins (both monozygotic and dizygotic) were required to perform the task of making numerical judgments. The accuracy of the judgments made by pairs of participants—who were either co-twins (i.e., genetically-related) or were not related—was then compared. The results indicate that the judgments made by unrelated pairs were more accurate than those of the genetically-related twins. Critically, however, this superior performance was found only among monozygotic twins, evidencing the role of genetic relatedness in collective judgment. This research provides the first empirical demonstration of the benefit of genetic diversity for collective judgments, shedding light on the origins of the ‘wisdom of crowds’ phenomenon.