“Genetically-Diverse Crowds Are Wiser”, 2024-12 (; similar):
[pre-registration] 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 homogeneous 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 (ie. 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.
[Keywords: judgment accuracy, decision-making, combining estimates, Wisdom of crowds, genetic diversity, independence of opinion, twin studies]
…In our studies, we asked a sample of twins to make (individually and separately) numerical estimates of quantities. From this pool of estimates, we then created artificial pairs of twins, by pairing the estimates made by two individual twins. Next, we averaged the estimates of the two individuals in the pairs and assessed the accuracy of the combined estimates. This represents the accuracy of the collective judgment of a pair.
…Note that both types of pairs involved the very same participants. The only difference between related and unrelated resided in the way the pairs were (re)arranged by us for analytical purposes, once we had collected their individual estimates. The related pairs comprised two individuals who were each other’s siblings, whereas the unrelated pairs involved two individuals organized in such a way that they were not co-twins of the other person in the pairing. As the unrelated pairs consisted of two individuals who were not co-twins, they were more diverse than the related pairs. Thus, if it was found that the former made more accurate collective judgments than the latter, this would corroborate the hypothesis that diversity (genetic, environmental, or both) contributes to the accuracy of collective judgments.
[ie. the participants all predict independently, so there are no interaction or deference or groupthink effects]
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