Genetic evidence for multiple biological mechanisms underlying in-group favoritism.
In-group favoritism is ubiquitous and associated with intergroup conflict, yet is little understood from a biological perspective. A fundamental question regarding the structure of favoritism is whether it is inflexibly directed toward distinct, "essentialist" categories, such as ethnicity and race, or is deployed in a context-sensitive manner. In this article, we report the first study (to our knowledge) of the genetic and environmental structure of in-group favoritism in the religious, ethnic, and racial domains. We contrasted a model of favoritism based on a single domain-general central affiliation mechanism (CAM) with a model in which each domain was influenced by specific mechanisms. In a series of multivariate analyses, utilizing a large, representative sample of twins, models containing only the CAM or essentialist domains fit the data poorly. The best-fitting model revealed that a biological mechanism facilitates affiliation with arbitrary groups and exists alongside essentialist systems that evolved to process salient cues, such as shared beliefs and ancestry.
Lewis
Gary J
GJ
Department of Psychology, 7 George Square, University of Edinburgh, Edinburgh EH8 9JZ, United Kingdom. glewis1@gmail.com
Bates
Timothy C
TC
D000328:Adult; D002755:Choice Behavior; D003463:Cues; D003466:Cultural Characteristics; D005006:Ethnicity / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D008393:Marriage; D008875:Middle Aged; D008960:Models, Psychological; D010641:Phenotype; D012069:Religion and Psychology; D012931:Social Environment; D012933:Social Identification; D012945:Social Values; D014429:Twins, Dizygotic / Q000235:genetics*; D014430:Twins, Monozygotic / Q000235:genetics*