Behavior Genetics

, Volume 14, Issue 3, pp 179-193

First online:

Genetic similarity theory: Beyond kin selection

  • J. Philippe RushtonAffiliated withDepartment of Psychology, University of Western Ontario
  • , Robin J. H. RussellAffiliated withDepartment of Psychology, University of London Goldsmiths' College
  • , Pamela A. WellsAffiliated withDepartment of Psychology, University of London Goldsmiths' College

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We present genetic similarity theory (GST), which incorporates the kin-selection theory of altruism under a more general principle. GST states that a gene ensures its own survival by acting so as to bring about the reproduction ofany organism in which copies of itself are to be found. Rather than behaving altruistically only toward kin, organisms are able to detect other genetically similar organisms and to exhibit favoritism and protective behavior toward these “strangers,” as well as toward their own relatives. In order to pursue this general strategy, an organism must, in effect, be able to detect copies of its genes in other organisms. We order several data sets with this theory including (a) kin recognition studies in animals raised apart, (b) assortative mating, (c) intrafamilial relations, (d) human friendship and altruism, and (e) ethnic nepotism. We discuss a strong and a weak version of GST and offer some predictions for future research.

Key Words

altruism assortative mating friendship genetic similarity theory inclusive fitness kin recognition kin-selection theory personality sociobiology