Etymology

From a hypothetical example used in Richard Dawkins' book The Selfish Gene (1976), whereby a person with a green beard acts altruistically towards other people with green beards.

Proper noun

green-beard effectCategory:English lemmas#GREENBEARDEFFECTCategory:English proper nouns#GREENBEARDEFFECTCategory:English uncountable nouns#GREENBEARDEFFECTCategory:English multiword terms#GREENBEARDEFFECTCategory:English entries with incorrect language header#GREENBEARDEFFECTCategory:Pages with entries#GREEN-BEARD%20EFFECTCategory:Pages with 1 entry#GREEN-BEARD%20EFFECT

1. (biologyCategory:en:Biology#GREENBEARDEFFECT) A hypothesis in evolutionary biology that explains selective altruism among individuals of a species, involving preferential treatment of individuals with certain characteristics.