Kin recognition, also called kin detection, is an organism's ability to distinguish between close genetic kin and non-kin. In evolutionary biology and evolutionary psychology, such an ability is presumed to have evolved for inbreeding avoidance. While a 2021 meta-analysis of research across 88 diploid species found that animals rarely avoid inbreeding, avoidance is more common in species with developmental co-residence since the latter is a proxy for kin recognition.
An additional adaptive function sometimes posited for kin recognition is a role in kin selection. There is debate over this, since in strict theoretical terms kin recognition is not necessary for kin selection or the cooperation associated with it. Rather, social behaviour can emerge by kin selection in the demographic conditions of 'viscous populations' with organisms interacting in their natal context, without active kin discrimination, since social participants by default typically share recent common origin. Since kin selection theory emerged, much research has been produced investigating the possible role of kin recognition mechanisms in mediating altruism. Some researchers suggest that, taken as a whole, active powers of recognition play a negligible role in mediating social cooperation relative to less elaborate cue-based and context-based mechanisms, such as familiarity and imprinting, whereas other researchers argue that specialized kin recognition mechanisms, such as phenotype matching, are widespread in facilitating nepotism.