Recognition systems and biological organization: The perception component of social recognition

Recognition of conspecifics is necessary for differential treatment of individuals in a variety of social contexts, such as territory establishment and defense, dominance hierarchies, reciprocal altruism, mate choice, parent-offspring interactions and nepotistic contexts, to name a few. Here I first review various categories of perceptual mechanisms of social discrimination, focusing largely on the extensive literature on the perception component of kin recognition, although the ideas presented here can and have been used for analyses of recognition at many levels of social organization. I then discuss a range of recognition mechanisms observed in a model species, Belding's ground squirrels, and how socio-ecological factors influence the development and expression of each mechanism. Finally, I address several theoretical and empirical controversies in the kin-recognition literature which pertain to the perceptual component of recognition, as well as areas in need of additional investigation.