Mental representations in the recognition of conspecific individuals.

Individual recognition requires that animals form mental representations of the properties of conspecifics as well as of the identity of particular conspecifics. Gallistel has defined representations as a precise correspondence (an isomorphism) between objects and relations in the environment and structure-preserving systems in the animal's brain. Research on the neural recognition of individual conspecifics is examined to check whether the results satisfy part of Gallistel's definition. Mental representations are also discussed with reference to concept-discrimination experiments which have demonstrated individual recognition using slides of conspecifics. Finally, a simple set-theoretical model is presented to describe recognition of the idiosyncratic properties of conspecifics.