COGNITIVE EVOLUTION IN PRIMATES - EVIDENCE FROM TACTICAL DECEPTION

Through the compilation of an extensive catalogue of tactical deception in non-human primates, incorporating evidence contributed by many primatologists and covering all major taxa, it has become feasible to initiate quantitative comparisons between taxa, having adjusted for variations in the extent to which they have been studied. Papio and (especially) Pan show disproportionately high levels of tactical deception, whereas strepsirhines have not yielded any evidence of deception at all. Some records indicate sophisticated social cognition. Records implying the attribution of intentional states to others are associated with the great apes, particularly Pan, whereas the ability to compute the visual perspective of others conforms to the distribution of tactical deception across the anthropoids in general. These differences are used to infer critical changes in the course of primate social evolution. Changes appear to be due more to savannah dwelling and neocortical enlargement, itself linked to increased body size, than to a particular social structure.