Evidence for a global categorical representation of humans by young infants.

The representation of pictorial exemplars of humans by young infants was examined. Experiments 1B and 2 demonstrated an asymmetry with respect to the exclusivity of the categorical representations formed by 3- and 4-month-olds for humans and non-human animal species. The categorical representation for humans included novel humans, horses, cats, and fish, but excluded cars; the categorical representation for horses included novel horses, but excluded humans, fish, and cars. Experiment 2 also showed that the categorical representation for humans included exemplar information, whereas the categorical representation for non-human animal species was based on summary information. The asymmetry in categorization of human versus non-human animal species did not extend to the presumed more basic process of discrimination of individual humans versus non-human animals (Experiment 3). The findings suggest that a broad categorical representation of humans may be a cognitive reference point (or region) for young infants.