Specificity of gaze-following in young chimpanzees

The development of gaze-following (or joint visual attention) allows human infants to orient to the same object. or event to which another person is looking. The development of the ability undergoes elaborations between 6 and 18 months, with older infants displaying the ability to (a) track gaze in response to eye movement alone, (b) look into space outside of their immediate visual field, and (c) precisely localize the exact object at which another is looking. Chimpanzees also exhibit gaze-following, but certain aspects of the specificity of this ability remain unclear. Seven pre-adolescent chimpanzees were used to replicate and extend a previous demonstration of gaze-following and to test the hypothesis that chimpanzees (like 18-month-old human infants) are capable of determining the specific location in space behind them into which another looks. The results strongly support the hypothesis, and suggest extensive commonality in the behavioural manifestations of gaze-following in the two species. Whether chimpanzees develop a parallel understanding of the mental state of attention behind gaze remains less clear.