Visual cues for attention following in rhesus monkeys

It is now well established that great apes follow human gaze direction. Des pite physiological evidence showing cells in macaque temporal cortex sensit ive to direction of eye gaze, there has been little evidence in non-ape spe cies of similar abilities. The aim of this study was to investigate, at a b ehavioural level, whether monkeys can use static gaze, head, and body cues of conspecifics to interpret the direction of attention of others. We recor ded the looking behaviour of 2 rhesus monkeys elicited by the presentation of photographs of conspecifics directing their attention in space. With pho tos of monkey stimuli whose head and body were oriented in different or sim ilar directions, we found that the head but not the body was used by the mo nkey subjects to orient their own attention. With photos of monkey faces or iented to the camera while gaze was averted left, right, up or down, we dem onstrated that monkeys are able to spontaneously follow gaze of conspecific s. With photos of monkey heads oriented 45 degrees to the right or left, at tention following was stronger when the gaze direction was consistent with the head orientation than when the eyes were directed towards the observer. Our studies show that both head orientation and eye gaze influence the obs erver's orienting responses.