Gaze following and joint attention in rhesus monkeys (Macaca mulatta)

Gaze and attention direction provide important sources of social information for primates. Behavioral studies show that chimpanzees spontaneously follow human gaze direction. By contrast, non-ape species such as macaques fail to follow gaze cues. The authors investigated the reactions of rhesus macaques (Macaca mulatta) to attention cues of conspecifics. Two subjects were presented with videotaped images of a stimulus monkey with its attention directed to 1 of 2 identical objects. Analysis of eye movements revealed that both subjects inspected the target (object or position attended by the stimulus monkey) more often than the distractor (nonattended object or position). These results provide evidence that rhesus monkeys follow gaze and use the attention cues of other monkeys to orient their own attention to objects.