Emotion in Animals - Evidence - Specific Evidence - Primates

Primates

Primates and in particular great apes are candidates for highly developed capabilities for empathy and theories of mind. Great apes have highly complex social systems. Young apes and their mothers have very strong bonds of attachment. Often when a baby chimpanzee or gorilla dies, the mother will carry the body around for several days. Jane Goodall has described chimpanzees as exhibiting mournful behavior. See notably the example of the gorilla Koko, who expressed sadness over the death of her pet cat, All Ball.

Beyond such anecdotal evidence, strong support for empathetic reactions has come from studies of rhesus macaques. In studies by Wechkin et al. and Masserman et al., these macaques refused to pull a chain that delivered food to themselves if doing so shocked a companion. This inhibition to hurt another was more pronounced between familiar than unfamiliar macaques, a finding similar to that of empathy in humans.

Moreover, there has been a good deal of research conducted on consolation behavior in chimpanzees. De Waal and Aureli found that third-party contacts attempt to relieve the distress of contact participants by consoling (e.g. making contact, embracing, grooming, etc.) recipients of aggression, especially those that have faced more intense aggression. Interestingly, researchers were unable to replicate these results using the same observation protocol in studies of monkeys, demonstrating a possible difference in empathy between monkeys and apes.

Finally, some studies have examined emotional processing in the great apes. Specifically, chimpanzees were shown video clips of emotionally charged scenes, such as a detested veterinary procedure or a favorite food, and then were required to match these scenes with one of two species-specific facial expressions: “happy” (a play-face) or “sad” (a teeth-baring expression seen in frustration or after defeat). The chimpanzees correctly matched the clips to the facial expressions that shared their meaning, demonstrating that they understand the emotional significance of their facial expressions. Measures of peripheral skin temperature confirmed that the video clips emotionally affected the chimpanzees.