Chimpanzees may act as if they were grooming an injured individual or helping a trapped individual, which appears to indicate empathy for others.In the case of humans, it is known that one feels as if one is experiencing pain due to the injury or pain of another person.However, it was unclear whether chimpanzees would react emotionally to the injuries of others.

　This time, we conducted an experiment on 6 chimpanzees living in Kumamoto Sanctuary, Kyoto University.The chimpanzee was shown eight image pairs with pictures of injured and non-injured individuals.When the line of sight was measured using a line-of-sight measuring device, it took longer to see the photograph of the injured individual.

　Furthermore, regarding the emotional response, changes in skin temperature were investigated using infrared thermography that does not affect the chimpanzee response for non-contact measurement.When a human experimenter injured his hand with a cut (reproduced with make-up) in front of his eyes, the skin temperature at the tip of his nose dropped significantly in 6 out of 3 individuals in the injured scene.However, there was no big difference when a human accidentally stabbed a needle in his thumb.Unlike humans, there is no opportunity to use needles.　　　

　How human empathy has evolved with these achievements, suggesting that chimpanzees, the animals that are evolutionarily closest to humans, pay attention to the injuries of others and react emotionally. It is expected that understanding will progress.

Paper information:[Animal Cognition] Spontaneous attention and psycho-physiological responses to others' injury in chimpanzees