Being able to tell human faces apart is a skill that almost every person has, although some are far better at it than others. But a new study says that this is not just a skill that humans have. Even fish can do it.
Following up on research studying different species'(物种)abilities to recognize human laces(sheep, dogs, cows, horses, and birds have all been tried),the researchers from the University of Oxford decided to pick an animal that does not have an evolved neocortex, the part of the brain that processes sight and sounds, and doesn't have a close relationship with humans. That way, there would be no reason why these test subjects(实验对象)would have a past history of identifying human faces.
So they picked the archerfish, a reef fish variety that shoots water into the air to knock its prey(猎物)out of the sky. They used this adaptation to have the fish spray water at a face on a monitor hanging over their tanks for a reward. Most of the fish were able to pick apart their learned face, even when colors were taken away.
This study gives more support to the assumption that distinguishing between faces is not just a skill that big-brained organisms are born with. It is possible that a good percentage of recognizing faces is learned over time. The development of neocortex may contribute only to quickly processing a large number of faces in varying situations.
But more work needs to be conducted to find a deeper link to this possible learned behavior. The sample size of this study was very small-only eight fish were used altogether. Also, the faces displayed were only white, female faces from a German database, shown in a front view, with no expressions. Other animal trials have shown that some species, like pigeons, respond more to different angles and varied expressions.
