A group of Osaka City University and others revealed that fish, like humans and chimpanzees, first look at the other person's face and then frequently look at the other person's face.
Humans and chimpanzees identify their opponents by their faces, and when they meet, they first see their faces and then often.There were no studies investigating this facial cognitive habit in animals other than primates, but this time, the partner individual is also a species of cichlid fish that is known to identify the partner based on the pattern of the face. I expected to see my face first in order to quickly recognize who I was, and tested that hypothesis.
Since "eye tracking", which is usually used to track the location and movement of the line of sight, cannot be used underwater, the puller should approach something that should be noted, aim the body axis at the target, and stand still for a while to binocular vision. We devised a method to determine the object of interest by confirming the above and extending the body axis when viewing with both eyes.
Using this method, photographs of the same species and other species of fish (transformers) were shown to the puller, and how much the face, torso, and tail were binocularly viewed was determined.As a result, it was found that regardless of the left-right orientation of the photograph, he first looked at his face and then frequently looked at his face.I didn't look much at the torso and tail, and the result was the same even with a transformer with a pattern on the whole body.
From the above, it is considered that the puller can see the face the moment the other person comes into view, pay attention to the face first, and make an important recognition as to who the other person is or whether it is a stranger.In the case of humans and monkeys, looking at the face many times after that is done to understand what the other individual is paying attention to, but it is possible that fish are also doing it for the same purpose. Is enough.
It can be said that this discovery shows the commonality in face recognition between fish, which have been regarded as the extremes of vertebrates, and humans and primates.
Paper information:[Scientific Reports] Fish focus primarily on the faces of other fish
