Monkeys recognise each other by comparing faces to an average stored in their brains, not by memorising what every individual looks like, scientists have said. And that probably goes for people, too, explaining how faces can be recognised in a fraction of a second, a research in Nature reported.
The scientists found that a monkey's brain keeps a statistical average of the faces it has seen and uses it as a basis for comparison. "When it sees a new face it compares it to this average and then it remarks upon the differences...
And that is how the face is seen," said David Leopold, of the National Institute of Mental Health in Bethesda, Maryland.
"What we found is that the neurons in a part of the monkey's brain respond in a way that is extremely sensitive to the small differences in information between faces of different identities," said Leopold.
The activity of the neurons was monitored as the monkeys were shown an average face of a person and as it was artificially morphed. In psychological tests, humans identify faces in much the same way.
Researchers believe this aspect of the visual recognition system is similar in both species.