How to recognize a face
Even the monkeys recognize each other from the face and do not use memory but some specialized neurons. With a process that according to some US scientists is very similar to ours.

Monkeys can also recognize faces

Recognizing someone is a very spontaneous action that we do almost without realizing. And according to some estimates, we are able to recognize thousands of faces .
But how is it possible to "memorize" so much data? Some scientists from the National Health Institute of Bethesda in Maryland (USA) asked about this, studying the recognition system of some monkeys, whose functioning is very similar to the human one.
Face to face
In the part of the brain called "inferotemporal cortex" there are a series of neurons "involved" in the recognition of faces. But their operation is still unclear.
Scientists observed the brains of two monkeys (Macaca mulatta) as they were shown a series of photos of human faces. Then they slightly modified them and showed them back to the animals. And they discovered that the "recognition neurons" of the monkeys were activated especially in the face of even slight differences between one image and another.
The differences that make the difference
The study, according to the scientists, shows that we do not store the physical features of all the people we know in our memory and then recall them when we encounter one. But, as the monkeys do, we probably proceed by comparison. At the head we have a generic "archive" of the most common and frequent somatic traits, when we see a face we compare it to the statistical average we have in mind, immediately noticing the differences, even the most subtle. And it is precisely the differences that determine that face for us and make us recognize it.
In other words we recognize a person with characteristics that he does not have in common with the others and we manage to do it in a fraction of a second. And without "weighing down" the memory.
(News updated 6 July 2006)