Researchers at the Universities of Bristol, Florence, and Western Australia have found that kids with autism don't adapt as readily to unfamiliar faces – a finding that may help explain some of the social problems that confront people with the disorder.

Elizabeth Pellicano of the University of Bristol who took part in the study explained why this finding was significant.

“The faces we see in the world seem to be unconsciously coded in the brain as points in a ‘face-space’. In the middle of that space is the average, or most typical, face, with more distinctive faces lying toward the periphery. Those more distinctive faces are easier to recognize than ones that are closer to average,” she said.

When people with normal abilities see a face, their brains automatically locate this new face in face-space on the basis of its deviations from the average, with the precise characteristics of what constitutes an average face changing based on the experiences of looking at other people.

This flexibility stems from a phenomenon known as the “face identity aftereffect,” in which looking at a particular face even briefly biases perception toward people who have the “opposite identity”.

For example, upon seeing a person with thicker-than-average lips, the observer’s idea of the typical face accordingly develops somewhat plumper lips. As a result, thinner-lipped people become more distinctive than they would have been before because their lips now differ more from the “norm.”