Any member of a species with a complex social organisation needs to be able to recognise other individuals, in order to be able to interact with them in different ways. For humans, the face is especially important to recognition. In addition, a wealth of social information other than identity can be derived from the face. We use this to infer moods and feelings, to regulate social interaction through eye contact and facial gestures, to support speech comprehension by lip-reading (even people with normal hearing do this


without realising it), to determine age and sex, and to attribute characteristics on the basis of social stereotypes.