The everyday ability in which we most clearly express our individuality is speech. It also marks us off from other species. Yet even our wordless communication illustrates quite well how different we are from animals. I now return to the story begun in Chapter 4.

Communication without words

Some forms of human communication, especially the signals of infancy, resemble those of animals in being distinct patterns common to our whole species. They may be sounds, such as an infant's cry, sights such as a smile, or even odors, though we know less about them. The most fully studied of our non-verbal signals are those that we can see. We use facial expressions, postures and gestures to convey attitudes, emotions and intentions, often unconsciously. The whites of our eyes and our pink lips are distinctive features of human beings and help us to convey information to others: we can instantly tell in what direction a person is looking, and the understanding of speech and of facial expression is aided by watching lip movements. Still more important, the muscles of expression – those around our eyes, nose and lips – give the human face an exceptional mobility which is already evident at birth: a newborn infant can indicate disgust at an unpleasant taste. By the age of 36 hours an infant can imitate the facial expressions of an adult.