To young infants who have not yet developed the capacity for language, the human face holds particular significance. After all, it is the face that conveys a range of nonverbal information, including identity, gender, age, affective state, and possibly intention (e.g., pursing of the lips suggestive of a forthcoming kiss). Although this visual information is also important to adults, they are less dependent on it since, unlike infants, they are able to take advantage of information conveyed through language.

Of the many types of information that the face transmits to the infant or young child, facial expressions may be the most important. Darwin (1896) first brought this to attention by suggesting that the display and recognition of facial expressions may represent an adaptation that serves the purpose of communication and survival. For example, an infant's recognition of an angry expression displayed by a stranger could facilitate a crying response, which will in turn bring the caregiver to protect the infant. Similarly, an infant's recognition of a happy expression displayed by the caregiver could facilitate the expression of happiness in the infant, which could contribute to the development of the attachment relationship (Bowlby, 1969).

How does the ability to recognize expressions develop?

Biological contributions

One factor that may contribute to the development of the ability to recognize expressions is development of the neural systems involved in recognition.