The recognition of facial expressions in the first two years of life: mechanisms of development.

In recent years the infant's ability to recognize facial expressions of emotion has attracted considerable attention from developmental psychologists. The rationale guiding much of this research has been that this ability plays an important role in later socioemotional development. In the present article, the research relating to this topic is reviewed and synthesized. It is concluded that the recognition of facial expressions develops slowly over the first 2 years of life, and that even at the end of the second year the infant's understanding of facial expressions is still quite rudimentary. Following this review is a discussion of 2 unresolved issues regarding the development of this ability. 1 issue relates to the biological/experimental basis on which the ability to recognize facial expressions develops. Research with primates is brought to bear on this point, and useful analogues with human infants are sought. From this research it is suggested that a component of the ability to recognize facial expressions is unlearned, although experience of some as yet undetermined nature affects this biological readiness. The second issue relates to the possible neurological mechanisms that mediate this ability. Research with primates, normal adults, and brain damaged adults is used to support the speculation that a posterior region of the right hemisphere is responsible for mediating the recognition of facial expressions.