Affective facial expression in infants with focal brain damage.

Children are fluent affective communicators by their first birthday. The development of affective facial expression in infants with focal brain damage thus provides a promising context in which to investigate the developing neural substrates of emotions. We examined both positive and negative affective expression in 12 infants (6-24 months) with pre- or perinatal unilateral focal brain damage (6RHD and 6LHD) and their age- and gender-matched controls. Infants were videotaped in free and semi-structured tasks. Interactions were microanalytically coded, including the use of FACS. Both normal and babies with posterior LHD exhibited the full range of appropriate affective expressions. In contrast, infants with posterior RHD showed marked affective impairment to positive, but not to negative simulation.