Infants' perception of dynamic affective expressions: do infants distinguish specific expressions?

Seven-month-old infants' perception of positive (happy, interested) and negative (angry, sad) affective expressions was investigated using a preferential looking procedure (n = 20 in each of 6 conditions). The infants saw two videotaped facial expressions and heard a single vocal expression concordant with one of the facial expressions. The voice on the soundtrack was played 5 s out of synchrony with the ongoing affective visual display. Infants participated in one of six conditions (all possible pairs of the four expressive events). Infants' visual fixations to the affectively concordant and affectively discordant displays were recorded. Infants looked longer at the affectively concordant displays than at the affectively discordant displays in all conditions except the happy/sad and interested/sad conditions. For these two comparisons, facial discrimination was demonstrated by the infants' preferential looking at happy and interested expressions compared to the sad expression. Thus, 7-month-old infants discriminate among happy, interested, angry, and sad expressions, demonstrating differentiation among specific, dynamic expressions. The results are discussed in terms of the information specifying facial and vocal affect and the possible role of familiarity in learning to differentiate among affective expressions during infancy.