Infants' attention bias to faces as an early marker of social development.

Infants have a strong tendency to look at faces. We examined individual variations in this attentional bias in 7-month-old infants by using a face-distractor competition paradigm and tested in a longitudinal sample whether these variations were associated with outcomes reflecting social behavior at 24 and 48 months of age (i.e., spontaneous helping, emotion understanding, mentalizing, and callous-unemotional traits; N = 100-138). The results showed a robust and distinct attention bias to faces at 7 months, particularly when faces were displaying a fearful expression. This bias declined between 7 and 24 months and there were no significant correlations in attention dwell times between 7 and 24 months of age. Variations in attention to faces at 7 months were not associated with emotion understanding or mentalizing abilities at 48 months of age, but increased attention to faces at 7 months (regardless of facial expression) was related to more frequent helping responses at 24 months and reduced callous-unemotional traits at 48 months of age. Thus, while the results fail to associate infants' face bias with later-emerging emotion understanding and mentalizing capacities, they are consistent with a model whereby increased attention to faces in infancy is linked with the development of affective empathy and responsivity to others' needs.