Facial mimicry in the congenitally blind.

Imitation is one of the core building blocks of human social cognition, supporting capacities as diverse as empathy, social learning, and knowledge acquisition. Newborns' ability to match others' motor acts, while quite limited initially, drastically improves during the first months of development. Of notable importance to human sociality is our tendency to rapidly mimic facial expressions of emotion. Facial mimicry develops around six months of age, but because of its late emergence, the factors supporting its development are relatively unknown. One possibility is that the development of facial mimicry depends on seeing emotional imitative behavior in others. Alternatively, the drive to imitate facial expressions of emotion may be independent of visual learning and be supported by modality-general processes. Here we report evidence for the latter, by showing that congenitally blind participants facially imitate smiles heard in speech, despite having never seen a facial expression.