Is visual reference necessary? Contributions of facial versus vocal cues in 12-month-olds' social referencing behavior.

To examine the influences of facial versus vocal cues on infants' behavior in a potentially threatening situation, 12-month-olds on a visual cliff received positive facial-only, vocal-only, or both facial and vocal cues from mothers. Infants' crossing times and looks to mother were assessed. Infants crossed the cliff faster with multimodal and vocal than with facial cues, and looked more to mother in the Face Plus Voice compared to the Voice Only condition. The findings suggest that vocal cues, even without a visual reference, are more potent than facial cues in guiding infants' behavior. The discussion focuses on the meaning of infants' looks and the role of voice in development of social cognition.