Do blind and sighted persons differ in how they process social information from the voice?
The human voice plays an important function in social communication beyond language. Nonverbal parameters such as voice pitch and vocal tract resonances can reliably indicate a speaker’s age, sex, and body size, and are associated with various psychosocial traits. Although listeners are highly consistent, systematic, and often accurate in their voice-based assessments of other people, the mechanisms that drive this capacity remain unknown. In a series of experiments on congenitally blind, early-blind, late-blind and sighted adults, we tested whether voice-based assessments of trustworthiness, warmth and competence develop in the absence of visual experience, and whether vision is necessary to calibrate accurate estimates of body size from the voice. The results of this research convincingly suggest that vision is not a necessary prerequisite for stereotypical or accurate voice perception. This capacity may be present at birth or may be learned via broader cross-modal correspondences. Our findings further suggest that, although blind persons appear to possess ‘supra-normal’ auditory processing capabilities for low-level tasks such as pitch discrimination or for the processing of linguistic information, these advantages may not generalize to the processing of nonverbal, and highly socially relevant vocal cues.