Human Emotional Vocalizations Can Develop In The Absence Of Auditory Learning

Are emotional expressions shaped by specialized innate mechanisms that guide learning, or do they develop exclusively from learning without innate preparedness? Here we test whether nonverbal affective vocalisations produced by bilaterally congenitally deaf adults contain emotional information that is recognisable to naive listeners. Because these deaf individuals have had no opportunity for auditory learning, the presence of such an association would imply that mappings between emotions and vocalizations are buffered against the absence of input that is typically important for their development and thus at least partly innate. We recorded nonverbal vocalizations expressing 9 emotions from 8 deaf individuals (435 tokens) and 8 matched hearing individuals (536 tokens). These vocalizations were submitted to an acoustic analysis and used in a recognition study in which naive listeners (n = 812) made forced-choice judgments. Our results show that naive listeners can reliably infer many emotional states from nonverbal vocalizations produced by deaf individuals. In particular, deaf vocalizations of fear, disgust, sadness, amusement, sensual pleasure, surprise, and relief were recognized at better-than-chance levels, whereas anger and achievement/triumph vocalizations were not. Differences were found on most acoustic features of the vocalizations produced by deaf as compared with hearing individuals. Our results suggest that there is an innate component to the associations between human emotions and vocalizations.