The perception of personal identity in speech: Evidence from the perception of twins’ speech

Three experiments studied the perception of speech produced by female twins (5 MZ, 1 DZ) ranging in age from 20 to 67. The experiments were designed to discover whether listeners could detect differences between twins, and to explore listeners’ perceptual representations of talkers. Because identical twins have virtually identical vocal tracts and the twins in this study grew up together in the same home, they serve as a unique control population for studies of the perception of personal identity. The results showed that listeners’ sensitivity to twin differences was greater than chance and stable over changes in experimental conditions. Analysis of the perceptual space for talkers showed that the difference between identical twins was in some cases as large as the difference between unrelated talkers. The dimensions of the perceptual space were related to age and dialect, and the distance between twins in the perceptual space was not related to age. PACS numbers: 43.71.B, 43.70.G Johnson & Azara 2