Normal recognition of famous voices in developmental prosopagnosia

Abstract

Developmental prosopagnosia (DP) is a condition characterised by lifelong face recognition difficulties. Recent neuroimaging findings suggest that DP may be associated with aberrant structure and function in multimodal regions of cortex implicated in the processing of both facial and vocal identity. These findings suggest that both facial and vocal recognition may be impaired in DP. To test this possibility, we compared the performance of 22 DPs and a group of typical controls, on closely matched tasks that assessed famous face and famous voice recognition ability. As expected, the DPs showed severe impairment on the face recognition task, relative to typical controls. In contrast, however, the DPs and controls identified a similar number of voices. Despite evidence of interactions between facial and vocal processing, these findings suggest some degree of dissociation between the two processing pathways, whereby one can be impaired while the other develops typically. A possible explanation for this dissociation in DP could be that the deficit originates in the early perceptual encoding of face structure, rather than at later, post-perceptual stages of face identity processing, which may be more likely to involve interactions with other modalities.

Figure 1

Performance in the famous face and voice recognition tasks. (a) Mean proportion of faces and voices that were correctly identified by the DP and control groups. (b) Identification accuracies for individual subjects. (c) Mean proportion of faces and voices that were classified as familiar by each group. (d) Familiarity scores for individual subjects. Error bars show standard errors.

Figure 2

Ratings of perceived exposure frequency for the celebrities presented in the face and voice recognition tasks. (a) Mean ratings for faces and voices in the DP and control groups. (b) Individual subject ratings. Error bars show standard errors.

Figure 3

Scores on the voice recognition questionnaire. (a) Mean scores for the DP and control groups. (b) Individual subject scores. Higher scores indicate poorer perceived voice recognition ability.