Emotion processing in congenital amusia: the deficits do not generalize to written emotion words.

Congenital amusia is a lifelong impairment in musical ability. Individuals with amusia are found to show reduced sensitivity to emotion recognition in speech prosody and silent facial expressions, implying a possible cross-modal emotion-processing deficit. However, it is not clear whether the observed deficits are primarily confined to socio-emotional contexts, where visual cues (facial expression) often co-occur with auditory cues (emotion prosody) to express intended emotions, or extend to linguistic emotion processing. In order to better understand the underlying deficiency mechanism of emotion processing in individuals with amusia, we examined whether reduced sensitivity to emotional processing extends to the recognition of emotion category and valence of written words in individuals with amusia. Twenty Cantonese speakers with amusia and 17 controls were tested in three experiments: (1) emotion prosody rating, in which participants rated how much each spoken sentence was expressed in each of the four emotions on 7-point rating scales; (2) written word emotion recognition, in which participants recognized the emotion of written emotion words; and (3) written word valence judgment, in which participants judged the valence of written words. Results showed that participants with amusia preformed significantly less accurately than controls in emotion prosody recognition; in contrast, the two groups showed no significant difference in accuracy rates in both written word tasks (emotion recognition and valence judgment). The results indicate that the impairment of individuals with amusia in emotion processing may not generalize to linguistic emotion processing in written words, implying that the emotion deficit is likely to be restricted to socio-emotional contexts in individuals with amusia.