Automatic and effortful processing of emotional intonation after right or left hemisphere brain damage

This study assessed the effects of unilateral right (RHD) or left hemisphere brain damage (LHD) on the knowledge and processing of emotional information imparted by vocal intonation. Semantically neutral statements that conveyed a mood through prosody were used as targets in a mood priming task. These targets were preceded by story primes. The events described in the primes were either congruent with the mood conveyed by the intonation of a target phrase, incongruent with target mood, or emotionally neutral. Prime-target pairs were presented in two attention conditions designed to favor either relatively automatic or effortful mental processing. Response time (RT) data were recorded for accurate judgments of target moods. In the automatic condition, there were no qualitative differences between RHD, LHD, or normally aging control subjects. In the effortful condition, RTs for each group were similarly improved by congruent primes (relative to neutral primes), but RHD subjects were disproportionately slower when targets were preceded by incongruent primes. Results indicate that brain-damaged adults retain knowledge of emotional meanings, and use that knowledge to facilitate effective interpretations in some circumstances. Demands for emotional inference revision were not exclusively responsible for RHD adults' poor performance with incongruent primes, as they successfully revised initial predictions in other conditions. Rather, these subjects' difficulties arose when increased processing demands converged with decreased availability of mental resources. These findings are integrated with those from a related study of lexical metaphor, and are interpreted within a cognitive resource framework.