A tale of two cases: Emotion and affective prosody after hemispherectomy

The neurological substrate for affective prosody and the developmental relationship between prosody and emotion are not fully understood. Therefore, this dissertation investigates emotion and affective prosody in two high-functioning hemispherectomized adolescent boys, one missing his left and one missing his right hemisphere.; This dissertation is comprised of three articles, comparing production and reception of emotion and prosody for the two hemispherectomized boys and a sample of normal comparison boys. The first article examines the abilities of these boys to discriminate pitch cues to affective and linguistic prosody and to make use of these cues to understand the sarcasm sincerity distinction, and analyzes the participants' social, cognitive and emotional strategies in explaining their answers. My main finding is that both hemispherectomized boys are competent at recognizing sarcasm and sincerity by tone of voice, but that the left-hemispherectomized boy relies heavily on connections between tone and emotion, while the right-hemispherectomized boy relies heavily on something akin to "pseudo-grammatical" categorization of tone, with little reference to emotion.; The second article explores the hemispherectomized boys' use of intonation in their spontaneous speech. My main conclusion is that both boys defy neuropsychological prediction to produce more intonation than their peers in the same speech context (i.e. both boys are somewhat hyperprosodic). In addition, both hemispherectomized boys seem less systematic in the ways they assign intonation to utterances, suggesting a need for both hemispheres to accomplish this task with precision. The findings suggest a role for the right hemisphere in producing affective intonation, for the left hemisphere in modulating the right hemisphere's intonational production, and, more speculatively, for an integration between the hemispheres in matching appropriate amounts of intonation to the conversational purpose of an utterance.; The third article provides a narrative account of the work on prosody and emotion, from which I formulate a theory of developmental plasticity and draw educational implications. The findings suggest that both boys are compensating by adapting their processing of affective prosody into a new kind of processing that better suits their respective neuropsychological strengths, rather than by adapting their remaining brain tissue to act as the missing hemisphere would have.