Presentation

Haining Cui¹, Hyeonjeong Jeong¹, Marc D. Pell², Motoaki Sugiura¹; ¹Tohoku University, ²McGill University

Emerging sociolinguistic studies show that when listeners rate utterances varying in prosodic impressions of politeness (e.g., level of sincerity, friendliness), foreign-accented speech tends to be assessed as carrying less emotive meaning than native speech. These perceptual findings suggest that hearing a foreign accent alters the listener’s ability to encode the affective-prosodic meaning of speech acts. Although neuroimaging research has well documented the critical role of temporal lobes in the perception of accented voice, search for voice-related memory, and encoding of socio-affective vocal cues, it remains unclear to what extent foreign accents affect brain responses associated with processing affective-prosodic speech. To clarify this issue, we created a task containing Japanese honorific utterances varying in Accent [Native (N) vs. Foreign (F)] and Prosodic impression [Sincere (S) vs. Insincere (I)]. During fMRI scanning, 29 participants were instructed to listen to the stimuli utterances, to ensure attention, they were asked to judge whether or not a word had appeared in the previous utterance. In addition, to explore whether individual differences in foreign accent familiarity affect the neural process of encoding affective-prosodic meaning, all listeners filled out an accent rating scale after fMRI scanning. Based on previous perception and neuroimaging findings, we expected that comprehending the affective-prosodic meaning of sincerity would depend on the perception of accent differences. Such an effect would engage brain regions sensitive to accent-prosodic analysis. We also expected that individual differences in foreign accent familiarity would mediate brain responses associated with the retrieval of voice-related memory (e.g., recognizing familiar speakers) during utterance comprehension. Brain imaging data were analyzed using SPM 12 software (cluster level p < 0.05 FWE corrected). Based on our hypothesis, we focused on the interaction effect between the type of accent and prosodic impression ([NI vs. NS] > [FI vs. FS]) in the whole-brain group-level analysis. Moreover, we performed a single regression analysis at the whole-brain level for the foreign-accented conditions (FI, FS, and [FI vs. FS]) with the foreign accent familiarity score of each participant. Two major findings emerged. First, the interaction contrast ([NS > NI] > [FS > FI]) elicited a significant response in the right posterior superior temporal cortex. Second, we found that activity in the right medial temporal region was positively correlated with perceived accent familiarity for utterances produced in the foreign accent ([FI > FS] contrast, p < 0.001 uncorrected). Taken together, the interaction of impressions formed from a speaker’s accent and their mode of prosodic expression provides novel evidence of how the right superior temporal cortex integrates different types of socio-affective vocal cues during speech comprehension. Moreover, the correlation finding suggests that individual differences in accent familiarity modulate the cortical response when processing affective-prosodic meanings expressed by a foreign-language speaker; this process may be mediated by the brain structures associated with the recognition of familiar speakers.

Topic Areas: Prosody, Meaning: Discourse and Pragmatics