Poster D67, Wednesday, August 21, 2019, 5:15 – 7:00 pm, Restaurant Hall
Neural indices of voice stream segregation in monolinguals and bilinguals
Melissa Baker1, Clara Liberov2, Katherine Wang2, Yan Yu3, Valerie Shafer2;1NSF REU Site Intersection of Linguistics, Language, and Culture, 2City University of New York Graduate Center, 3St. John's University
The purpose of this study is to examine speech processing in the auditory context of competing background speech “noise” to elucidate how early Spanish-English bilingual experience modulates speech processing. We measured the Mismatch Negativity (MMN) and Late Negativity (LN) components of event related potentials (ERPs). MMN reflects discrimination of auditory or speech contrasts (Näätänen, et al., 2007) and can be elicited at a fairly automatic level, but can be modulated by attention. The LN appears to reflect reorienting to the stimulus change. We hypothesized that bilinguals would monitor the auditory environment differently than American English monolinguals because of their different auditory experience and because studies indicate differences in performance between bilinguals and monolinguals on executive function tasks. Specifically, we predicted that bilinguals would show less “suppression” of a non-target speaker voice. ERPs to speech stimuli were recorded from 64 scalp sites in two conditions. In the Passive condition, participants’ attention was directed away (by watching a muted movie) from the speech, which consisted of a female voice uttering /ɑpə/ as standard and /æpə/ as deviant mixed with a male voice uttering /epə/ as standard and /ɑpə/ as deviant. In the Attend condition, participants were required to focus on the female voice /æpə/ by counting the deviants and to ignore the male voice. Preliminary results with six monolinguals and four bilinguals revealed that attention enhanced neural discrimination of the target /æpa/ for all participants, as expected. For the non-target deviant (male voice /ɑpə/) in the Attend condition, the MMN and LN were 60% smaller for monolingual listeners. In contrast, the bilingual listeners showed no reduction in amplitude. These findings suggest that bilingual experience leads to differences in monitoring speech information in the auditory environment. Further manipulations will be necessary to determine whether this pattern is related to differences in how monolingual and bilingual listeners inhibit interfering information in the Attend condition or rather to differences in how monolingual and bilingual participants attend to speech in the classic “passive” condition, where they are instructed to ignore the speech and watch a movie.
Themes: Perception: Auditory, Multilingualism
Method: Electrophysiology (MEG/EEG/ECOG)