Brain-behavior relationships in incidental learning of non-native phonetic categories

• Published in: Brain and language 2019-11, Vol.198, p.104692-104692, Article 104692
• Main Authors: Luthra, Sahil, Fuhrmeister, Pamela, Molfese, Peter J., Guediche, Sara, Blumstein, Sheila E., Myers, Emily B.
• Format: Article
• Language: English
• Subjects: Acoustic phonetics; Acoustics; Adult; Brain; Brain - diagnostic imaging; Brain - physiology; Educational activities; Female; Frontal Lobe - diagnostic imaging; Frontal Lobe - physiology; Functional magnetic resonance imaging; Humans; Implicit learning; Inferior frontal gyrus; Language; Magnetic Resonance Imaging - methods; Male; Non-native phonetic perception; Phonetics; Prefrontal Cortex - diagnostic imaging; Prefrontal Cortex - physiology; Second language learning; Sound; Speech perception; Speech Perception - physiology; Verbal Learning - physiology
• ISSN: 0093-934X; 1090-2155
• DOI: 10.1016/j.bandl.2019.104692

•Incidental paradigms show promise in promoting non-native speech sound learning.•Subjects completed fMRI sessions before and after incidental learning sessions.•Frontal brain regions differentiated non-native Hindi sounds even before training.•Individual success in learning predicted increases in frontal activation over time.•Findings support a role for frontal areas in non-native phonetic category learning. Research has implicated the left inferior frontal gyrus (LIFG) in mapping acoustic-phonetic input to sound category representations, both in native speech perception and non-native phonetic category learning. At issue is whether this sensitivity reflects access to phonetic category information per se or to explicit category labels, the latter often being required by experimental procedures. The current study employed an incidental learning paradigm designed to increase sensitivity to a difficult non-native phonetic contrast without inducing explicit awareness of the categorical nature of the stimuli. Functional MRI scans revealed frontal sensitivity to phonetic category structure both before and after learning. Additionally, individuals who succeeded most on the learning task showed the largest increases in frontal recruitment after learning. Overall, results suggest that processing novel phonetic category information entails a reliance on frontal brain regions, even in the absence of explicit category labels.