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Category: Project

Description: Recent evidence suggests that the motor system may have a facilitatory role in speech perception during noisy listening conditions. Studies clearly show an association between activity in auditory and motor speech systems, but also hint at a causal role for the motor system in noisy speech perception. However, in the most compelling "causal" studies performance was only measured at a single signal-to-noise ratio (SNR). If listening conditions must be noisy to invoke causal motor involvement, then effects will be contingent on the SNR at which they are tested. We used articulatory suppression to disrupt motor-speech areas while measuring phonemic discrimination across a range of SNRs. As controls, we also measured phonemic during passive listening, mandible gesturing, and foot-tapping. Full psychometric functions were fit to the data in each condition. Our findings indicate: (1) little to no effect of motor system suppression on performance; and (2) steep psychometric function slopes which may exaggerate the minimal effect motor suppression when performance is measured at a single SNR.