Temporal Coupling Between Speech and Manual Motor Actions

Speech production is part of the larger motor control system, and as such can be organized into coordinative structures with other motor behaviors that can then be parameterized as single functional units. Previous work has shown the magnitude of movements in coordinated speech and finger tapping covaries across repetitions. The current study expands on this previous work to examine the temporal coordination of these coordinated movements. Subjects repeated a spoken syllable while tapping their finger in time with their speech. On each trial, they placed an emphatic stress on a single repetition of either a spoken syllable or a finger tap, and were instructed to maintain their production in the other domain unchanged. Results show that explicit stress in either speech or finger tapping generally lengthens the stressed repetition in that domain as well as the synchronous repetition in the other domain. Additionally, stress of either a spoken syllable or finger tap causes some lengthening of the interval between repetitions in both domains. This cross-domain covariation of the interval between repetitions extends to unstressed repetitions as well. These results indicate that control of prosody may be defined over a wide set of articulatory components, not just the speech motor system.