Measuring reaction times: Vocalisation vs. articulation
Scobbie, James M.
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Schaeffler, S., Scobbie, J. M. & Schaeffler, F. (2014) Measuring reaction times: Vocalisation vs. articulation. In: Proceedings of the 10th International Seminar on Speech Production (ISSP), 5–8 May 2014, Cologne, Germany, pp. 379-382.
There is a sizeable delay between any formulation of an intention to speak and the audible vocalisation that results. Silent articulatory movements in preparation for audible speech comprise a proportion of this phase of speech production. The extensive literature on Reaction Time (RT) is based on the delay between a stimulus and the acoustic onset to speech that is elicited, ignoring the preceding silent elements of speech production in what is an utterance-initial position. We used a standard Snodgrass and Vanderwart picture-naming task to elicit speech in a standard Reaction Time protocol, but recorded the behaviour of two typical speakers with audio plus Ultrasound Tongue Imaging (201 frames per second) and de-interlaced NTSC video of the mouth and lips (60fps). On average, acoustic RT occurred between 120 to 180 ms later than a clearly observable articulatory movement, with no consistent advantage for lip or tongue-based measures.