The speech tasks were as follows: single syllable /ba/ of 150 ms labeled “1S”

1. GENERAL BACKGROUND FINDINGS METHODS OBJECTIVE THE SELF-SELECT SPEECH PARADIGM AND KLAPP’S MODEL PREDICTIONS This work was funded by a Proposal Planning Grant awarded by the Office of the Vice President for Research at Texas A&M University Motor programming during speech articulation: An application of Klapp's two process model. J.H. Rhee, Texas A&M University, D.A. Robin, E. Maas, San Diego State University, D.L. Wright, Texas A&M University . • Klapp (1995) has described motor programming as involving two independent processes that precede the execution of a sequential action. The INT process involves retrieving information necessary to plan individual movement elements in the sequence and the SEQ process involves placing the movement elements into the correct order prior to execution • Klapp (2003) extended his two-process model of motor programming to speech articulation using separate CRT and SRT paradigms to target INT and SEQ processes respectively. • Immink & Wright (2001) utilized self-select paradigm to simultaneously evaluate the demands of INT and SEQ processes when performing sequences consisting of short and long key presses. • The speech tasks were as follows: • single syllable /ba/ of 150 ms labeled “1S” • single syllable /ba/ of 450 ms labeled “1L” • four syllable /ba/ of 150-450-450-150 ms labeled “4S” • four syllable /ba/ of 450-150-150-450 ms labeled “4L” • Six (6) blocks of practice were administered to each participant. • There were sixteen (16) trials per practice block which included four trials for each of the tasks identified above. • Each trial followed the self-select protocol depicted in Figure 1 (adopted from Immink & Wright, 2001). • During each trial ST, RT, and syllable timing accuracy were recorded (see Figure 1 caption for description of dependent variables) The primary objective of this work was to examine the role of specific motor programming processes identified by Klapp (1995) during speech articulation using the self-selection paradigm. Figure 1. Self-select paradigm separately assesses latencies associated for INT and SEQ processes in Klapp’s (1995) model. A trial begins with the “ready” signal being presented. Shortly after, the individual is provided a precue revealing the speech sequence that should be readied. Study time (ST) is defined as the interval between the presentation of a precue informing the participant of the nature of the upcoming responses and the participant indicating they are ready by “left-clicking” a mouse. This interval is assumed to capture the temporal demands of the INT motor programming process. Following the execution of the mouse click a variable fore-period occurs prior to the presentation of the “GO” signal. RT is defined as the interval between the presentation of the “GO” signal and initial articulation of the first /ba/. Initial articulation was defined as in Zeigler & Deger (2001) as the 15% min-to-max threshold of the rising SPL-contour. The RT interval is assumed to capture the temporal demands of the motor programming process labeled SEQ. • Key findings • Mean RT did not show a significant change as a function of syllable duration, but ST increased as the duration of the syllable increased. • Both MeanRT and ST showed a significant increase as the number of syllables that needed to be placed in serial order increased. • Interpretation • The present findings indicate a broader applicability of Klapp’s two process model of motor programming beyond discrete sequence production tasks. • Syllable duration is a form of speech complexity that impacts preparatory processes that can be pre-programmed. This would occur via the process INT in Klapp’s model. • Serial order of speech articulation is resolved following the imperative signal and is resolved via the process SEQ (cf. Klapp, 2003 and alternative role for SEQ in speech articulation). • Based on previous work with discrete sequence production tasks the following is expected in this speech context: • Complexity of the single syllable response, in this case determined by greater duration, will require more INT processing which should be manifest as a greater ST for 1L vs. 1S articulations. • Articulations that involve more syllables should require more SEQ processing which will be manifest as a greater RT for the 4 vs. 1 syllable articulations. • Because the 4-syllable articulations in the present study involve planning /ba/ for two different durations, we also anticipate a larger ST for the 4 syllable vs. 1 syllable articulations due to a greater INT demand in the former case.