Mimicry and the Perception of a Phonemic Contrast Induced by Silent Interval: Electromyographic and Acoustic Measures.

In the preceding paper of this session (J2) it was found that a phoneme boundary divides a continuum of silent intervals into two perceptual categories. The purpose of the present experiment was to see if the subjects' mimicry of the same acoustic continuum is graded, or whether it is, like the perception, categorical. Acoustic and electromyographic recordings were made of the productions of subjects during mimicry of each of the above stimuli. The acoustic records showed that time intervals introduced in mimicry were indeed categorical; however, the possibility remained that the speakers were, in some sense, making tentative or partial p gestures in the middle range of the continuum. Electromyographic recordings were used to test for the subjects' tendency to make such gestures. The electromyographic results were also entirely categorical: Either there was a normal burst of muscle potential at the lip (indicating a p gesture) or there was not. Thus, there was no evidence that subjects produce intermediate gestures, such as partial closure, in response to stimuli near the center of the continuum. [ABSTRACT FROM AUTHOR]