Are the accessory facial movements of the stutterer learned behaviours?

The purpose of the present study was to explore the accessory nonverbal behaviours emitted by stutterers when their speech was fluent, normally disfluent, or stuttered. Subjects were 25 stutterers who were required to speak spontaneously for a 2-min. period. Seven types of nonverbal behavior were observed. Significant differences among the three speech categories were obtained for jaw movements, mouth movements, forehead movements, eyebrow movements, and head movements. Eyelid movements and eye blinks were nonsignificant. The results are discussed with respect to the various functions that can be attributed to nonverbal behaviour in stuttering.