Variations in self-paced behaviors in stutterers and nonstutterers.

Ten stuttering and 10 nonstuttering subjects performed self-paced rhythmic tasks with the finger and jaw and were asked to repeat "ah." The tasks were performed at three rates: "comfortable" rate; and "slightly higher" and "slightly lower" than comfortable, but still in the comfortable range. The stutterers performed each of the three tasks more slowly than the nonstutterers and were less variable than nonstutterers. The reduced rates and more constrained variability of the stutterers were interpreted as manifestations of less flexible systems, which may be more susceptible to breakdown.