Internal versus external: oral-motor performance as a function of attentional focus.

Purpose: Previous studies (e.g., G. Wulf, M. Höss, & W. Prinz, 1998; G. Wulf, B. Lauterbach, & T. Toole, 1999; for a review, see G. Wulf & W. Prinz, 2001) have reported that limb motor performance is enhanced when individuals adopt an external focus (focusing on the effect of the movement) versus an internal focus of attention (focusing on body parts such as the muscles of the hand). This study tested the hypothesis that the effects of attentional focus on limb performance would also occur in the oral-facial system.
Method: Two groups of 23 participants were administered both hand and tongue impulse force control tasks in which each group was randomly assigned either an internal or an external focus of attention. Participants were required to exert rapid pressure bursts to achieve a target force level of 20% of their maximal strength.
Results: Consistent with limb studies, findings revealed a significant advantage of an external focus (greater accuracy, less variability) for both the hand and tongue control tasks, as opposed to an internal focus of attention.
Conclusions: Results are discussed relative to a constrained-action theory of motor control and future application to speech motor learning.