The role of awareness in the control of frontalis muscle activity.

An experiment was conducted to evaluate whether awareness of change in frontalis muscle activity was necessary and sufficient for voluntary control over the muscle. Forty subjects were required to relax, tense and complete both a test of awareness and an isometric magnitude production task, using the frontalis muscle. Following the completion of these pre-training assessment procedures, one group of subjects underwent either: Training in muscular awareness; biofeedback training in muscular control; both awareness and muscular control training; or a non-training control procedure. Following training, all subjects were again evaluated using the pre-training assessment procedures. The results indicated that an increase in awareness was not sufficient to produce an increase in muscular control, nor was it necessary for an increase in the ability to tense the frontalis muscle. These results suggest that Brener's model of voluntary control needs to be re-examined.