Trait/set interactions in EMG biofeedback.

Recently the efficacy of EMG biofeedback over other relaxation procedures has been questioned. Dispositional trait factors have been hypothesized as accounting for some of the contradictory results. The present study investigated the interactions of absorption and trait anxiety with instructional sets on levels of activity in the frontalis muscle. Subjects were given a set to relax by attending to biofeedback signals or a set to relax by letting go of all concerns and having a pleasant daydream. No biofeedback signals were provided the latter group. Both groups demonstrated reductions in activity of the frontalis muscle. No significant between-group differences and no significant interactions for absorption, trait anxiety, or experimental set were found. Both groups demonstrated pre-post decreases in state anxiety with subjects given the daydreaming set and no biofeedback showing significantly less post-treatment state anxiety than subjects who attended to biofeedback signals.