ABSTRACTThis study evaluated the effectiveness of laryngeal muscle biofeedback, a common treatment for subvocalization, utilizing a strict control group structure. Subjects were 29 undergraduates assigned to Laryngeal Feedback (N = 10), Masseter Feedback (N = 10), or No Feedback Control (N = 9) conditions. The results indicated that laryngeal muscle biofeedback had no specific treatment effect; however, masseter biofeedback demonstrated a specific treatment effect when the new procedure was utilized. Subjects in the Masseter Feedback Group displayed masseter EMG levels which were substantially lower than subjects in the Laryngeal Feedback Group (p<.05). In order to validate the results of the biofeedback control procedure, accuracy of myogenic perception was also tested, and found to be significant for the masseter (p<.001) but not for the laryngeal muscle. It is shown that the biofeedback control procedure can more accurately assess the presence or absence of specific treatment effects in biofeedback. Theoretical implications of the myogenic perception concept are discussed, and suggestions for future research in biofeedback and myogenic perception are provided.