BINAURAL AUDITORY BEATS AFFECT VIGILANCE PERFORMANCE AND MOOD

When two tones of slightly different frequency are presented separatel y to the left and right ears the listener perceives a single tone that varies in amplitude at a frequency equal to the frequency difference between the two tones, a perceptual phenomenon known as the binaural a uditory beat. Anecdotal reports suggest that binaural auditory beats w ithin the electroencephalograph frequency range can entrain EEG activi ty and may affect states of consciousness, although few scientific stu dies have been published. This study compared the effects of binaural auditory beats in the EEG beta and EEG theta/delta frequency ranges on mood and on performance of a vigilance task to investigate their effe cts on subjective and objective measures of arousal. Participants (n = 29) performed a 30-min visual vigilance task on three different days while listening to pink noise containing simple tones or binaural beat s either in the beta range (16 and 24 Hz) or the theta/delta range (1. 5 and 4 Hz). However, participants were kept blind to the presence of binaural beats to control expectation effects. Presentation of beta-fr equency binaural beats yielded more correct target detections and fewe r false alarms than presentation of theta/delta frequency binaural bea ts. In addition, the beta-frequency beats were associated with less ne gative mood. Results suggest that the presentation of binaural auditor y brats can affect psychomotor performance and mood. This technology m ay have applications for the control of attention and arousal and the enhancement of human performance. (C) 1998 Elsevier Science Inc.