When two coherent sounds with nearly similar frequencies are presented to each ear respectively with stereo headphones, the brain integrates the two signals and produces a sensation of a third sound called binaural beat.
I tried to google, but a lot looks like fake evidences and not having any scientific evidences. What is the evidence for binaural beat music producing different cognitive and/or neural effects as compared to non-binaural beat music?
Since I was asked in chat about binaural beats, and have been posed this question a number of times before besides, I looked into the most recent literature using Google Scholar for the single term "binaural beats" and restricted my search to papers published between 2010-2015. For convenience, this is the definition of a binaural beat I will use.
When two coherent sounds with nearly similar frequencies are presented to each ear respectively with stereo headphones, the brain integrates the two signals and produces a sensation of a third sound called binaural beat (BB). - Gao et al., 2014.
State of the evidence
Broadly speaking, some research on binaural beats does exist, but the evidence presented in the studies I examined is by and large negative, inconclusive or statistically underpowered with respect to the efficacy of binaural beats' ability to improve cognition, and to whether it is even processed differently from acoustic beats at all.
Much of the research that does exist seems to be published in journals whose credibility I cannot vouch for, and this answer should therefore be taken for what it is: a cursory review of the best literature I could find, not as scientific fact.
Are binaural beats processed differently?
"The perceptions of binaural beats involve cortical activity that is not different than acoustic beats in distribution and in the effects of beat- and base frequency, indicating similar cortical processing." - Pratt et al., 2010.
Do binaural beats entrain brain waves?
"We observed RP increase in theta and alpha bands and decrease in beta band during delta and alpha BB stimulations. RP decreased in beta band during theta BB, while RP decreased in theta band during beta BB. However, no clear brainwave entrainment effect was identified. Connectivity changes were detected following the variation of RP during BB stimulations. Our observation supports the hypothesis that BBs could affect functional brain connectivity, suggesting that the mechanism of BB-brain interaction is worth further study." - Gao et al., 2014.
Do binaural beats induce a frequency following effect?
"Analysis of changes in broad-band and narrow-band amplitudes, and frequency showed no effect of binaural beat frequency eliciting a frequency following effect in the EEG." - Vernon et al., 2011.
What evidence exists is mixed and, at best, inconclusive. Based on this, I will tentatively say that it appears the claims put forward by many commercial binaural beats companies, while theoretically plausible in some sense, are not empirically supported in the literature.
Therefore, the most prudent position for a consumer to adopt seems to be that binaural beat music is as preferable, but no more preferable than acoustic beat music. For researchers, of course, binaural beats remains theoretically interesting.
- Gao, X., Cao, H., Ming, D., Qi, H., Wang, X., Wang, X.,… & Zhou, P. (2014). Analysis of EEG activity in response to binaural beats with different frequencies. International Journal of Psychophysiology, 94(3), 399-406.
- Pratt, H., Starr, A., Michalewski, H. J., Dimitrijevic, A., Bleich, N., & Mittelman, N. (2010). A comparison of auditory evoked potentials to acoustic beats and to binaural beats. Hearing research, 262(1), 34-44.
- Vernon, D., Peryer, G., Louch, J., & Shaw, M. (2014). Tracking EEG changes in response to alpha and beta binaural beats. International Journal of Psychophysiology, 93(1), 134-139.
There is very little controlled, modern research on binaural beats. I could only find one source, referenced below, from the late nineties (although there are a few other, more recent non-experimental "pilot studies"). According to their study, "presentation of beta-frequency binaural beats yielded more correct target detections and fewer false alarms than presentation of theta/delta frequency binaural beats. In addition, the beta-frequency beats were associated with less negative mood."
It should be noted, however, that this study is comparing performance with beta BB to performance with theta/delta BB, not performance with BB to performance without BB. (Apparently there was a condition with "pure tones", but it isn't mentioned in any of the analysis.)
Binaural Auditory Beats Affect Vigilance Performance and Mood. James D Lane, Stefan J Kasian, Justine E Owens, , Gail R Marsh. Physiology & Behavior Volume 63, Issue 2, January 1998, Pages 249-252. DOI: 10.1016/S0031-9384(97)00436-8
From "Binaural Auditory Beats Affect Vigilance Performance and Mood":
Participants (n = 29) performed a 30-min visual vigilance task on three different days while listening to pink noise containing simple tones or binaural beats 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-frequency binaural beats yielded more correct target detections and fewer false alarms than presentation of theta/delta frequency binaural beats. In addition, the beta-frequency beats were associated with less negative mood. Results suggest that the presentation of binaural auditory beats can affect psychomotor performance and mood.
But I also found this: "Tracking EEG changes in response to alpha and beta binaural beats", saying
Analysis of changes in broad-band and narrow-band amplitudes, and frequency showed no effect of binaural beat frequency eliciting a frequency following effect in the EEG.
And finally Analysis of EEG activity in response to binaural beats with different frequencies
We observed Realtive Power (RP) increase in theta and alpha bands and decrease in beta band during delta and alpha Binraul Beats (BB) stimulations. RP decreased in beta band during theta BB, while RP decreased in theta band during beta BB. However, no clear brainwave entrainment effect was identified. Connectivity changes were detected following the variation of RP during BB stimulations. Our observation supports the hypothesis that BBs could affect functional brain connectivity, suggesting that the mechanism of BB-brain interaction is worth further study.
Another proof for effect of binaural beats is shown here
The Induced Rhythmic Oscillations of Neural Activity in the Human Brain
The effects of different induced extremely low frequency (ELF) electromagnetic field, audio (binaural-beat), visual (light flashes) and combination of audio and visual rhythms at the various electroencephalographic (EEG) rhythms were investigated. These experimental findings suggest that EEG activity under exposure to EMF 0.174mT (8.33Hz) sinusoidal low intensity EMF exhibited a substantial decrease in delta and theta bands and prove that there is a slight transition from beta to alpha band from beta-alpha ratio calculations of the Energy Spectral Density. During the visual and audio visual stimulation at alpha rhythms (i.e. 13-7.5Hz) a possible entrainment on overall EEG activity was elicited by substantial increase and decrease in spectral energy levels.
I'd like to add a reference about the scientific effects of binaural beats in the brain:
Auditory Beats in the Brain;
a transcript of the orginal paper by Gerald Oster, Scientific American, October 1973 (scanned original attached):
Slow modulations called binaural beats are perceived when tones of different frequency are presented separately to each ear.
The sensation may show how certain sounds are processed in the brain. If two tuning forks of slightly different pitch are struck simultaneously, the resulting sound waxes and wanes periodically. The modulations are referred to as beats; their frequency is equal to the difference between the frequencies of the two original tones.
Binaural beats have been widely regarded as a mere curiosity. A recent textbook on hearing does not mention them at all. Yet the measurement of binaural beats can explain the processes by which sounds are located -- a crucial aspect of perception. It is possible that hormonally induced physiological behavior changes may be made apparent by measuring the binaural-beat spectrum.
With the last sentence, Oster proposes an real application of binaural beats!
Additionally, the transcripter mentions the main points at the beginning of the pdf:
A few interesting things from the article to note:
- Oster's idea was to use the perception of binaural beats as a diagnostic tool because some people are unable to perceive and respond to them. Oster never mentions brainwaves or entrainment as a function of binaural beats. This is interesting since nearly every company advertising bina ural beats claims Oster invented binaural beat brainwave entrainment.
- People with certain neurological conditions, or at certain times of the month (women), vary in their ability to perceive and respond to binaural beats. There is also a ge nder difference in the abilit y to process the beats.
- Binaural beats only form if the two tones are separated by less than 26 Hz, 30 at most. This maximum declines as the carrier moves away from 440 Hz. Also, binaural beats wane completely past a carrier 1000 Hz.
- According to Oster, the depth of binaural beats is very small (3dB). In a test comparison, monaural beats produced a much larger neural response. This seems to follow in line with the research done by David Seiver (Comptronic devices), Transparent Corp and others in regards to monaural and isochronic tones producing stronger entrainment.