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
- 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.