Binaural beats are a curious phenomenon. If
you listen to two tones through earphones, one to each ear, you can create a
detectable pulsing sound. The pulse, or beat, is at the same frequency as the
difference between the two tones. So for example a 400 hertz tone to the left
ear combined with a 410 hertz tone to the right ear, produces a psychological
beat sound at 10 hertz (i.e. pulsing 10 times each second). Therefore this beat
doesn’t exist in either tone, and it’s not being heard by either ear. In fact
it doesn’t exist in the real world, just in your perception. Furthermore, these
beats can be detected in brain signals, they have been recorded in the cat inferior
colliculus, amongst other brain areas, by single cell recordings, and in the human brain by
electroecephalography (EEG). In fact, binaural beats have the potential to
entrain brain waves, artificially altering the frequency of electrical brain
activity.
These binaural beats have been known about
for many years, however, recently the internet has made the audio tracks easily
available. With a computer and earphones, anybody can listen to them via
YouTube. And lots of people are, under the belief that you can improve
concentration, learning, relaxation etc. The tabloid media have taken the
opportunity to make a moral panic out of it, renaming it ‘i-dosing’, complete
with horror stories of people over-i-dosing. In fact there is little
evidence for the induction of psychological states with binaural beats, and the
greatest danger may simply be of hearing damage if they are listened too at
high volume.
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| The media´s typical ridiculous response to binaural beats |
Nevertheless, in theory, if brain waves can
be entrained, this would be a very useful tool in psychology and neuroscience. So
research on this topic is needed. Together with a biophysics student from Escuela
Superior Politécnica de Chimborazo in Riobamba, we have been testing out the
potential of theta frequency binaural beats on cognitive function and emotional
state. The experiment involves participants listening to electronic music for
15 minutes, and then performing a range of cognitive tasks designed to measure
creativity and initiation. In addition their emotional states are recorded. In
one condition there is a theta frequency binaural beat embedded in the
music, in the other condition a very similar pair of sinusoidal waves that do
not produce a binaural beat.
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| Data collection at Universidad San Francisco de Quito. Marco Lopez performs cognitive tests while the participant listens to the binaural beats. |
This research is ongoing. We’ll report what
we find in a future blog post.
