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According to many websites and YouTube videos (including Wikipedia):

"Binaural Beats" are a proven brain wave entrainment audio stimulus that are guaranteed to alter your state of consciousness.

Understanding the claim in more detail:

We know that the brain operates at different frequencies, depending on your state of consciousness.

These are some examples:

Frequency range  Name               Usually associated with:
> 40 Hz          Gamma waves        Higher mental activity, including perception, problem solving, fear, and consciousness
13–39 Hz         Beta waves         Active, busy or anxious thinking and active concentration, arousal, cognition, and or paranoia
7–13 Hz          Alpha waves        Relaxation (while awake), pre-sleep and pre-wake drowsiness, REM sleep, Dreams
8–12 Hz          Mu waves           Mu rhythm, Sensorimotor rhythm
4–7 Hz           Theta waves        Deep meditation/relaxation, NREM sleep
< 4 Hz           Delta waves        Deep dreamless sleep, loss of body awareness

The theory behind "binaural beats" is that by watching/listening to stimulus at certain frequencies, you can invoke a state of mind in the listener relating to that frequency.

So if your brain is running at 25Hz (a frequency associated with anxious thinking and concentration), listening to a "binaural beat" of 6Hz would aid a listener change the frequency of their brain to 6Hz, and so invoke a state of consciousness associated with that frequency. In this case, changing the listener's mindset from anxiety to deep relaxation.

But is there actually any scientifically sound evidence to suggest that listening to "Alpha waves" could aid sleep? Or "Theta waves", meditation? Or "Beta waves" aiding concentration?

In other words: Is there any solid evidence that ANY frequency could help the listener achieve a state of awareness/consciousness that they were aiming for? Or is it all pseudo-science?

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    @Oddthinking You marked this question as a duplicate of a duplicate of a totally different question. My question isn't about erectile dysfunction, natural pain killers, or about legal "highs" :-/ – Django Reinhardt Dec 16 '13 at 0:03
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    I think the final answer addresses this too, but okay, I've re-opened it. Alternatively, we could just ask a master question "Do binaural beats have any side-effect on the brain?" and have the whole field covered in one go. – Oddthinking Dec 16 '13 at 1:32
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    A few years later it seems this topic is still not settled : supporting article vs conflicting article… (NB : not having access to articles, I rely on the abstracts.) – Skippy le Grand Gourou Mar 18 at 12:00
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There is research claiming positive effects of binaural beats, but many suffer from methodological weaknesses. I'll present two examples of weak studies, and one that in my opinion may show a real effect (but failing to rule out at least one confounding factor).

Owens et al. 1998

(Owens et al. 1998) tested on 29 subjects. Each subject performed a 30-minute visual vigilence task on three different days while listening to noise while listening to either simple tones (no binaural beats), or binaural beats in the beta (16 and 24 Hz) or theta/delta (1.5 and 4 Hz) range. Participants were blinded as to the presence of binaural beats.

Each participant participated in three 30-minute experimental sessions across three days.

Session 1 was intended as training and establishment of a baseline. The participant was presented the control stimulus (with no binaural beats) for this session.

Sessions 2 and 3 were treatment session, where the participants were presented with the beta and theta/delta binaural beats, one in each session, with the order counterbalanced across subjects.

They used a single-tailed t-test (rather than a two-tailed t-test) to test the hypothesis that the beta frequency beats would improve performance more than the theta/delta frequency beats would. They found a statistically significant increase in the number of correct targets and a statistically significant decrease in the number of false positives when using the beta frequency beats as compared to the theta/delta frequency beats. They also tested self-reported mood differences.

There are various methodological weaknesses to this research:

  • They did not confirm that the binaural beats were not noticed by the participants. They were audible to the experimenters when listening carefully, but only relied on the fact that no participant reported hearing the beats.

  • They used a single-tailed t-test with the justification that their hypothesis was that beta frequency beats would improve upon theta frequency beats. This is a nice story, but they provided no prior declaration of this hypothesis, or any rationale for why they would not have simply selected a null-hypothesis of no-difference. The single-tailed t-test is a more powerful test, and thus reports statistical significance for smaller differences. This really seems like an inappropriate use of a one-tailed t-test, as it removed the possibility of finding the opposite result.

  • They mention that session 1 was used for both training and establishment of a baseline, yet present no comparisons with a baseline. Were either of the treatment conditions better than baseline? This paper doesn't answer that question.

  • In my opinion, these are symptoms consistent with the researchers having tried various comparisons and analysis strategies (perhaps comparing against baseline, trying a two-tailed t-test, etc.) and only reporting those that turned out showing some effect.

Wahbeh et al. 2007

This was an uncontrolled pilot study. It was an unblinded, non-randomized trial. Participants were simply given a CD containing binaural beats and they listened to it over a 60 day period. This study admits that it is simply exploratory. It doesn't draw any conclusions concerning causation, because it was not designed to do so. It simply identified a few possible correlations (which may not even exist due to the methodological weakness described next) for future research to verify in a controlled experiment.

Methodological weakness:

  • They performed 35 separate hypothesis tests and found 4 statistically significant differences from the null hypothesis at the p=0.05 level. When using p=0.05, these tests are expected to produce 1 false positive for every 20 hypotheses tested. That means in 35 hypotheses tests, you should expect to find about 1.75 statistically significant results just by chance. They found 4, so maybe there's something there, but this is anomaly hunting, and the exact situation in which one should apply a correction factor to control for the family-wise error rate. They did not apply a correction factor.

Reedijk et al. 2013

This study is more rigorous. It asks the question, do binaural beats affect creativity. They used binaural beats that were noticeable by the participants, calling the binaural beats a form of "cognitive entertainment", and they added white noise in such a way that it "enhanced the clarity of the beats".

They compared a control (a non-beating tone), to alpha frequency, to gamma frequency and tested performance on a divergent thinking task (naming as many uses as possible for a common household item) and a convergent thinking task (given three seemingly unrelated words, find a single word that could be prepended to each to make three new words: market, hero, and star become supermarket, superhero, and superstar).

There were 24 subjects each exposed to each condition (control, alpha, and gamma), and had to perform each task (divergent and convergent) in each of the conditions. The order of condition and task was counterbalanced across subjects using a latin square design.

Eye blink rate was also recorded as a proxy for striatum dopamine levels.

In my opinion, they use appropriate statistical tests to conclude that the convergent thinking task is unaffected by the binaural beats and that the divergent thinking task is affected by the binaural beats (no matter the type), but mediated by the subject's baseline eye-blink rate (striatal dopamine levels). Binaural beats increased the performance of those with low striatal dopamine levels. Binaural beats did not increase, and perhaps slightly inhibited the performance of those with higher striatal dopamine levels.

In summary, this study found that audible binaural beats (no matter the type: alpha or gamma) resulted in improved performance at divergent thinking tasks for people with low levels of striatal dopamine.

The proposed mechanism is that binaural beats could be assisting in setting up synchronized neural states. That assistance may not be needed in people with more optimal levels of striatal dopamine.

They don't report a frequency-specific effect as stated in some of the quoted claims. They also note that the effect is individualized, as opposed to the broad claims in the question.

One weakness is that they didn't compare against other sounds with beats. Perhaps any audio with a consistent beat would be sufficient to produce this effect.

References

Owens, James D., E. Kasian Justine, and Gail R. Marsh. "Binaural auditory beats affect vigilance performance and mood." Physiology & behavior 63, no. 2 (1998): 249-252.

Reedijk, Susan A., Anne Bolders, and Bernhard Hommel. "The impact of binaural beats on creativity." Frontiers in human neuroscience 7 (2013): 786.

Wahbeh, Helane, Carlo Calabrese, and Heather Zwickey. "Binaural beat technology in humans: a pilot study to assess psychologic and physiologic effects." The Journal of Alternative and Complementary Medicine 13, no. 1 (2007): 25-32.

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    The third experiment shows an effect, but not the one claimed. Binaural beats are supposed to have a specific cognitive effect based on the beating frequency. – Sklivvz Jan 2 '14 at 4:25
  • I'm just presenting what the evidence says. The evidence is weak that there are frequency-specific effects. A more general and individualized effect has some evidence that I consider compelling. – user5582 Jan 2 '14 at 4:29
  • For example, gamma waves are supposed to make you more alert, so they are "recommended" for studying. – Sklivvz Jan 2 '14 at 4:29
  • Anyway, I'll chat with you in Skeptics Chat, if you want. – user5582 Jan 2 '14 at 4:30
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    To be clear: my objections above are the same as @DjangoReinhardt – Sklivvz Jan 4 '14 at 0:15
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There are a bunch of scientific papers who show that binaural beats do have effects.

Binaural Auditory Beats Affect Vigilance Performance and Mood published in Physiology & Behavior (Impact Factor 3.16) concludes:

Neural activity with slightly different volley frequencies from left and right ear converges and interacts in the central auditory brainstem pathways to generate beats of neural activity to modulate activities in the left temporal lobe, giving rise to the illusion of binaural beats. Cortical potentials recorded to binaural beats are distinct from onset responses.

In Binaural Beat Technology in Humans: A Pilot Study To Assess Psychologic and Physiologic Effects they gave eight participants a CD with delta (0–4 Hz) binaural beat frequencies to which they were supposed to listen daily for 60 days.

The results:

There was a decrease in trait anxiety (p = 0.004), an increase in quality of life (p = 0.03), and a decrease in insulin-like growth factor-1 (p = 0.01) and dopamine (p = 0.02) observed between pre- and postintervention measurements.

In frontiers of human neuroscience Reedijk et al wrote an article titled "The impact of binaural beats on creativity". In it they write:

Results showed that binaural beats, regardless of the presented frequency, can affect divergent but not convergent thinking. Individuals with low EBRs (Eye Blink Rate) mostly benefitted from alpha binaural beat stimulation, while individuals with high EBRs were unaffected or even impaired by both alpha and gamma binaural beats.

Given that I illustrated the presence of an effect I also want to say, that I don't agree with the word "guaranteed". There are probably plenty of ways to use the technique that doesn't have an effect.

Even if you have something that has an effect you should also be aware that it has an effect. Plenty of people might not understand what relaxation or concentration really means and therefore use corresponding brainwave entertainment time where they are more harmful than helpful.

I would especially be wary of being constantly exposed to such sounds as that could mess up the way the brain regulates itself. I do have heard of anecdotal reports of someone messing up his brain completely by going down that road.

I would also add that a lot of modern brainwave entertainment that's sold nowadays uses additional effects besides binaural beats. A popular software for adding such effects to audio files is Mind WorkStation. They have plenty of documentation if you want to learn about details.

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    Studies do show that they have effect, but they also show that they have completely different effects from the ones in the claim. Reading you answer one could have exactly the opposite impression. – Sklivvz Jan 1 '14 at 19:57
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    The (self-admitted) pilot study had no control. It seems very plausible that confounding factors (such as seasonal variations in insulin-like growth factor-1) accounted for the changes. – Oddthinking Jan 2 '14 at 0:26
  • @EbenezerSklivvze : I did address the notable (quoted) claim of the question. To the extend that the question also added a few additional nonnotable claims I didn't address all of them. They happen to be vague. Take the one of whether alpha waves help sleep. The first stage of sleep happens normally with theta brain waves. That means people who use the philosophy behind binaural beats are likely to use theta waves to induce sleep. The sleep issue also adds an additional problem of how well people sleep with headphones. – Christian Jan 2 '14 at 0:35

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