Do Binaural Beats Work?
Binaural beats are an auditory illusion in the brain, created when two tones of different frequency are presented to different ears. Depending on the frequency of the binaural beat, different brainwave states are said to be induced, or ‘entrained’.
When it comes to binaural beats one of the first things that is already asked is: do binaural beats actually work? Well we’ve put together this comprehensive article in order to answer that question as fully as possible.
Binaural beats were discovered by Heinrich Whilhelm Dove, a Prussian physicist and meteorologist, in 1839. He found that simultaneously playing two slightly different frequencies to each ear produced a subjectively perceived pulsating beat in the brain. The frequency of the beat was the same as the difference between the two original frequencies.
Despite Dove’s observations, binaural beats remained nothing more than a curiosity until 1973, when a biophysicist called Gerald Oster published a research paper in the Scientific American. The paper, titled ‘Auditory Beats in the Brain’, documented how the brain interprets frequency signals and produces the perceived binaural beat effect.
Based upon his collated research, Oster argued the potential for binaural beats to be used as a tool in cognitive and neurological research. He also suggested that they could be used as a diagnostic tool for certain neurological conditions.
Since the publishing of Oster’s paper, research has continued to investigate binaural beats, and the understanding of how they work in the brain has developed considerably. However, despite Oster’s proposition of binaural beats being used as a diagnostic tool, much of the research has instead focused on their effect on consciousness and various neurological states.
As a result, there is now a growing number of companies developing binaural beat programmes for consumers and making various claims about their abilities. Some of the supposed abilities of binaural beats include their use in:
- Increasing intelligence
- Promoting better memory
- Enhancing meditation
- Aiding relaxation
- Reducing anxiety
- Relieving stress
Although a web search of binaural beats programmes will produce thousands of results insisting that binaural beats do work, scientific research has produced mixed results. There are also various other factors which need to be taken into consideration when determining whether or not binaural beats work.
The Neurophysiology of Binaural Beats
The human brain is an electrochemical organ and electrical activity emanating from it is displayed in the form of brainwaves. Brainwaves are measured like sound frequencies, in Hz – or cycles per second – and can be recorded using electroencephalography (EEG). Four main brainwave categories have been identified by neuroscientists:
Beta Waves:15-40 Hz – Beta waves are required in order to think and function consciously. They’re associated with being actively engaged in mental activities, concentrating on learning something, and being alert and focused. They’re also associated with over-thinking and worry. Beta waves are low amplitude, but the fastest of the four brainwaves. The frequency of them typically ranges from 15 to 40 cycles per second.
Alpha Waves: 9-14 Hz – Alpha brainwaves are slower in frequency, but higher in amplitude, and are associated with a feeling of relaxation. People typically experience this state when watching television, resting after completing a task, or meditating. The brain also produces alpha waves just before you go to sleep and again before you wake up.
Theta Waves: 5-8 Hz – Theta waves are of greater amplitude and slower frequency compared to beta and alpha waves. They’re associated with daydreaming, feelings of drowsiness, and active dreaming during REM (rapid eye movement) sleep. A person’s mental state during theta is generally very positive, where ideas flow and mental relaxation occurs.
Delta Waves: 1.5-4 Hz – The frequency of delta waves typically range from 1.5 to 4 cycles per second, but are of the greatest amplitude of all the brainwaves. Delta waves occur during deep sleep.
The four brainwave states are consistent across cultures and are common to humans of all ages. Whilst one brainwave state may predominate at any given time, research has shown that the other three are also detectable at the same time, even if only at the trace level.
Brainwaves and Binaural Beats
It has been alleged that you can use binaural beats to manipulate your brainwaves and induce your brain into one of the brainwave states detailed above. So how does it work?
A binaural frequency is created when a tone of one frequency is presented to the left ear and another tone of different frequency is presented to the right ear. The two tones must be listened to through headphones for the effect to happen.
If the two tones are played through stereo speakers then the binaural frequency can still be heard – as an audible pulsing sound – but the binaural beat auditory illusion won’t occur because the two tones are able to interfere with each other. The frequency difference between the two sounds must also be less than 30 Hz as anything greater than this would mean that the two tones would be captured separately by the two ears, resulting in no beat being perceived.
Therefore, the two sounds need to differ in frequency by less than 30 Hz and need to be completely separated, by traveling directly into your ear canals via headphones. This allows the brain to interpret the difference between the two frequencies, resulting in a binaural beat frequency.
The binaural beat frequency supposedly leads to a brainwave-synchronization process that some refer to as ‘entrainment’ or the ‘frequency following response’. The binaural beat is less of an audible sound and more of a subtle pulsing, allegedly causing your brain to synchronize itself with the beat frequency and feel the corresponding experience.
As an example, if a tone with a frequency of 114 Hz is presented to your right ear and a tone with a frequency of 124 Hz is presented to your left ear, your brain will interpret the difference between these two tones and produce a binaural beat frequency of 10 Hz. As you can see above, this frequency is within the alpha brainwave frequency range. Binaural beat theory proposes that the brain would ‘entrain’ itself to the 10 Hz frequency, thus producing the corresponding feelings associated with the alpha brainwave state.
Therefore, if a person was feeling anxious then the frequency of their brainwaves would typically be within the beta range. If they listened to a binaural beat track designed to induce an alpha binaural beat frequency, they should then become calmer and more relaxed and feel their anxiety lessening.
Are Binaural Beats Actually Effective?
Due to much of the focus on binaural beats centering around their holistic use, a lot of the information and ‘research’ about them is published by companies selling products based on binaural beat technologies. As a result, a lot of the positive claims are self-reported and not supported by scientific studies.
One of the largest and most-cited studies supporting the effectiveness of binaural beats technology was conducted by Huang and Charyton (2008). The meta-analysis of peer reviewed studies, titled A Comprehensive Review of the Psychological Effects of Brainwave Entrainment, found that binaural beats could be beneficial for memory, attention, stress, pain, headaches and migraines.
However, the author of the study was an employee for a company selling sound technology software, raising the potential for a conflict of interests. In addition to this, the majority of studies cited used a small subject sample, introducing problems with generalization.
Evidence in Favour of Binaural Beats
Some research studies, which did not have any affiliations with companies selling binaural beats technology, have found evidence which somewhat supports their effectiveness. These include:
- A recently published study in the British Journal of Oral and Maxillofacial Surgery found that binaural beats may be useful in reducing preoperative anxiety in dentistry. Sixty patients who were having impacted third molars removed were split into two groups. When their anxiety was recorded on a visual analogous scale, the experimental group that had listened to an alpha binaural beat for 10 minutes prior to the tooth being removed had a significant reduction in their anxiety compared to the control group that didn’t listen to the binaural beat. The researchers concluded that binaural beats may be useful in reducing preoperative anxiety.
- Another study which lends support to the claims that binaural beats can reduce anxiety was published in the Alternative Therapies in Health and Medicine Researchers found that listening to tapes imbedded with tones that created delta/theta binaural beats led to a significant reduction in self-reported anxiety in mildly anxious people.
- The benefits of using binaural beats during surgery were investigated by another study in Ninewells Hospital in Scotland. Researchers claimed that patients who listened to binaural beats required less of the anaesthetic fentanyl compared to those who listened to classical music or a blank tape. However, another similar study found no difference between those who listened to binaural beats and those who didn’t.
- One study of binaural beats found that whilst binaural beats did not have the ability to induce certain brainwave states, they did increase or decrease the activity of certain brainwaves already present. For example, one finding by the researchers was that alpha binaural beats led to increased theta activity and decreased beta activity. They concluded that binaural beats could affect functional brain activity, but that more research was required.
One of the limitations of some of the research detailed above is that of self-report. In the absence of a scientific measurement, self-report is often used. The problem with self-report is that if brain activity is not also measured then it cannot be known whether any brain changes, which may correspond with what a participant is feeling, are happening.
For example, in the tooth removal study detailed above we cannot know the effect that binaural beat frequency had on the brain, or whether it had any effect at all. All we know is that patients reported less anxiety after being exposed to the binaural beat frequency. It’s therefore difficult to draw conclusions about the efficacy of binaural beats.
Although the studies detailed above appear to support some of the claims that binaural beats work, when more scientific measures are used then it casts some doubt on their effectiveness.
Evidence Against Binaural Beats
One study published in the International Journal of Psychophysiology tracked brain activity changes in response to alpha and beta binaural beats. Using an EEG, researchers found no evidence that brain activity changed in response to the binaural beat frequencies.
However, participants only listened to the binaural beat frequency for one minute intervals. It is often recommended that binaural beats are listened to over a longer period of time (at least 10 minutes) for the binaural beat to have an effect. This may explain why the researchers didn’t observe any brain changes.
Another study which used an EEG measurement investigated the efficacy of theta binaural beats. The aim of the study was to replicate a previous one which had found significant increases in theta EEG activity following exposure to a theta binaural beat.
Theta binaural beats have some association with hypnosis and as such, both studies also investigated whether theta binaural beats could increase hypnotic susceptibility. Despite the prior findings, the current study found no increase in theta EEG activity or hypnotic susceptibility.
What might limit the effectiveness of binaural beats?
There are some potential explanations for the mixed findings regarding whether binaural beats work. Some studies have argued that binaural beats are ‘not suited for a one-size-fits-all approach’ and that individual factors need to be taken into consideration. Whilst one individual may respond very well to all types of binaural beats, somebody else might not respond at all.
Alternatively, one person might respond to alpha binaural beats, but not to any other kind. Binaural beats technology companies therefore suggest experimenting with different binaural beats. Some users of binaural beats only report effectiveness after several sessions, so repeated use is also encouraged if no effect is felt.
It cannot be denied that some people experience positive effects when listening to binaural beats, but there may be some alternative explanations as to why these purported effects occur.
Pink Noise: Many binaural beat sounds will have an overlay of pink noise. The sounds of rain or birdsong are examples of pink noise and have been proven to aid relaxation. Some studies have found no difference between groups which listened to binaural beats and those who listened to tracks of pink noise.
Music: Music has also been found to induce different feelings in people, such as relaxation or excitement.
There has been no proof that binaural beats are any different to music or pink noise in terms of their ability to induce certain brainwave states. In fact, it’s possible that it’s the overlaying music or pink noise creating the feelings reported, not the binaural beats themselves.
Indeed, one study found no EEG differences between one group that listened to the sound of rain and another that listened to the same noise with an underlying binaural beat frequency. Other measures used actually found that the binaural beats group experienced negative effects, such as increased depression and poorer immediate memory recall, after listening to the stimulus.
Placebo Effect: The placebo effect is commonly observed across a wide range of scientific research. In the case of binaural beats, if an individual is told that listening to a binaural beat frequency may produce a certain effect then that expectation may produce that effect regardless of whether or not the binaural beat frequency actually does anything to the brain.
In summary, it appears that although binaural beats may work for some people under certain conditions, the reasons for the effects seen are still unclear. The claims made about them are limited, often based on self-report, and they have frequently been found to be no more effective than other tools available to people.
In addition, brainwaves are incredibly complex and without further research it is impossible to know whether it is possible to induce certain brainwave states using binaural beat frequencies. Unfortunately, the limited amount of research into binaural beats means that we are unable to draw any solid conclusions about their effectiveness.