The Science of Binaural Beats

     In our modern world of technology, we are taught from a young age to think critically, plan for the future, and always strive for a higher goal. Though these lessons are certainly worthwhile, they promote a lifestyle of a very active and chaotic mind. With this being our modern default mode of thinking, the practice of meditation can seem very daunting. It can feel so foreign to be mindful of the present and to prevent the mind from time traveling. For this reason, helping novice meditators achieve a meditative state more easily would be of great benefit. Does such aid even exist? In this post, we will explore the science of binaural beats, and their potential benefit in aiding in the meditative process.

     What is a binaural beat? When two tones close to each other in frequency are played simultaneously we perceive a periodic fluctuation (or amplitude modulation) at a rate equal to the difference between the two frequencies. This effect is referred to as beating. For example, a tone at a frequency of 120Hz and a tone at a frequency of 123Hz frequency played simultaneously produce beating at a rate of 3Hz (with three fluctuations per second). In a normal listening environment, such as a room, beating can be experienced as a monaural phenomenon, with each ear deriving the sensation from the same information. Binaural beats use this effect by feeding the two tones to the left and right ear as separate signals. For this reason, binaural beating inherently relies on the use of headphones. At slower rates beating may be perceived as pleasant, whereas progressively faster rates are accompanied by the onset of roughness. For a certain rate of beating, the sensation of roughness depends on the frequency range of the tones used. Beating at rates in excess of 10-15Hz is generally reported as rough and unpleasant (Pulkki & Karjalainen 2015). Probably, for this reason, popular examples of binaural beats often employ masking noise, reducing the prominence of the effect. So, what makes these binaural beats so interesting? Well, some argue that EEG readings from the brain show wave synchrony between the brain waves and the binaural frequency, which is called the frequency following response (Lavallee et al., 2011). The brain seems to try and match its own frequency with the frequency of the third sound.

     This would be very helpful in encouraging states of meditation because meditation is characterized by achieving a different frequency of brain activation. There are various brain wave frequencies observed in the brain. Here we will discuss three: α (8-10.5Hz), β (13-18Hz), and Ө (4-8Hz). The lower the frequency, the calmer and more tranquil the mind. When we sleep, for example, we produce frequencies around Ө, which is very low in frequency. β frequencies are often characterized by complex analytical thinking, whereas α is characterized as a more calm and relaxed state of mind. It has been shown that meditators have increased frequency amplitude of α and sometimes can achieve Ө frequencies (Banquet, 1973). Evidently, a goal of meditation is to decrease brain wave frequency. So, in theory, using binaural beats that are low in frequency can help us meditate better because our brain will attempt to synchronize with the low-frequency binaural beat. There has been some research to show that novice meditators do seem to benefit from binaural beats in the Ө range (Lavallee et al., 2011). Other research has shown similar results, however using α waves that help in meditation (Gupta et al., 2016). This may go to explain how a meta-analysis review of binaural beats generated decreased anxiety and pain perception in individuals (Garcia-Argibay et al., 2019), as these are also side effects from meditation (Gard et al., 2012; Rubia, 2009). Similar to meditation, some research has even suggested that binaural beats are able to increase vagal tone, as observed through changes in heart rate (McConnell et al., 2014). Binaural beats seem to induce the same physiological changes as meditation does, suggesting it does help mediators achieve the correct state of mind.

     Though this research is interesting and the logic is sound enough, the evidence is far from conclusive. Many studies have attempted to observe the frequency following response while using binaural beats to no avail (Guruprasath & Gnanavel, 2015; Vernon et al., 2014). Additionally, a major study referenced in this post that did show a response, only noticed a response in novice meditators and not in experienced meditators (Lavallee et al., 2011). Perhaps the experienced meditators simply had greater focus, so the sound had no effect, as suggested by the researchers, or perhaps not. Lastly, even if the brain does synchronize its brain waves with external stimuli, there is a reason to believe binaural beats do not add to this effect.

     It should also be remembered that binaural hearing is intrinsically linked to spatial perception. In our day to day experience, the occurrence of an auditory event in only one ear only holds true towards high frequencies and/or low levels of sound. This most likely puts binaural beats in conflict with our expectation in terms of spatial rendering. In addition to the sensation of roughness, this may be another reason why some people report discomfort listening to binaural beats. Depending on the individual, this issue may offset the potential benefits of binaural beating for the purpose of meditation.

     One study compared beating under monaural with binaural beats and showed that monaural beats showed a greater frequency following response (Hink et al., 1980). This would indicate that the possible benefits of beating are not necessarily confined to the use of headphones or dependent on a hard left/right separation of tones and could thus be applied in a class setting, for example with the help of a PA system.

     In a domestic, urban environment, novice and experienced meditators alike may enjoy the added benefit of acoustic privacy as a result of masking noise. However, this infers the question as to a threshold of detectability. In other words, how much masking noise is too much or conversely, how much beating is loud enough – both at an absolute level as well as relative to each other. The case of monaural beating also raises the question of the required strength (modulation depth) of the effect. More clarity is also needed in terms of recommended duration of the application.

     Science is rarely ever straightforward. The pursuit of knowledge comes from different points of view constantly clashing into a refined theory of understanding. Perhaps binaural beats do help in meditation, perhaps beats or even just sounds help in general. Alternatively, perhaps it is best to continue our meditation practices in silence to maximize our concentration of the present. Lastly, it may help some people, but not others. For that reason, let us all continue to practice and find our own way through meditation.