PHYS341/2023/Project17

Binaural Beats, Music, and Attention

Introduction

Binaural beats and music have proven to be practical tools for enhancing attention; however, there is a lack of discourse comparing which may be more efficacious. By analyzing past research and implementing a semi-controlled experiment, this project will explore the following:

1. What binaural beats are
2. How binaural beats vs. music impact attention
3. Which frequencies of binaural beats are associated with better attention
4. Whether music or binaural beats are more effective for attention

What are Binaural Beats?

Binaural beats are a newly emerging phenomenon in the field of acoustic science. Essentially, binaural beats are an auditory illusion that allows the listener to hear “beats” that do not exist. Two tones of different frequencies are presented separately to the left and right ears leading to the perception of a “beat” that differs in amplitude at a frequency equal to the frequency difference between these two beats.

If a listener is presented with a frequency of 290Hz in their right ear and 250Hz in their left ear, the listener would experience a 40Hz beat

Literature Review

How does Music impact Attention?

Listening to music is a complex phenomenon that affects multiple cognitive streams within the brain, such as auditory processing, working memory, temporal sequencing, pitch tracking, anticipation, reward, and emotion. Despite this phenomenon, however, music is associated with high attention levels as long as there are little to no perturbations to the auditory and executive systems. That is, completing the task (i.e., attention) is optimal when the music does not affect the systems required for the task and the systems required for listening to music.

Researchers have identified a few conditions to ensure that the cognitive systems remain unperturbed when one listens to music. However, one is discussed more in the context of attention: music familiarity. To illustrate music familiarity, Kirk and colleagues conducted a randomized control trial. They found that music familiarity (relative to music unfamiliarity) indicated faster reaction times (and attention) while listening to music. This finding is consistent with other research stating that familiar stimuli lead to minor perturbations to the auditory system, such that familiar music activated introspective thought (superior frontal gyrus), while unfamiliar music activated regions associated with working memory (superior parietal lobule).

How do Binaural Beats impact Attention?

Binaural beats are an emerging field within acoustic science, so there is little research on attention, but increasing evidence shows that binaural beats are associated with minor, significant improvements to attention. However, there is significant debate over which frequencies generate the best performance outcomes. A meta-analysis posited that alpha, beta, and gamma frequencies are each associated with increased attention; however, this was disproved by a randomized control trial that failed to generate sustained attention with beta frequencies. Conversely, studies have shown that 40-Hz (gamma) binaural beats are associated with attention and reaction time improvements. 40Hz may also be significant when considering that neurons oscillate within specific frequencies: Delta (0.1-4Hz), Theta (4-8Hz), Alpha (8-13Hz), Beta (13-30Hz) and Gamma (>30Hz). Therefore, improvements in attention with 40Hz binaural beats may induce certain brain states, such as cognitive and motor functions. The following graphs can illustrate the similarities between both types of gamma frequencies (top: Neural oscillations demonstrated by an EEG; bottom: Binaural beats demonstrated by a wave).

Gamma EEG Rhythms

Gamma Binaural Beats - 200Hz/240Hz (generated by Audacity)

Significantly, improvements in attention are mediated by a training effect, as demonstrated in an RCT conducted by Ross & Lopez (2020). Although participants in experimental and control groups remained the same during the baseline task, the experimental group consistently improved on the task over time, exceeding the control group. This may be difficult to replicate given the time for the project, but is nonetheless important to note.

Experiment 1

Since this is not a proper research study, both experiments include one participant (the researcher)

Method

There is mixed evidence over which frequencies should produce a 40Hz effect; while some experiments use 200Hz as their lower frequency, others use 300Hz or 420Hz. Further, there is no explanation for using these particular frequencies. The data is so mixed with these experiments that it is difficult to parse out which frequencies are associated with sustained attention. Therefore, the first experiment will compare different frequencies of binaural beats and attempt to see which, if any, are associated with greater sustained attention.

Binaural beats were found and used for both experiments 1 and 2 with the website https://onlinetonegenerator.com/binauralbeats.html. Both experiments will utilize the Sustained Attention to Response Task (SART); this task has been used in previous research that investigated cognitive effects with music and binaural beats. It is a cognitive task that has been proven to be associated with sustained attention that is easily accessible online. The SART requires the participant to respond by pressing the space bar as quickly as possible to all stimuli except one (i.e., “Go Trials”). Stimuli include numbers 0-9, with the exclusion stimuli as 3; a NoGo trial is when 3 appears. If the participant succeeds in not pressing the space bar when presented with 3, that is defined as a NoGo stimulus. Selective attention is considered higher when the percentage of NoGo trials are successful (“%NoGo success”). The data from this experiment included 225 trials with 25 NoGo trials.

Results

Performance differences on the SART on 200Hz, 300Hz, and 420Hz binaural frequencies were analyzed. This analysis assessed whether binaural beat frequencies across the three conditions affected selective attention. The average response for %NoGo success was computed for each condition (Table 1). Mean scores are highest for the 200Hz-240Hz condition (x=20).

Experiment 2

Method

There will be three conditions to investigate whether music or binaural beats are more effective for attention. The first condition is the baseline condition (control) with no music. The second condition will compare the binaural beat frequencies of 200-240Hz, as this was the most successful condition in the first experiment. The third utilize music (soft piano music) that is familiar to the listener. Similar to experiment 1, this experiment will use the SART task and compare which conditions are associated with greater sustained attention by analyzing the means of the %NoGo scores.

Results

Performance differences in the SART on each condition (binaural beats, music, and control) were analyzed. The same analysis as experiment 1 was implemented with each condition (Table 2). Mean scores are highest for the music condition (x=36).

Discussion

The first experiment is the first study known to the researcher that compares which frequencies are the most effective for sustained attention for binaural beats. In this experiment, binaural frequencies for the 200Hz conditions had higher scores on sustained attention, 300Hz was the median score, and the 420Hz condition had the lowest mean score on sustained attention. These scores are perhaps because 200Hz is the lowest of the given frequencies, closer to the gamma range. Since neurons oscillate at 40Hz per second, it may be best to induce a binaural beat of that frequency and play frequencies closer to that range (e.g., 40Hz-80Hz). Future studies may explore w

hether lower frequencies are associated with sustained attention rather than binaural beats.

In the second experiment, music had the higher score on sustained attention (x=36), followed by the control condition (x=25) and the 200Hz binaural beat (x=20Hz). This finding may implicate a few things. Firstly, familiar music is associated with greater sustained attention, corroborating other findings that posit similar outcomes. Secondly, the music played was Gymnopédie No. 1, written by Erik Satie. Like other music compositions, it ranges a few octaves. However, this piece is unique as it distinctly plays lower notes like G2 and E2. These notes are similarly associated with the frequencies of 98Hz and 82Hz. This correlation could further the assumption that lower frequencies, closer to gamma frequencies, are associated with greater attention. Further research is needed to prove this hypothesis.

A notable limitation of this study was only one participant for the sample. As such, it did not make sense to perform further statistical analyses like a t-test. However, if t-tests were to be performed, it would be more accurate to see if the results are statistically significant. Further, training effects could not be performed for the binaural beats experiments due to lack of time. It would be more accurate to see the results of similar experiments over a few weeks and with more participants.