A High-Density EEG Investigation into Steady State
Binaural Beat Stimulation
Peter Goodin, Joseph Ciorciari*, Kate Baker, Anne-Marie Carrey, Michelle Harper, Jordy Kaufman
Brain and Psychological Sciences Research Centre, Swinburne University of Technology, Hawthorn, Victoria, Australia
Binaural beats are an auditory phenomenon that has been suggested to alter physiological and cognitive processes
including vigilance and brainwave entrainment. Some personality traits measured by the NEO Five Factor Model have been
found to alter entrainment using pulsing light stimuli, but as yet no studies have examined if this occurs using steady state
presentation of binaural beats for a relatively short presentation of two minutes. This study aimed to examine if binaural
beat stimulation altered vigilance or cortical frequencies and if personality traits were involved. Thirty-one participants were
played binaural beat stimuli designed to elicit a response at either the Theta (7 Hz) or Beta (16 Hz) frequency bands while
undertaking a zero-back vigilance task. EEG was recorded from a high-density electrode cap. No significant differences were
found in vigilance or cortical frequency power during binaural beat stimulation compared to a white noise control period.
Furthermore, no significant relationships were detected between the above and the Big Five personality traits. This suggests
a short presentation of steady state binaural beats are not sufficient to alter vigilance or entrain cortical frequencies at the
two bands examined and that certain personality traits were not more susceptible than others.
Citation: Goodin P, Ciorciari J, Baker K, Carrey A-M, Harper M, et al. (2012) A High-Density EEG Investigation into Steady State Binaural Beat Stimulation. PLoS
ONE 7(4): e34789. doi:10.1371/journal.pone.0034789
Editor: Susanne Hempel, RAND Corporation, United States of America
Received June 30, 2011; Accepted March 8, 2012; Published April 9, 2012
Copyright: ? 2012 Goodin et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Funding: This project was funded by the Faculty of Life and Social Sciences. The funders had no role in study design, data collection and analysis, decision to
publish, or preparation of the manuscript.
Competing Interests: The authors have declared that no competing interests exist.
* E-mail: firstname.lastname@example.org
Externally produced modulation of cortical frequencies can be
witnessed via electrophysiological recordings using simple stimuli
such as light oscillating at a stable frequency  or acoustics such
as human speech or consistent tones [2,3]. Known as the
Frequency Follow Response (FFR) , it has been suggested that
numerous physiological and psychological processes can be altered
through external means, effectively entraining the brain to
synchronize neural activity with the stimuli (see  for a recent
review of existing literature). Currently there are few studies that
examine the role individual differences may play in affecting
The Five Factor Model (FFM) of personality  identifies five
traits of personality; Neuroticism (N), Extraversion (E), Openness
to Experience (O), Agreeableness (A) and Contentiousness (C) and
has been subject to a large amount of study examining possible
electrophysiological relationships [11,12,13]. In a study by Stough
et al.  photic driving was used to examine correlates of
personality traits and entrainment. They found the personality
traits O and C were associated with increased Theta and Beta
activity across the cortex, while A showed a positive correlation in
left central and temporal areas. Unfortunately no baseline period
was used, so the results could be due to naturally higher levels of
oscillatory activity in some personality traits, regardless of any task
It is currently unknown whether cortical activity is alterable
through the FFM using auditory stimuli to generate entrainment.
One such method purported to generate cortical entrainment are
binaural beats. Binaural beats occur when two sinusoidal waves at
slightly differing frequencies are presented separately to each ear
, which are then generally experienced as a pulsating auditory
sensation at the difference of frequency between the two waves.
For example, a standard tone 400 Hz played to the left ear and a
carrier tone of 407 Hz played to the right ear would produce the
sensation of a 7 Hz binaural beat. Binaural beats are best
perceived when the carrier and standard tone frequencies are at
approximately 400 Hz with differences between the two frequen-
cies of no more than 35 Hz .
Studies have shown a neurological basis of binaural beats
perception which have assisted in identifying subcortical regions
associated with processing phase differences between sounds.
These have been found to be generated by neurons in the inferior
colliculus, auditory cortex [15,16] and the medial olivary nucleus,
all of which are thought to be involved in processing and
integration of auditory stimuli . The effect of binaural beats on
psychological and biological aspects however has been somewhat
A study examining binaural beat alterations on neuropsycho-
logical factors  found Theta (7 Hz) stimulation binaural beats
to have a disadvantageous effect on memory in for the form of
immediate recall of words, while an examination into the use of
binaural beats as a potential treatment for anxiety failed to
produce statistically significant results . The use of downward
frequency cycling binaural beats from Alpha to Delta as a
treatment for insomnia  did find there was a significant
increase in patient relaxation but suggested this may have been
due to the calming music that typically accompanies commercially
purchases binaural beat stimulation packages. A study into
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vigilance modulation using binaural beats by Lane et al. 
found that Beta frequency binaural beats improved attention,
resulting in participants correctly identifying more targets and
fewer false alarms over a 30-minute period than those stimulated
by Delta/Theta frequencies. Studies examining electromagnetic
changes generated by binaural beat entrainment have yielded
inconsistent results. Some [7,16,22,23] have reported increases in
spectral density at Theta frequency using both event related and
steady state presentation methods, while others [8,18] have failed
to find evidence of the FFR using steady state presentation.
Based on the above, this study had three main aims:
1. To examine the effect of binaural beat stimulation on vigilance
in a zero-back task,
2. To determine if cortical frequency entrainment is possible
using steady state binaural beats, and
3. To partially replicate and extend Stough et al.  to
determine if personality type affects baseline cortical frequen-
cies and binaural beat entrainment.
As Stough et al. found that Beta and Theta frequencies were
correlated with personality traits and alterations in vigilance; the
current investigation employed these same frequencies for analysis.
We hypothesised that, when undergoing stimulation by the Beta
frequency carrier tones, participants would show increased
vigilance as evidenced by faster reaction times to stimuli and
there would be increased Beta and Theta cortical frequency power
during binaural beat stimulation. It was also hypothesised that the
magnitude of scores in O and C would be positively correlated
with perceptual speed and overall cortical power of Theta and
Beta frequencies. Finally, we hypothesised that those who scored
higher in A would show higher Beta frequency power in the left
temporal and central cortical areas. No specific hypotheses were
made relating to baseline periods, Neuroticism or Extraversion
Forty-five participants were initially recruited from the general
public and from a Melbourne university community. Exclusion
criteria for the study consisted of any reported neurological
disorder or known hearing damage or loss. Data from 14
participants was removed from the study due to file corruption,
missing electrophysiological or behavioural data, (4 females, 3
males), excessive artifact on the EEG (2 females, 3 males) and
reports of not being able to perceive the binaural beats (1 female, 1
male). This left a total cohort of 31 participants in the study (20
females, 11 males) with ages ranging from 18 to 60 (M=28.90,
S.D.=10.82). Four were left-handed (3 female, 1 male). Written
informed consent was obtained from all participants involved in
the study; which was approved by Swinburne University’s Human
Research Ethics Committee.
Participants’ personality trait scores were measured using the
NEO Five Factor Inventory (NEO FFI) questionnaire . The
NEO FFI consists of 60 items measuring personality traits across 5
domains (Neuroticism, Extraversion, Openness to Experience,
Agreeableness and Conscientiousness) on a 5-point Likert scale
(1=Strongly Disagree, 5=Strongly Agree) with a theoretical
range for each personality trait between 15 and 60. Internal
consistency and test-retest reliability have been found adequate.
Binaural beats at 7 Hz (Theta) and 16 Hz (Beta) were produced
using BrainWave Generator software version 3.1.12 (http://www.
bwgen.com/). A 400 Hz standard tone and a 407 Hz for Theta or
416 Hz for Beta carrier tone were used to attempt entrainment.
All stimuli were played to participants at 70 dB SPL, which is
within the range recommended by Stevens et al.  to induce
All binaural beat tones were two minutes in length, with a total
of 4 minutes continued presentation while white noise baseline
was presented between binaural beat stimulation epochs. Two
minutes of constant stimulation per ear was deemed an acceptable
timeframe to detect entrainment as studies applying binaural beats
for less than two seconds have detected event related potential
modulation [16,23], while the results of a recent steady state study
 suggest entrainment happens within seconds of the binaural
stimulation being presented. The waveforms were inspected for
imperfections that could distort the tones using the freeware audio
editing programAudacity version
The experimental procedure was presented using E-Prime
version 18.104.22.168 on a Dell Optiplex 755 computer. A common
paradigm used in neuroimaging [25,26,27,28,29], the 0-back task
was used as a measure of vigilance and to keep participants in an
approximately similar state of arousal. The tones used to elicit a
binaural beat were played through a pair of stereo headphones
positioned so the earpieces and headband did not press against
electrodes and were stable while participants engaged in the
vigilance task. A computer keyboard was used to register
participant’s response times (in milliseconds) to the 0-back task
target stimuli as well as incorrect answers and the onset of the
EEG recording and Electrode Placement
EEG data was collected using an Electrical Geodesics Inc. (EGI)
EEG acquisition system consisting of a 128-channel Hydrocel
Geodesic Sensor Net and a Net Amps 300 high-impedance
amplifier. The data were recorded using EGI’s acquisition
software (i.e., Net Station version 4.2.4) on an Apple Mac Pro
computer running OS 10.4. Impedances were kept at less than
50 kV as per the manufacturer’s instructions (Electrical Geodesics,
Inc, Eugene, OR) and examined for electrode bridging. The EEG
signal was sampled at 500 Hz. Figure 1 illustrates the location of
electrodes for high density EEG recording and the allocations to
specific anatomical regions for data reduction.
Pre-experiment and Training
Participants were seated in a quiet recording room and asked to
complete a demographic questionnaire which included items on
gender, age and handedness. The participant’s head was measured
for the appropriate electrode net size and an audiometric test was
performed. During the test, participants were played a tone over a
10-second period that alternated from the left to right channel at
the 5-second mark. The tone consisted of a 400 Hz sinusoidal
waveform and was played at 70 dB SPL.
Following the audiometric test, participants listened to a 30-
second example of binaural beat recording at alpha frequency
(13 Hz) to minimize any potential interactions on the frequencies
of interest. Participants then completed the NEO FFI question-
naire. After completion of the questionnaire the electrode net was
place on the participant’s head and secured as suggested by the
manufacturer’s instructions (Electrical Geodesics, Inc, Eugene,
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The experiment consisted of eight epochs, with four binaural
beat presentations; two of Beta (16 Hz) and Theta (7 Hz)
frequencies to left and right ears respectively (See Figure 2). The
epochs consisted of a two-minute white noise control period, two
minutes of a binaural beat carrier tone played to the left ear, a 30-
second white noise rest period, two minutes of a binaural beat
carrier tone played to the right ear, a second two minute white
noise control period then a repeat of the earlier epochs, but
playing the alternative frequency. The total running time was
13 minutes per participant. EEG was recorded concurrently
during all epochs. The order in which binaural beat frequency
stimulation occurred was counterbalanced, with approximately
half the participants receiving Beta frequency stimuli first.
In order to maintain engagement, test vigilance and control for
eye movement artifact, participants were asked to do two
consecutive tasks during the recording session. The first was a
continuous 0-back task similar to that described in . Capital
letters appeared centrally on a screen every five seconds and
participants were asked to press a key when the target letter, a
capitalized M appeared. N was not used in the task due to its
similar appearance to the target letter. In total, 29 target
presentations over the 13-minute experiment occurred. During
the binaural beat stimulation periods, 10 targets occurred during
Beta stimulation (6 during left binaural beat carrier tone) and 11
during Theta stimulation (6 during left binaural beat carrier tone
The second task required participants to indicate when they
perceived the binaural beat by pressing another key. Their
reaction time relative to the start of the stimulation epochs were
recorded and used for analysis. Participants were given the length
of the stimulation epochs (two minutes) to answer and instructed to
only press the key when they were aware of the beat. If they were
unable to detect the beat, they were instructed not to push the key.
In addition to the key presses related to binaural beat perception,
upon completion of the experiment participants were explicitly
asked if they perceived the beats at any point during the study.
Participants indicating they did not hear the beats (n=2) were
excluded from further analysis.
The recorded EEG was analysed using Brain Vision Analyzer
Data was converted from Net Station format to Brain Vision
Analyzer format via an EEGLAB plug-in. The data were filtered
using a low cut of .05 Hz (12 dB per octave) and a high cut of
35 Hz (48 dB per octave) with an averaged electrode reference. All
participant data was segmented into blocks relative to the
condition presentation time and corrected for EOG using the
Gratton, Coles and Donchin  method. A Fast Fourier
transformation was applied and the absolute spectral power for
the two frequency ranges for each electrode were calculated
(5.5 Hz to 7.5 Hz for Theta band and 15.5 to 17.5 for Beta band).
Data reduction was employed for exploratory purposes; the
electrodes were grouped into the major left and right cortical lobes
(frontal, central, parietal, temporal and occipital), with each area
containing between eight and ten electrodes. Electrodes at the
Figure 1. Included Electrodes by Cortical Area. Note: FL=Front Left, FR=Front Right, CL=Central Left, CR=Central Right, TL=Temporal Left,
TR=Temporal Right, PL=Parietal Left, PR=Parietal Right, OL=Occipital Left, OR=Occipital Right.
Binaural Beat Stimulation, EEG and Personality
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extremes of the net were culled from the analysis due to their
potential for high levels of EOG and EMG artifact. The average
spectral powers for the two bands were calculated for each group.
The NEO FFI questionnaire scores were compiled and
calculated using a Teleform scanner. NEO FFI scores were
divided into low, average and high to examine possible effects of
personality trait strength. Categories were created by calculating
the means and standard deviations for each personality trait and
split according to one standard deviation. A score of low for each
of the personality traits were one standard deviation below the
mean or less, while a score of high was one standard deviation
above the mean or more. Additionally, as the FFM is thought of as
a continual construct, NEO FFI scores were also kept as non-
categorical, interval data for correlational analysis.
Reaction Time Data
Individual binaural beat stimulation reaction time data was
calculated by taking the mean of all target letters that appeared
during the binaural beat conditions (for example, left Beta carrier
tone, right Beta carrier tone) while mean Beta and Theta reaction
time data was calculated from left and right reaction times in the
particular frequency range. Baseline reaction times were calculat-
ed from target stimuli presented during the two white noise
In order to increase statistical power, the counterbalanced
groups were collapsed into a single collection. Chi square tests
revealed no significant difference between the groups for sex (x2(1,
N=31)=2.203, p=.258) or handedness (x2(1, N=31)=1.651,
p=.304). One-way analysis of variance (ANOVA) examination
determined no significant differences between the counterbalanced
groups for age (F(1,29)=.05, p=.811 NEO trait scores (N
(F(1,29)=.70, p=409)), binaural beat perception reaction time
(F(1,29)=.22, p=.636)), control spectral power (Beta frequency
(F(1,29)=.01, p=.949), Theta frequency (F(1,29)=.69, p=.410)),
experimental spectral power (Beta frequency (F(1,29)=.04,
p=.837), Theta frequency (F(1,29)=3.94, p=.057) or the reaction
times from the vigilance task conditions (binaural beat off
(F(1,29)=2.86, p=.101), averaged over frequencies binaural beat
on (F(1,29)=1.32, p=.259), Beta frequency on (F(1,29)=3.16,
p=.086), Theta frequency on (F(1,29)=.13, p=.718). NEO group
membership numbers are shown below in Table 1. There was an
approximately normal distribution across all five personality
To examine if binaural beats affected vigilance, paired samples
t-tests were conducted. The tests did not reveal any significant
difference between left Beta carrier tone stimulation and right Beta
carrier tone stimulation reaction times (t(30)=.540, p=.593), Beta
and Control reaction times (t(30)=.84, p=.403), Beta and Theta
stimulation reaction times (t(30)=1.12, p=.272), left Theta carrier
tone stimulation and right Theta carrier tone stimulation reaction
times (t(30)=.995, p=.347) or Theta stimulation and Control
times (t(30)=1.03, p=.310). This suggests vigilance as measured
by reaction times to a 0-back task was not altered with beat
binaural beat stimulation of either Beta or Theta frequencies,
contrary to the hypothesis. The means and standard deviations of
the conditions are shown below in Table 2.
Figure 2. Experimental Protocol and Timings.
Table 1. Neo Group Membership including total numbers
NEO Group Range TotalPercentage %
Neuro Low9 29
Extra Low4 12.9
Open Low5 16.1
Note: Neuro=Neuroticism, Extra=Extraversion, Open=Openness to
Experience, Consc=Conscientiousness, Agree=Agreeableness.
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Correlational analysis was employed to determine if there were
interrelationships not detected by the t-tests due to the formation
of three categorical groups. NEO personality traits and reaction
times in the vigilance task were examined on a continuous
dimension, however no significant results between the two were
found (Table 3). There were significant positive correlations found
between C and N (r=.45, p=,.01), C and E (r=.45, p=,.05),
Theta and Beta binaural beat stimulation reaction times (r=.39,
p=,.01) and Control reaction times during Theta (r=.49,
p=,.01) and Beta (r=.91, p=,.01) conditions. These results
suggest that personality traits as measured by the NEO do not alter
susceptibility to binaural beat induced increases in vigilance.
To determine if cortical frequencies could be entrained through
binaural beat stimulation, a repeated measures ANOVA was
employed. No statistical differences were detected between Beta
control and stimulation conditions (F(1,30)=1.23, p=.227) or
Theta control and stimulation conditions (F(1,30)=.24, p=.625).
This was contrary to the hypothesis that binaural beat stimulation
would affect a level of entrainment in the cortex at Beta and Theta
frequencies. The means and standard deviations of cortical power
can be seen in Table 4 below.
To examine the viability of the hypothesis that those who scored
high on the O and C personality traits would have increased Beta
and Theta cortical power spectral density respectively during
binaural beat stimulation, 3(Neo trait score)62(Condition) ANO-
VAs were conducted for each of the personality traits and binaural
beat frequencies used in the study . The table below (Table 5)
shows the means and standard deviations of Beta cortical power
spectral density by NEO personality traits, trait scores and
The ANOVA found no significant interactions between white
noise control and Beta stimulation condition for any of the NEO
personality traits (N (F(2,28)=.50, p=.611, E F(2,28)=.51,
p=.603, O F(2,28)=.11, p=.896, C F(2,28)=.01, p=.992, A
F(2,28)=.20, p=.816). These results did not support the third
hypothesis, as Beta power did not increase in O with Beta binaural
beat stimulation compared to control. Table 6 (below) contains the
means and standard deviations by condition and score for Theta
binaural beat stimulation.
The statistical analysis conducted found no significant interac-
tions between the NEO traits, score or Theta stimulation
condition for N (F(2,28)=1.39, p=.265), E (F(2,28)=.20,
p=.947). There was a significant interaction between C and
Theta binaural beat stimulation on Theta frequency power
(F(2,28)=3.67, p=.038), however this result failed to survive a
post-hoc Student-Newman-Keuls test (p=.243). These results also
did not support the hypothesis as cortical Theta power levels in C
did not differ from the control period.
Examination of the fourth hypothesis was conducted using a
correlational analysis as performed in the study by Stough et al.
Correlations for personality traits and cortical spectral density
power in both Beta and Theta stimulation conditions in the
temporal-central region are shown in Table 7.
As can be seen from the table, no significant correlations were
detected between the NEO traits, cortical area or spectral density
powers at Control, Beta or Theta frequencies. This did not
support the hypothesis that increases in A score would show
increases in Beta power in the left temporal-central cortical areas.
It also suggests that personality traits as measured by the FFM do
not increase or decrease the power of cortical frequencies in either
the Beta or Theta range.
Table 2. Means and Standard Deviations of Reaction Time
(ms) in the Vigilance Task during Beta binaural beat
stimulation, Theta stimulation and Control conditions.
ConditionReaction Time Mean (S.D.)
Beta Left Carrier 645.17 (317.39)
Beta Right Carrier615.22 (133.61)
Theta Left Carrier582.35 (125.23)
Theta Right Carrier619.32 (254.54)
Beta 643.52 (279.67)
Beta Control 629.47 (297.13)
Theta 596.42 (154.98)
Theta Control 631.95 (162.15)
Table 3. Correlation Table of NEO Personality Traits and Vigilance Task Reaction Time during Beta, Theta and Control Conditions.
Neuro ExtraOpen ConscAgreeBetaRT BContRT ThetaRT TContRT
Consc .46** .41* 0.251.00
20.24 0.31 0.040.15 1.00
**. Correlation is significant at the 0.01 level (2-tailed).
*. Correlation is significant at the 0.05 level (2-tailed).
Note: Neuro=Neuroticism, Extra=Extraversion, Open=Openness to Experience, Consc=Conscientiousness, Agree=Agreeableness, BetaRT=Beta Reaction Time,
BContRT=Beta Control Reaction Time, ThetaRT=Theta Reaction Time, TContRT – Theta Control Reaction Time.
Binaural Beat Stimulation, EEG and Personality
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This study aimed to determine if binaural beats presented at
frequencies corresponding to Beta (16 Hz) and Theta (7 Hz) could
alter the cognitive faculty of attention through a vigilance task, if
they could be used to entrain the brain to their particular
resonance, and if personality traits as measured by the NEO FFI
mediated either of the previous variables. Four hypotheses were
formulated based on previous findings in order to test the aims;
that Beta frequency stimulation would assist in sustaining
vigilance, binaural beat stimulation at either Beta or Theta
frequencies would increase overall cortical power at those
frequencies, that the personality traits of O and C would show
increased susceptibility to Beta and Theta beat entrainment
respectively and that A would show increased power in Beta
frequency in the left temporal-central areas. Statistical analysis
revealed that none of the four hypotheses were supported. There
were no significant changes in reaction times in either Beta or
Theta stimulation or across the NEO traits, which is contrary to
the results reported by Lane et al. This may be due to the
frequencies in which binaural beats were presented to participants
or differences in measurement of vigilance between the two
studies. The current study played four minutes (two minutes per
ear) of each frequency binaural beat to participants, and used
16 Hz and 7 Hz as the intended entrainment frequencies. By
contrast, Lane et al. used a 30-minute task in which participants
were presented with binaural beats at 1.5, 4, 16 and 24 Hz, with
carrier frequencies cycling from 100 to 300 Hz and combined
lower and higher frequencies into pools of Delta/Theta and Beta.
Wahbeh et al. used a similar stimulation time for their study yet
failed to note any entrainment, which suggests the length of
stimulation may not be a factor. Therefore it may be possible the
higher vigilance noted in Lane’s study was due to the use of both
an interaction between the 16 and 24 Hz frequency cycling
binaural beats. Secondly, the tasks used to measure vigilance were
not identical and may have tapped into difference cognitive
This study used reaction time as an analogue for vigilance, as it
was thought that those who are more engaged would be more
likely to respond faster to a target than those who are not. Correct
versus incorrect measures were recorded, however all included
participants successfully identified the target stimuli 100% of the
time, suggesting the task may have been too easy. Lane et al. used
target hits to non-target false alarm key presses as their measure,
which it could be argued may not just reflect vigilance but also the
ability to inhibit irrelevant stimuli. Future studies may wish to
design a task that adequately measures both in order to elucidate.
Entrainment of Theta frequency as evidenced by increased
power spectral density was not observed in this study. Additionally
increased Beta power during the stimulation period was also not
observed. These results differ from those found by Brady et al.,
however support those found in the follow up study by Stevens et
al. and Wahbeh et al. In contrast, Karino et al. found increased
Theta components, however this study used event related
presentations to elicit alterations in cortical frequencies.
No direct differences between personality traits and cortical
power through binaural beat stimulation, or correlates between
the two were detected. This did not support the results of Stough
et al., who found that using photic stimulation at Beta and Theta
frequencies produced higher overall cortical entrainment in those
who scored higher in O and C, while A was associated with
increased Theta activity in the left temporal-central area. The
obvious answer for these differences would be the unlike methods
of attempting entrainment, as photic driving uses pulses of light
presented at a steady state in order to generate similar frequency
neuronal firing where as in this study steady state binaural beats
While several studies have used binaural beats in conjunction
with photic driving into order to generate psychological effects; for
a review see  there has yet to be any studies examining
Table 6. Theta Cortical Power Spectral Density by Personality
Trait, Trait Score and Condition.
Power (mV) Mean (S.D.)
Condition Low AverageHigh
Neuro Theta Control 50.00 (8.25)43.62 (9.99) 42.40 (8.69)
Neuro Theta Experimental50.64 (12.05) 40.75 (10.26)45.40 (10.86)
Extra Theta Control45.82 (4.92) 44.68 (10.10)47.21 (10.86)
Extra Theta Experimental45.43 (9.55)44.39 (13.59)44.37 (8.79)
Open Theta Control 45.68 (9.39)45.25 (9.36) 44.59 (13.12)
Open Theta Experimental 45.30 (16.31) 44.55 (11.76)43.40 (12.78)
Consc Theta Control48.37 (10.74) 43.92 (9.61) 51.87 (6.90)
Consc Theta Experimental61.30 (2.87)43.31 (2.88) 49.97 (11.55)
Agree Theta Control42.18 (8.81)44.53 (9.81)51.72 (6.76)
Agree Theta Experimental42.97 (10.02)43.66 (12.51)50.88 (12.67)
Table 4. Means and Standard Deviations of Cortical Power
Spectral Density (in mV) by Condition.
ConditionPower Mean (S.D.)
Beta Control15.70 (1.07)
Beta Experimental 16.55 (1.24)
Theta Control 45.23 (1.71)
Theta Experimental44.52 (2.20)
Table 5. Beta Cortical Power Spectral Density by Personality
Trait, Trait Score and Condition.
Power (mV) Mean (S.D.)
Neuro Beta Control 13.79 (1.37)16.88 (1.38)15.43 (3.71)
Neuro Beta Experimental 13.44 (1.15)18.31 (1.36)16.49 (4.99)
Extra Beta Control14.00 (1.79) 16.06 (1.45)15.48 (1.40)
Extra Beta Experimental14.40 (2.77) 17.36 (2.77)14.67 (0.86)
Open Beta Control18.46 (1.27) 14.35 (1.33) 19.70 (2.34)
Open Beta Experimental18.51 (1.78) 15.29 (1.54) 21.01 (3.20)
Consc Beta Control 9.73 (4.80)16.72 (1.19) 12.36 (1.47)
Consc Beta Experimental 10.72 (3.58) 17.58 (1.43)12.96 (1.22)
Agree Beta Control 15.41 (2.60) 16.12 (1.32) 13.4 (1.37)
Agree Beta Experimental 14.87 (1.97)17.21 (1.56) 13.83 (1.01)
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delineation between the two, especially for electrophysiological
responses. That no significant differences were found in Beta or
Theta power in any division of the cortex or for any personality
trait was unexpected. It may be that this study simply failed to
expose participants to binaural beat stimulation for long enough.
There has been a suggestion that at least five minutes is required
for observation of entrainment to occur, however the authors of
this study were unable to locate the abstract or article that made
this claim  thus not able to verify it. Other studies tend to use
periods of up to 30 minutes for binaural stimulation, however
given the contradictory results discussed above and that event
related studies  managed to generate electrophysiological
increases in Theta frequency using binaural beats in a period of
2 seconds, the time of presentation is not thought to be an issue.
The task itself may have contributed to an inability to observe
cortical frequency alteration using binaural beats, at least in the
Theta range, due to the suggestion Beta activity is related to visual
processing, especially in the temporo-parietal areas  and as
such may have masked increases in Theta. However some 
have used visual stimuli and also found evidence of frequency
alteration, at least using an event related design. As such a task/no
task paradigm might be investigated in the future. Examining the
mean frequency power over the two-minute presentation blocks
may have prevented detection of entrainment. If entrainment only
occurred in very brief periods in the experimental condition rather
than presumed sustained increases at the target frequencies, this
study would not have been able to detect it. Instead, a frequency
over time analysis is strongly recommended in future examinations
to rule out the possibility of entrainment in sporadic brief events.
A final consideration is the use of pink noise, overlaid music or
sound, to generate some sort of effect. One study  compared
music with an embedded binaural beat to music without one and
generated a significant decrease in pain medication both during
and after an operation, however the study was not controlled as
participants were allowed to choose their own music. Also, other
studies using pink noise [8,18] have not detected entrainment, but
have found psychological changes previously discussed. Compar-
ing pink noise with a binaural beat, without and a control and
subsequent effects on electrophysiological and psychological
factors may be of interest.
In conclusion, this study aimed to examine if binaural beats
were able to alter psychological processes and entrain cortical
frequencies. Furthermore it aimed to examine if personality traits
modulated entrainment. No statistically significant changes or
relationships were detected between binaural beat stimulation at
Beta and Theta frequencies and white noise control conditions in
any personality trait, the vigilance task or EEG power spectra
analysis. These results suggest that relatively short presentation
steady state binaural beat stimulation at Beta and Theta
frequencies are insufficient to generate entrainment and in turn
this lack of entrainment does not seem to be related to personality
traits. Additionally it appears that short presentation stimulation of
binaural beats is ineffective at altering vigilance.
The authors would like to thank Emily Miller for assisting with formatting.
Conceived and designed the experiments: JC JK PG KB AC MH.
Performed the experiments: PG KB AC MH. Analyzed the data: JC JK
PG. Contributed reagents/materials/analysis tools: JK. Wrote the paper:
JC JK PG.
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Table 7. Correlations of Beta, Theta Experimental and Control Frequency Binaural Beat Cortical Powers in Divided Cortical Areas
and NEO Personality Traits.
NeuroExtra Open ConscAgree
Condition BetaBCon Theta TCon Beta BCon Theta TCon BetaBCon Theta TCon Beta BCon Theta TCon BetaBCon Theta TCon
FrontalLeft 0.12 0.04
20.23 20.25 20.10 20.04 0.040.02
20.07 0.05 0.05 0.27
20.24 20.01 0.22
20.15 0.23 0.19
20.24 20.27 20.23 20.15 0.12 0.04
20.17 0.020.05 0.10
20.22 0.07 0.26
CentralLeft 0.14 0.07
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20.02 20.01 20.30
Temporal Left0.23 0.12
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20.10 20.37 20.06 20.04 0.040.13
20.18 20.09 0.05
20.20 20.26 20.22 20.19 0.160.32
20.21 20.02 0.06 0.08
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20.13 0.09 0.05
20.20 20.09 0.07
*=Significant to 0.05 (Two tailed).
**=Significant to 0.01 (Two tailed).
Note: Neuro=Neuroticism, Extra=Extraversion, Open=Openness to Experience, Consc=Conscientiousness, Agree=Agreeableness, BCon=Beta Control, TCon=Theta
Binaural Beat Stimulation, EEG and Personality
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