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 domains.
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 were used.
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 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 
have not detected entrainment, but have found psychological changes previously discussed. Comparing 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.