Binaural Beats are an acoustic illusion, which can be perceiveable, when two sinusoids of two slightly different frequencies are presented using headphones. Based on Licklider et al. (1950) we investigate thresholds at which Binaural Beats are perceivable.
Binaural beats (BBs) arise from central auditory processing when two sinusoidal tones with slightly different frequencies are presented dichotically, resulting in the perception of a modulation corresponding to the interaural frequency difference (∆f ). Although BBs have been investigated extensively in psychoacoustic and applied research, reported effects remain inconsistent, possibly because the perceptual limits and reliability of BB perception are still insufficiently characterized. The present pilot study aimed to replicate and extend the classical work of Licklider et al. (1950) using contemporary psychoacoustic methods. Seven normal-hearing participants completed two BB detection tasks—a method-of-adjustment task and an adaptive staircase procedure—in a within-subject test–retest design. Carrier frequencies ranging from 125 to 1412 Hz were investigated, and the maximum detectable ∆f was determined for each carrier frequency. In addition, participants provided subjective comfort ratings for the individually adjusted BB stimuli at the just perceivable ∆f . Results revealed substantial interindividual variability and moderate test–retest consistency across both tasks. While carrier frequency influenced BB perception, the classical detection pattern reported by Licklider et al. was not consistently reproduced across participants. Subjective comfort ratings decreased with increasing carrier frequency, with higher frequency stimuli generally rated as less comfortable. These findings suggest that BB perception is less robust than often assumed and may depend strongly on listener-specific factors and prior experience. Improved psychoacoustic standardization and assessment of perceptual reliability may therefore be essential for future studies investigating cognitive or affective effects of binaural-beat stimulation.
Peer Reviewed Conference Proceeding
- Reproducibility and Reliability of Binaural Beat Perception (submitted)
Authors : Julia Schütze, Christoph Kirsch, Thomas P. Reber
