The nature and probable origin of binaural beats

Joseph Peterson
1916 Psychological review  
If two tone waves of slightly different pitch are conducted separately in tubes, one to each ear, it will be found that they beat. Beats of this kind are called binaural to distinguish them from beats produced by the operation of both tone waves in the same ear. A question of importance to auditory theory arises here: Are these two kinds of beats, binaural and monaural, really different in principle? Are binaural beats not due to some sort of conduction of the vibration series from one ear to
more » ... s from one ear to the other so that both waves really operate in each ear? At least three modes of such conduction from one side to the ear at the opposite side of the head are possible. Unless much care is taken in connecting the sound-tight tube to the meatus of the ear, vibrations may be communicated to the air external to the head and thus carried to the opposite ear as an ordinary air wave. As a second possibility the tone wave may go directly from the air in the meatus to the bones of the skull and thence to the liquids of the inner ear on the opposite side of the head. Finally, some of the middle ear structures, or even the liquids of the labyrinth, may communicate the wave to the bones of the skull by which they can be conducted to the opposite ear. It is conceivable, moreover, that under certain conditions all these means may be operative. . Evidence is not wanting to show that such cross-conduction of the wave is probable. It is well known that vibrations are effectively conducted to the labyrinth by the bones of 333
doi:10.1037/h0070767 fatcat:73rspaek3rbgzdisxyszyw4b2m