The octave illusion in relation to handedness and familial handedness background.

The octave illusion is produced by a dichotic sequence of tones that alternate in frequency between 400 and 800 Hz, such that when the right ear receives 400 Hz the left ear receives 800 Hz; and vice versa. Most listeners obtain the illusion of a single high tone in one ear alternating with a single low tone in the other ear. Further, most right-handers hear the high tone on the right and low tone on the left. The present study examined localization patterns in this illusion as a function of handedness and also of familial handedness background. The effect of handedness was highly significant: the tendency to hear the high tone on the right and the low tone on the left was lower among mixed handers and left-handers than among right-handers. The effect of familial handedness background was also highly significant: the tendency to hear the high tone on the right and the low tone on the left was lower among those with a sinistral familial background than among those with a purely dextral familial background. These findings are discussed in relation to the hypothesis that perception of the illusion serves as a reflection of the direction of cerebral dominance in most individuals.