An Auditory Phi Phenomenon

A possible auditory analogy of the visual phi phenomenon is a perceptual similarity, between sudden and continuous frequency transitions. Listeners heard 300‐msec tone bursts, each comprised of three parts: the first and third were steady frequencies, f1 and f2, and the second or middle part was either a 20‐msec glide or a silent gap of variable duration. Both the method of adjustment and the 2AFC paradigm were used to establish what gap duration yielded no or minimal discrimination between the two types of burst. Although perceptual identity is rarely reported, the jump‐versus‐glide discrimination is poorest when a 20‐msec glide is paired with a gap of 1–2 msec. The gap duration corresponding to such “similarity” decreases as the frequency difference between f1 f2 decreases. [Supported by PHS grant by NINDS.]