The role of spectral factors in the occurrence of the gap transfer illusion

Abstract

When a long ascending frequency glide with a gap at the temporal middle and a short continuous descending glide cross at their central position, observers report that the gap belongs to the short glide in spite of the physical position of the gap. This phenomenon is called the gap transfer illusion. We employed multiple‐component crossing patterns and systematically varied the spectral slopes or formants of glides. In patterns that contained glides consisting of three harmonic components, the gap transfer illusion occurred when the crossing glides had equal spectral slopes, while the illusion was inhibited when the crossing glides had different spectral slopes. In patterns that contained 25 harmonic components representing formants of Japanese vowels, the gap transfer illusion took place only when the crossing glides had the same formants. Although Nakajima et al. (2000) explained the gap transfer illusion in terms of the proximity of onsets and terminations, the present results show that it is also important to consider the role of spectral factors. [Work supported by JSPS and 21st Century COE, Kyushu University.]