Roles of temporal proximity between sound edges in the perceptual organization of veridical and illusory auditory events

At what level is the gap transfer illusion illusory?

“…The gap in Sound 1-3 is preserved perceptually, but in the shorter glide. Nakajima et al's (2014) Auditory Grammar explains this as follows (see also Nakajima et al, 2022;Remijn & Nakajima, 2005). The onset of the shorter glide and the offset just before the gap of the longer glide are mutually close in time, and there is enough sound energy to act as a filling between them, resulting an illusory tone made of an onset, a filling, and an offset.…”

“…If a 100-ms gap is cut out in the shorter glide (Sound 1-2), two successive short tones are perceived, separated by a gap. However, if a gap is cut out in the longer glide (Sound 1-3), it is still perceived as continuous, leaving the gap in the shorter glide ( Nakajima et al, 2022 )—the gap transfer illusion ( Nakajima et al, 2000 ). Sound 2 in Movie 2 is another version of this illusion.…”