Individual differences in perception of the speech-to-song illusion are linked to musical aptitude but not musical training.

In the speech-to-song illusion, certain spoken phrases are perceived as sung after repetition. One possible explanation for this increase in musicality is that, as phrases are repeated, lexical activation dies off, enabling listeners to focus on the melodic and rhythmic characteristics of stimuli and assess them for the presence of musical structure. Here we tested the idea that perception of the illusion requires implicit assessment of melodic and rhythmic structure by presenting individuals with phrases that tend to be perceived as song when repeated, as well as phrases that tend to continue to be perceived as speech when repeated, measuring the strength of the illusion as the rating difference between these two stimulus categories after repetition. Illusion strength varied widely and stably between listeners, with large individual differences and high split-half reliability, suggesting that not all listeners are equally able to detect musical structure in speech. Although variability in illusion strength was unrelated to degree of musical training, participants who perceived the illusion more strongly were proficient in several musical skills, including beat perception, tonality perception, and selective attention to pitch. These findings support models of the speech-to-song illusion in which experience of the illusion is based on detection of musical characteristics latent in spoken phrases. (PsycInfo Database Record (c) 2021 APA, all rights reserved).