Individual Differences in Perception of the Speech-to-Song Illusion AreLinked to Musical Aptitude but Not Musical Training

In the speech-to-song illusion, certain spoken phrases are perceived as sung after repetition. One possible ex-planation for this increase in musicality is that, as phrases are repeated, lexical activation dies off, enablinglisteners to focus on the melodic and rhythmic characteristics of stimuli and assess them for the presence ofmusical structure. Here we tested the idea that perception of the illusion requires implicit assessment of me-lodic and rhythmic structure by presenting individuals with phrases that tend to be perceived as song whenrepeated, as well as phrases that tend to continue to be perceived as speech when repeated, measuring thestrength 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 per-ceived the illusion more strongly were proficient in several musical skills, including beat perception, tonalityperception, and selective attention to pitch. Thesefindings support models of the speech-to-song illusion inwhich experience of the illusion is based on detection of musical characteristics latent in spoken phrases