The Speech-to-Song Illusion is an auditory illusion that occurs when a spoken phrase is repeatedly presented. After several presentations, listeners report that the phrase seems to be sung rather than spoken. Previous work [1] indicates that the mechanisms—priming, activation, and satiation—found in the language processing model, Node Structure Theory (NST), may account for the Speech-to-Song Illusion. NST also accounts for other language-related phenomena, including increased experiences in older adults of the tip-of-the-tongue state (where you know a word, but can’t retrieve it). Based on the mechanism in NST used to account for the age-related increase in the tip-of-the-tongue phenomenon, we predicted that older adults may be less likely to experience the Speech-to-Song Illusion than younger adults. Adults of a wide range of ages heard a stimulus known to evoke the Speech-to-Song Illusion. Then, they were asked to indicate if they experienced the illusion or not (Study 1), to respond using a 5-point song-likeness rating scale (Study 2), or to indicate when the percept changed from speech to song (Study 3). The results of these studies suggest that the illusion is experienced with similar frequency and strength, and after the same number of repetitions by adult listeners regardless of age.

Introduction:Five studies examined the speech to song illusion, the verbal transformation effect, and the sound to music illusion in order to determine if they were distinct phenomena and to assess if they could be accounted for by a single perceptual/cognitive mechanism. Methods:In Study 1, word lists varying in length from 1 word (as often used to study the verbal transformation effect) to 4 words (as often used to study the speech to song illusion) were presented to participants for 4 minutes to investigate the percepts that were elicited. In Study 2 participants were asked to indicate YES/NO if they experienced the speech to song illusion when listening to word-lists modified by a vocoder. In Studies 3-5 participants were asked to click a button as soon as the shift in percept occurred from speech (or sound) to a music-like percept to assess the time-course of the speech to song (or sound to music) illusion.Results: Study 1 shows that the verbal transformation effect and the speech to song illusion elicit similar percepts. In Study 2 participants indicated that the speech-like stimuli elicited the speech to song illusion more than the noise-like stimuli. In Studies 3-5 similar time-courses were observed for the speech to song illusion and the sound to music illusion.Discussion: Previous, single-mechanism accounts of the speech to song illusion are discussed, but none of them adequately account for all of the results presented here. A new model is proposed that appeals to both a perceptual/"lower-level" mechanism and a cognitive/"higherlevel" mechanism.