Rapid Learning and Long-term Memory in the Speech-to-song Illusion

Abstract

The speech-to-song illusion is a perceptual transformation in which a spoken phrase initially heard as speech begins to sound like song across repetitions. In two experiments, we tested whether phrase-specific learning and memory processes engaged by repetition contribute to the illusion. In Experiment 1, participants heard 16 phrases across two conditions. In both conditions, participants heard eight repetitions of each phrase and rated their experience after each repetition using a 10-point scale from “sounds like speech” to “sounds like song.” The conditions differed in whether the repetitions were heard consecutively or interleaved such that participants were exposed to other phrases between each repetition. The illusion was strongest when exposures to phrases happened consecutively, but phrases were still rated as more song-like after interleaved exposures. In Experiment 2, participants heard eight consecutive repetitions of each of eight phrases. Seven days later, participants were exposed to eight consecutive repetitions of the eight phrases heard previously as well as eight novel phrases. The illusion was preserved across a delay of one week: familiar phrases were rated as more song-like in session two than novel phrases. The results provide evidence for the role of rapid phrase-specific learning and long-term memory in the speech-to-song illusion.