Illusory transformation from speech to song.

An illusion is explored in which a spoken phrase is perceptually transformed to sound like song rather than speech, simply by repeating it several times over. In experiment I, subjects listened to ten presentations of the phrase and judged how it sounded on a five-point scale with endpoints marked "exactly like speech" and "exactly like singing." The initial and final presentations of the phrase were identical. When the intervening presentations were also identical, judgments moved solidly from speech to song. However, this did not occur when the intervening phrases were transposed slightly or when the syllables were presented in jumbled orderings. In experiment II, the phrase was presented either once or ten times, and subjects repeated it back as they finally heard it. Following one presentation, the subjects repeated the phrase back as speech; however, following ten presentations they repeated it back as song. The pitch values of the subjects' renditions following ten presentations were closer to those of the original spoken phrase than were the pitch values following a single presentation. Furthermore, the renditions following ten presentations were even closer to a hypothesized representation in terms of a simple tonal melody than they were to the original spoken phrase.