Infants’ perception of transposed melodies

It has been suggested that infants are similar to adults in their perception of tone chroma, in the perceptual similarity of notes in octave relationships [Demany and Armand (1984)]. In music, note pitches are defined by height (frequency distance) and chroma (key). The current study further examines this question. Seven- to nine-month-old infants’ perceptions of transpositions of six-note tonal melodies were measured using an observer-based procedure. Once given a background melody subjects were trained to respond to an entirely different training melody and not to a simple transposition. Once that discrimination had been learned, transposed versions of the background melody were introduced. If infants perceive tone chroma as adults do, they should learn this discrimination more quickly for an octave transposition. In fact, infants learned to ignore a transposition by a fifth more quickly than transpositions by an octave. The implication is that infants found melodies that were transposed by a smaller distance in frequency as more perceptually similar to the background melody than they did for the octave transposition. A possible conclusion is that octave transpositions of whole melodies have special perceptual status for infants of this age range. [Work supported by NIDCD Grant No. DC00396.]