Organization in the Perception of Speech by Young Infants
Evidence is presented that 3- and 4-month-old infants are able to integrate two sounds with different sources and locations to form a coherent speech percept. Synthetic speech patterns were presented dichotically so that one ear received the third-formant transition appropriate for the syllable [da] or [ga], and the other car received the base, that is, the remaining acoustic information necessary for syllabic perception. Adults typically perceive these stimuli as a birdlike chirp at the ear receiving the transition and. depending on which transition is presented, as the syllable [da] or [ga] at the ear receiving the base. Infants discriminated the two dichotic patterns. They also discriminated them when the third-formant transitions were attenuated to the extent that infant listeners could not discriminate them when they were presented in isolation. The results support the contention that the infants integrated the two disparate sources of acoustic information into a coherent percept that is presumably phonetic in nature, and they are also consistent with the view that this organization arises from a specialized system for the perception of speech.