How Acoustic Salience Influences Infants’ Word Mapping

Young language learners have the challenge of discovering which sounds in their complex auditory environment form acceptable object labels. During early word learning infants demonstrate both flexibility and constraint regarding what sounds form meaningful distinctions. Through language experience they hone in on the sounds and sound patterns that are meaningfully relevant in their native language. In the current study, I investigated the role that acoustic salience plays in early word learning. Using the Switch paradigm, 14-month-old infants were taught to associate two novel labels that differed only in pitch contour to two novel objects. Results from previous discrimination studies were used to select two pairs of pitch contours. For half of the infants the two pitch contours were highly discriminable (Tone 1, level vs. Tone 3, dipping; Salient Condition). For the other half of the infants the labels were less discriminable (Tone 2, rising vs. Tone 3, dipping; Non-salient Condition). Importantly, pitch contour is not used contrastively in English, and none of the infants had experience with a tone language. Only infants in the Non-salient Condition successfully mapped the novel labels to objects. Results suggest that the criteria for what makes a word a good object label involves a confluence of factors, including, but not limited to the acoustic salience of the contrast.