Infant Discrimination of Gestural Classes: Perceptual Precursors of ASL Acquisition

This research investigates the ability of 3.5-month-old hearing infants to discriminate between classes of gestures in American Sign Language (ASL). Perceptually, the classes differ in underlying movement dimensions, as reflected in adult similarity judgments (Poizner 1981 1983). Linguistically, the classes are used to mark different inflectional categories in ASL. Using a habituation-recovery paradigm, 36 infants were habituated to three tokens from one class. After reaching criterion, infants were presented with two new tokens: one a new member of the habituation set, the other a member of the previously unseen gestural class. Infants showed greater recovery to the new token from the unfamiliar class than they did to the new token from the familiar class. These results demonstrate that infant abilities to distinguish between classes of gestures parallel adult perceptual abilities as reflected in similarity ratings. They also indicate that, at four months, infants possess the prerequisite ability to classify gestures based on variations in movement in ways that correspond to inflectional distinctions in ASL.