Identification and discrimination of handshape in American Sign Language

Lane, Boyes-Braem, and Bellugi (1976) suggested that American Sign Language (ASL) was perceived according to distinctive features, as is the case with speech. They advanced a binary model of distinctive features for one component of ASL signs, handshape. To test the validity of this model, three native users of ASL and three English speakers who knew no ASL participated in two experiments. In the first, subjects identified ASL handshapes obscured by visual noise, and confusion frequencies yielded similarity scores for all possible pairs of handshapes. Pairs that shared more features according to the model produced higher similarity scores for both groups of subjects. In the second experiment, subjects discriminated a subset of all possible handshape pairs in a speeded “same-different” task; discrimination accuracy and reaction times yielded a d’ and a d_s value, respectively, for each pair. Pairs that shared more features according to a slightly revised version of the model produced lower discrimination indices for both groups. While the binary model was supported, a model in which handshape features varied continuously in two dimensions was more consistent with all sets of data. Both models describe hearing and deaf performance equally well, suggesting that linguistic experience does little to alter perception of the visual features germane to handshape identification and discrimination.