Asymmetries for Ameslan handshapes and other forms in signers and nonsigners.

Much recent research has addressed the question of cerebral asymmetry in the perception of American Sign Language (Ameslan). The question has, of course, been prompted by the traditional characterization of the left hemisphere as specialized for language and the right for visuospatial or nonlinguistic functions. Since Ameslan carries a complexity and regularity analogous to that of spoken languages into the visual modality, the issue has been posed as one pertinent to the study of cerebral specialization in general. However, since several studies have demonstrated left-hemisphere advantages for nonlinguistic forms (Bever & Chiarello, 1974; Patterson & Bradshaw, 1975) and since others have shown right-hemisphere linguistic capacities (for a review, see Searleman, 1977), the question of asymmetries in the perception of sign language is by no means clear-cut. Indeed, variability of results in this domain have been extensively documented by Poizner and Battison (in press) and Poizner, Battison, and Lane (1979), and lend force to the notion that the study of hemisphere specialization in sign is complex. Our point in this note is to compare two previous studies (Phippard, 1977; Poizner & Lane, 1979) with our own, presented here for the first time. All were conducted independently at about the same time, and are very similar in design. Yet the results are somewhat different. To facilitate discussion, we present our study first.