Gesture - Volume 7, Issue 3, 2007

Children diagnosed with an Autistic Spectrum Disorder (ASD) are frequently thought to be incapable of using communicative gestures. When children with an ASD undertake motor actions — other than practical actions (such as direct manipulation of the physical environment) — these are often taken to be either impaired relative to control groups or symptomatic of the child’s pathology. Drawing on videotaped data of children with an ASD interacting in home and school settings, we examine adult–child interactions in which children repeatedly tap items that are presented to them (for a response). We show how these actions are systematically placed at just those points where it is appropriate for the child to provide an answer (or candidate solution) to the adult’s question but before the child has completed it. Thus by investigating the sequential context in which actions of this sort are placed we can better appreciate the interactional work they undertake and the extent to which they are communicative gestures rather than either being interactionally irrelevant or symptomatic of an underlying pathology.

We studied if and when people detect the beginning of a gesture, in our case a sign in Sign Language of the Netherlands (SLN), by presenting movie fragments consisting of sequences of rest positions, fidgets, and signs to deaf signers, hearing signers and non-signers. Participants were instructed to respond as soon as they saw that a SLN sign had begun. All participants showed themselves highly capable of responding to sign beginnings. Signs that are two-handed, performed in signing space, have a highly marked hand shape, and contain path movement were discriminated best. Considering a sign as having a preparation, a stroke, and a recovery, response times showed strong clusters around 500 milliseconds after the beginning of sign preparation, or 200 ms after the onset of the stroke. The non-signers needed more time before responding; deaf signers took more time than hearing signers. Response time was influenced by three factors (shorter for signs that have a highly marked hand shape, are one-handed, and are preceded by fidgets). The results show that it is possible for people to discriminate fidgeting and signs based on appearance, even if one does not know sign language. No single feature of the movement appears necessary to detect the beginning of a sign. In most cases visual information available up to an early stage of the stroke is sufficient but in some cases the information in the preparation is enough.

A previous study among European-Americans (McClave, 2000) observed that particular forms of head movements occur in specific communicative environments. The present study investigates whether any of the form–function relationships observed in the original study are cross-cultural. The database consists of seven hours of videotaped spontaneous conversations in Arabic, Bulgarian, Korean, and African-American Vernacular English. This study suggests that head movements are used for semantic, discourse, and interactive functions in these four languages from three genetically unrelated language families.1 Identical head movements occur in three environments across all four cultures: lateral movements co-occur with expressions of inclusivity, the head changes position for each item on a list, and the head orients toward a specific location selected by the speaker when referring to non-present or abstract entities. Head movements function as speaker backchannel requests in each culture as well, but the particular form of movement corresponds to the culture’s head motion for affirmation.