The present paper studies how, in deictic expressions, the temporal interdependency of speech and gesture is realized in the course of motor planning and execution. Two theoretical positions were compared. On the "interactive" view the temporal parameters of speech and gesture are claimed to be the result of feedback between the two systems throughout the phases of motor planning and execution. The alternative "ballistic" view, however, predicts that the two systems are independent during the phase of motor execution, the temporal parameters having been preestablished in the planning phase. In four experiments subjects were requested to indicate which of an array of referent lights was momentarily illuminated. This was done by pointing to the light and/or by using a deictic expression (this/that light). The temporal and spatial course of the pointing movement was automatically registered by means of a Selspot opto-electronic system. By analyzing the moments of gesture initiation and apex, and relating them to the moments of speech onset, it was possible to show that, for deictic expressions, the ballistic view is very nearly correct . 0 1985 Academic Press, Inc The general issue addressed in this article concerns the synchronization of speech and gesture. More specifically the aim is to investigate how the frequently noted interdependence of speech and gesture is realized in the course of motor planning and execution. Do the two systems operate interactively, in the sense that mutual adaptation takes place during the phase of motor execution, or do they rather operate in a ballistic or independent fashion in so far as
Levelt et al. REF investigated this temporal interdependency of speech and gesture to compare two theoretical positions: the temporal structure could be either pre-planned before motor execution (ballistic view) or it could be a result of a recurrent feedback loop on the level of motor execution (interactive view).
Pointing and voicing in deictic expressions
Journal of Memory and Language
Psychology