Hand, mouth and brain. The dynamic emergence of speech and gesture
Abstract
We examine the embodiment of one foundational aspect of human cognition, language, through its bodily association with the gestures that accompany its expression in speech. Gesture is a universal feature of human communication. Gestures are produced by all speakers in every culture. They are tightly timed with speech. Gestures convey important communicative information to the listener, but even blind speakers gesture while talking to blind listeners, so the mutual co-occurrence of speech and gesture reflects a deep association between the two modes that transcends the intentions of the speaker to communicate. Indeed, we believe that this linkage of the vocal expression of language and the arm movements produced with it are a manifestation of the embodiment of thought: that human mental activities arise through bodily interactions with the world and remain linked with them throughout the lifespan. In particular, we propose that speech and gesture have their developmental origins in early hand-mouth linkages, such that as oral activities become gradually used for meaningful speech, these linkages are maintained and strengthened. Both hand and mouth are tightly coupled in the mutual cognitive activity of language. In short, it is the initial sensorimotor linkages of these systems that form the bases for their later cognitive interdependence.