Although language practices must obviously be an empirical focus in sociocultural research, this article suggests that emphasis on the human body's material aspect has not revealed how, in particular communicative contexts, its ideational influence surpasses that of language. This article suggests that in the "social" semiotic, the body's function is primarily material because its activity does not alter a prevailing audio-temporal sign system. In the "spatial" semiotic, a context of activity in which a visual-spatial code is the principal means of expression, the mediational influence of the human body on perception and conception is clear. Incorporating qualitative data and drawing on research in biosemiotics, the author notes how spatially coded sign relations appear to guide the neuronal processes responsible for intersubjective understanding. The importance of intersubjectivity to cognitive development underscores the need to expand current conceptions of embodiment to include bodily activity in contexts of social "and" spatial signification. (Contains 2 footnotes.)