Hand movement is a powerful medium for diagramming thought. With hand movements, the ordinary speaker routinely creates complex visual illustrations. These representations are visible and vivid during production and then, like speech, gone from the perceptual field. What is the link between the evanescent diagrammatic practices of gesture and visual representations of the historically enduring kind, such as iconographies, written texts, or printed diagrams? This chapter pursues the idea that the human body is a cognitive artefact both for those who inhabit it and for those who view it (Hutchins 1995, 2006). This is most vividly illustrated by focusing on hand gestures, perhaps the most salient contribution to the rich geography of cognition (Goodwin 2000a) constituted by bodily positioning, gaze, talk, and orientation to both the physical environment and the attentions of co-present others.

Different forms of iconographic or diagrammatic representation can have different cognitive consequences in problem-solving (Larkin and Simon 1987, Zhang 1997, Oestermeier and Hesse 2000). While this suggests implications for the broader study of culturally situated forms of visual representation, research on the role of external artefacts in cognition (e.g. Norman 1991, Hutchins 1995) has yet to connect with the ethnographic study of visual representations in non-literate and/or non-technological settings (but cf., for example, Wassmann 1997, Wilkins 1997, Green 2008 among other works on representation of spatial information).