Individuating in the dark: Diagrammatic reasoning and attentional shifts

This inquiry first identifies signs whose representamen are inherently visuo-spatial (namely, Index) supplying rationale for dicisign status, then demonstrates how such results in difficulties without visual access. Virtually all of Peirce's illustrations of Index surface in the visual modality: weathercock, clock hands (1903: EP 2: 274), pointing finger, smoke. Experimental findings from blind and sighted children suggest the less effective nature of semiotic alternatives to visual indexes (tactual landmarks), to disambiguate objects in other modalities. In short, delays in use of index leave blind children vulnerable to protracted means to individuate, and ultimately to reduced participation in joint attentional ventures.