Abstract
The ability to reach and grasp an object is accompanied by an innate experience of conscious access to the visual information supporting the response. However, actions can be performed in the absence of conscious visual awareness – a phenomenon attributed to the separate pathways supporting perceptions (i.e., ventral pathway) and actions (i.e., dorsal pathway). For example, reaching responses performed in a backward masking paradigm demonstrate speed-accuracy relations regardless of whether participants are 'aware' or 'unaware' of target size, whereas perceptual judgments require access to a conscious visual percept (Binsted et al. 2008: Proc Natal Acad Sci USA). The present study sought to determine whether a response requiring decoupled spatial relations between stimulus and response is mediated via the same 'unconscious' visual information as their target-directed counterparts. To that end, participants: (1) reported the size of target objects in 'no-mask' and 'mask' conditions (i.e., perceptual task), and (2) reached directly to (i.e., pro-pointing) and mirror-symmetrical (i.e., anti-pointing) to the same 'no-mask' and 'mask' targets. Results for the perceptual task showed that participants could accurately report the size of a target object in 'no mask' but not 'mask' trials. For the reaching task, results indicated that 'no mask' pro-pointing trials elicited reliable speed-accuracy relations, whereas 'mask' pro-pointing as well as anti-pointing (i.e., 'no-mask' and 'mask') did not. These results demonstrate that anti-pointing renders the structuring of a response via a conscious visual percept and that the top-down demands associated with response mediation influence the nature of the visual information supporting motor output.
