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It is natural to assume that the fine-grained and highly accurate spatial information present in visual experience is often used to guide our bodily actions. Yet this assumption has been challenged by proponents of the Two Visual Systems Hypothesis (TVSH), according to which visuomotor programming is the responsibility of a "zombie" processing stream whose sources of bottom-up spatial information are entirely non-conscious (Clark, 2007, 2009; Goodale & Milner, 1992, 2004a; Milner & Goodale, 1995/2006, 2008). In many formulations of TVSH, the role of conscious vision in action is limited to "recognizing objects, selecting targets for action, and determining what kinds of action, broadly speaking, to perform" (Clark, 2007, p. 570). Our aim in this study is to show that the available evidence not only fails to support this dichotomous view but actually reveals a significant role for conscious vision in motor programming, especially for actions that require deliberate attention.

This paper proposes a novel experimental approach that would help to determine whether perspectival shapes, such as the elliptical profile of a tilted plate or coin, are part of perceptual experience. If they are part of perceptual experience, then it should be possible to identify these shapes simply by attending appropriately to them. Otherwise, in order to identify perspectival shapes they must first be constructed in the visual imagination. We propose that these accounts of perspectival identification can be tested by measuring the interference between visual and verbal working memory load, respectively, and the identification of perspectival shapes in the appearance of a 3D object. * Both authors contributed equally to this work. 1 We use "perspectival shape" instead of "apparent shape" since there is a clear sense in which the object shape is also apparent: e.g. the white face of the cube in Figure 1 clearly looks square, and the billiards rack looks like an equilateral triangle, etc. 2 The properties of distance and slant (in 3D) are viewer-relative but do not count as perspectival properties for our purposes. That is because we consider them instead to be part of our experience of the 3D world around us. For example, the rim of a cup, when viewed obliquely, looks circular, slanted in depth, and located some distance away. What we call "perspectival properties" are (roughly) those that a painter would draw on a 2D canvas, i.e., those that 3D objects project onto a flat medium, perpendicular to the line of sight. These do not include 3D slant and distance.

How do we recognize identities between seen shapes and felt ones? Is this due to associative learning, or intrinsic connections these sensory modalities? We can address this question by testing the capacities of newly sighted subjects to match seen and felt shapes, but only if the subjects can see the objects well enough to form adequate visual representations of their shapes. In light of this, a recent study by R. Held and colleagues fails to demonstrate that their newly sighted subjects' inability to match seen and felt shape was due to a lack of intermodal connections rather than a purely visual deficit, as the subjects may not have been able visually to represent 3D shape in the perspective-invariant manner required for intermodal matching. However, the study could be modified in any of several ways to help avoid this problem.