Conscious Vision for Action Versus Unconscious Vision for Action?
Version of Record online: 7 MAR 2011
Copyright © 2011 Cognitive Science Society, Inc.
Volume 35, Issue 6, pages 1076–1104, August 2011
How to Cite
Brogaard, B. (2011), Conscious Vision for Action Versus Unconscious Vision for Action?. Cognitive Science, 35: 1076–1104. doi: 10.1111/j.1551-6709.2011.01171.x
- Issue online: 26 JUL 2011
- Version of Record online: 7 MAR 2011
- Received 19 December 2009; received in revised form 14 October 2010; accepted 6 December 2010
- Color processing;
- Dorsal stream;
- Enactive theory of perception;
- Shape processing;
- Unconscious vision;
- Ventral stream;
- Vision for action;
- Vision for perception
David Milner and Melvyn Goodale’s dissociation hypothesis is commonly taken to state that there are two functionally specialized cortical streams of visual processing originating in striate (V1) cortex: a dorsal, action-related “unconscious” stream and a ventral, perception-related “conscious” stream. As Milner and Goodale acknowledge, findings from blindsight studies suggest a more sophisticated picture that replaces the distinction between unconscious vision for action and conscious vision for perception with a tripartite division between unconscious vision for action, conscious vision for perception, and unconscious vision for perception. The combination excluded by the tripartite division is the possibility of conscious vision for action. But are there good grounds for concluding that there is no conscious vision for action? There is now overwhelming evidence that illusions and perceived size can have a significant effect on action (Bruno & Franz, 2009; Dassonville & Bala, 2004; Franz & Gegenfurtner, 2008; McIntosh & Lashley, 2008). There is also suggestive evidence that any sophisticated visual behavior requires collaboration between the two visual streams at every stage of the process (Schenk & McIntosh, 2010). I nonetheless want to make a case for the tripartite division between unconscious vision for action, conscious vision for perception, and unconscious vision for perception. My aim here is not to refute the evidence showing that conscious vision can affect action but rather to argue (a) that we cannot gain cognitive access to action-guiding dorsal stream representations, and (b) that these representations do not correlate with phenomenal consciousness. This vindicates the semi-conservative view that the dissociation hypothesis is best understood as a tripartite division.