Change Blindness, Representations, and Consciousness: Reply to Noë
Daniel J. Simons, University of Illinois, Champaign, IL, USA
Ronald A. Rensink, University of British Columbia, Vancouver, BC, Canada.

Trends in Cognitive Sciences, 9:219. 2005.   [pdf]

Our recent opinion article [1] examined what change blindness can and cannot tell us about visual representations. Among other things, we argued that change blindness can tell us a lot about how visual representations can be used, but little about their extent. We and others found the 'sparse representations' view appealing (and still do), and initially made the overly strong claim that change blindness supports the conclusion of sparse representations [2,3]. We wrote our article because change blindness continues to be taken as evidence for sparse--or even absent--representations, and we used O'Regan and Noë's influential paper [4] as an example. However, as has been noted for some time [5-8], this conclusion is logically flawed: lack of ability need not be caused by a lack of representation.

In his letter [9], Noë agreed that change blindness does not logically require sparse representations, but also claimed that the non-representationist view 'does a better job of explaining' change blindness. And, he argued that 'the existence of detailed internal representations does not (and could not) explain visual consciousness.' His letter also implied that we had leapt to a non-representationist conclusion based on evidence for change blindness. However, we never abandoned the idea that representations underlie our conscious experience even though we did argue for sparse representations. In fact, we have argued for ways in which representations do underlie awareness [10]. We believe that visual representations are necessary to explain some aspects of conscious experience. For example, people do detect most changes eventually, and conscious change detection requires conscious use of representations. If, according to the non-representationist view, change blindness occurs because representations do not contribute to awareness, then conscious change detection should be impossible.

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