Type 2 blindsight and the nature of visual experience.

Summary

Type 2 blindsight patients have some residual awareness after V1 damage, but their visual experience lacks particularity, transparency, and fine-grainedness often thought essential to normal vision. This challenges the idea that veridical visual experience must be a perceptual relation to external objects. The paper also argues that attentional modulation in type 2 blindsight shows that changes in appearance due to attention are consistent with visual phenomenology arising from content.

Study at a glance

Abstract

Blindsight is a kind of residual vision found in people with lesions to V1. Subjects with blindsight typically report no visual awareness, but they are nonetheless able to make above-chance guesses about the shape, location, color and movement of visual stimuli presented to them in their blind field. A different kind of blindsight, sometimes called type 2 blindsight, is a kind of residual vision found in patients with V1 lesions in the presence of some residual awareness. Type 2 blindsight differs from ordinary visual experience in lacking the particularity, transparency and fine-grainedness often taken to be essential to visual experience, at least in veridical cases. I argue that the case of type 2 blindsight provides a counterexample to the view that these characteristics are essential to veridical visual experience and that this gives us reason to resist the view that visual experience is essentially a perceptual relation to external objects. In the second part of the paper I argue that the case of type 2 blindsight yields important insights into the effects of attentional modulation on perceptual content and that cases of attentional modulation of appearance are not at odds with the view that the phenomenology of visual experience flows from its content.

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