When the brain's main vision area, called V1, is destroyed, people lose conscious sight. Yet some can still point to, guess or avoid things in front of them far better than chance. Researcher Lawrence Weiskrantz and colleagues named this blindsight in 1974.
Truth label: Established. Strong evidence and broad agreement among experts.
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The hallway test
A man known as TN lost V1 on both sides of his brain after two strokes. Researchers asked him to walk a cluttered corridor without his cane. He made it to the end without bumping into anything, even stepping around a bin.
Feeling without seeing
Some patients can guess the emotion on a face they cannot see, and their own face muscles subtly mirror it. This is called affective blindsight.
The open question
A few researchers argue blindsight is really very faint conscious vision, not vision without awareness at all. Most of the research treats it as a real gap between seeing and knowing you see.
Learn
- First noticed in war. After the First World War, neurologist George Riddoch described soldiers with head wounds who could see moving objects but not still ones. Some still call this Riddoch syndrome.
Test yourself
Damage to which brain area causes blindsight?
The primary visual cortex (V1). Blindsight follows damage to V1, the main visual area at the back of the brain.
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