Chapter 1. “Blindsight”: Seeing Without Awareness

Short Description

Graham’s brain is of special interest to neuroscientists. When Graham was a child, he was hit by a car. As a result of the accident, he lost sight in the right visual field of both eyes.

Long Description

Graham’s brain is of special interest to neuroscientists. When Graham was a child, he was hit by a car. As a result of the accident, he lost sight in the right visual field of both eyes.

Twelve years after the accident, while undergoing an eye examination, investigators discovered that Graham could process visual information in both left and right visual fields. However, he is not aware of it. He demonstrates the phenomenon of blindsight.

Graham has experienced damage to his visual cortex. When moving lights are projected in his right field of vision, Graham reports he cannot see them. However, he can accurately report the direction in which they are moving. Blindsight is the condition in which people can respond to visual events without being aware of them.

Brain scans indicate that when Graham responds to the moving dots without being aware of them, a very primitive visual pathway is active. When he sees them, a new range of brain regions lights up. The parts of the brain underlying consciousness and our ability to communicate awareness are different and quite far removed from those that actually receive the sensory information.

Questions