Blindsight

What do you think would happen if your occipital lobes were damaged? Back in the 1970s, most scientists and physicians would have said, “You would become blind.” It turns out that the answer is more complicated than that.

Unconscious Sight?

When he was 8 years old, Graham Young from Oxford, England, was injured in a bicycle accident. Afterward, he reported that parts of his vision were gone. He told his doctors that he could no longer see anything to the right of his center of vision with either his left or right eye. The left side of his visual field in both eyes was normal. Although he said that he would sometimes walk into objects to his right because he couldn’t see them, when tested fifteen years later, an optician discovered that Mr. Young seemed to respond to visual movements in his “blind” area.

 

Graham Young was put into contact with psychologists Larry Weiskrantz and Elizabeth Warrington, who had worked previously with a person (known as DB) who seemed to have a similar ability to see despite blindness. DB could report shapes, colors, movement, and the orientation of objects despite claiming that he could see nothing. He said that he was guessing, but he was usually right about colors and shapes, and other characteristics of the objects.

Before we go on, please take a moment to theorize about what might be going on with Graham Young and DB.

People with blindsight have been tested for their ability to detect color differences, brightness changes, discriminate between various shapes, as well as track movement. Critically, people with blindsight have the conscious experience of blindness, often feeling like they are guessing on visual tasks despite their high level of accuracy.