TN, a middle-aged man from Switzerland suffered two strokes several years ago. The strokes caused extreme damage to his visual cortex, the part of the brain primarily responsible for vision. The catch? He can still see. Not Exactly Rocket Science reports that under certain circumstances TN has been able to accurately identify the emotions playing across people’s faces and also indicate which direction a metal bar was pointing (horizontal, vertical, or diagonal).
But TN caused the biggest brouhaha when he completed an obstacle course (you can watch the video here). Scientists were astounded when TN successfully navigated a length of hallway littered with stands, books, files, and boxes, without touching a single object. The only person who remained unperturbed was TN. For, TN’s condition, “blind sight”, allows him to “see” certain things without the awareness that he is seeing them. In other words, he sees unconsciously. So after he made his way down the hall, he had no idea that he had avoided numerous obstacles.
NPR notes that scientists will use TN’s case to study consciousness. They can compare the way TN’s brain works when he unconsciously sees to the way a person’s brain works when s/he consciously sees. By analyzing the difference they hope to learn more about how consciousness arises and how it functions.
TN’s blind sight raises questions about the centrality of consciousness and the unity of the homo sapien. Am I an unsteady alliance of bio-machines that has a particular part (consciousness) that makes me think I am one? What is your take on TN and consciousness?