How Blind Are We? (We have eyes, yet we do not see)

http://www.sciam.com/article.cfm?chanID=sa017&articleID=000B5245-6805-128A-A3C683414B7F0000

A study conducted by Daniel J. Simons, now at the University of Illinois, and Christopher F. Chabris of Harvard University shows that we may not see the world as well as we think. We think of our eyes as video cameras that make a flawless recording of the world around us, but, as Simons and Chabris discovered, we actually take in very little information at a glance.The experiment was set up at a basketball game, and the audience was told to count the number of times each player made a pass to another person during a 60-second period. It was hard to concentrate on the ball while it was moving so quickly, but suddenly someone dressed in a gorilla suit ambled across the floor. He walked through the players, turned to face the viewers, thumped his chest and left. Astonishingly, fifty-percent of the people fail to notice the gorilla.

Researchers refer to this effect as "inattentional blindness" or "change blindness". Our brain is constantly trying to construct meaningful narratives from what we see. Things that do not quite fit the script or that are not relevant to a particular task occupying our interest are completely wiped from consciousness. (Whether such deleted information is nonetheless processed unconsciously has yet to be investigated.) An example of how the brain's running narrative can interfere with perception is the children's game "spot the difference". The two images are similar enough that the brain assumes they must be identical; it takes minutes of careful inspection to locate the differences.

The value of having an underlying brain "story" becomes clear when you realize how jumbled sensory inputs can be. As you look at the room around you, the image on your retina is jumping rapidly as various parts of the scene excite different bits of retina, but the world appears stable. Researchers used to believe that the experience of having an unbroken view was created entirely by the brain sending a copy of the eye movement command signals originating in the frontal lobes to the visual centers. The visual areas were thought to be "tipped off" ahead of time that the jumping image on the retina was caused by eyes moving and not by the world moving.

Jonathan Miller, an opera director in London, did an independent observation of this effect in the early 1990's. In this observation, he turned his television set upside down and turned off the volume. He stood slightly to the side of the set, looking at the screen with his peripheral vision and noticed sudden, jarring changes and visual jolts. While viewing the broadcast with the TV right side up and at normal volume, the cuts and pans of the camera flowed smoothly and seamlessly into one another and Miller did not even notice them. Even when the scene switched, say, from one talking head to the other as they alternate in conversation, he did not see a head transforming or morphing from one to the other as his mind alternated between each of the two speakers. Instead the experience is of vantage point shifting.

What is going on in this experiment is that when the TV is right side up and you can hear the sound, the brain can construct a sensible narrative. The cuts, pans and other changes are simply ignored as irrelevant, however gross they might be physically. In contrast, when the scene is upside down or viewed with peripheral vision and the sound off, it is hard for the brain to make meaningful sense out of what the visual centers perceive, so you start to notice the big changes in the physical image. This effect is also true for your entire life's experiences.

Yet another experiment was conducted in 1992 by Colin Blakemore, now chief executive of the Medical Research Council in London. Blakemore used three abstract, colored shapes: a red square, a yellow triangle and a blue circle. He left this frame up for two seconds, then replaced it with the same three shapes, which were each shifted in position by a small degree. The audience observed that all three appeared to flicker or "glitch" slightly. Blakemore was astonished when the majority of the audience didn't even notice when he swapped the circle with a square. Even with three simple objects, we experience sensory overload and change blindness.



It is so amazing that the most complex and mysterious creation in the world, the brain, does not have the ability the comprehend all things around you. With the gorilla experiment we learn that while focusing intently on one subject, we may fail to recognize the most obvious obscurities of nature. In Miller's television observation we discover that our minds can smooth together carema angles and changes, but only depending on our vantage point. I thought, as a whole, this article was very thorough and proved its theory many times by using effective experiments. I was impressed with the amount of research and time scientists put into this theory, but I'm also blown-away at the fact that only God can fully comprehend this matter, no matter how technologically advanced we become.