Seeing What You Can't See

Sometimes people do things that appear to be the result of psychic abilities. One example is the curious case of blindsight. Blindsight occurs when an otherwise blind person can tell you where objects are located. This sure sounds strange and incredible. In fact, the first time blindsight was reported, neurologists thought the reports were fraudulent. So, how could a blind person tell you where something was located that they could not see? The answer lies in how vision is processed in the brain.

Vision starts with light entering the eye through the pupil and then being reflected by the lens to the retina at the back of the eye. The rods and cones in the retina convert the physical light energy into electrochemical energy that the brain understands. The message is then sent by way of the optic nerve to the primary visual cortex at the back of the brain. From the primary visual cortex, the message is sent to other areas in the brain that tell us what an object is and where it is located. As a result, we actually “see” with the brain. It wouldn’t make any sense that a blind person could tell you where an object is located if their primary visual cortex was damaged. So, what other explanation could there be?

When one of our sense is damaged, the brain often compensates by heightening the remaining other senses. Maybe blind people are able to get in touch with the “psychic” part of their brain after their vision loss. Is that the answer? Well, as it turns out, blindsight isn’t the result of psychic ability. The reason is that, in addition to the primary visual cortex, visual information travels to a midbrain structure called the superior colliculus. The superior colliculus receives messages that tell us where an object is located and whether it is moving. Blind people who have damage to the primary visual cortex, but not the superior colliculus, exhibit blindsight.

So you see, blindsight has a totally natural explanation. This shows that unexplained things can have natural explanations if we continue searching for them. If we stop looking for answers because we accept paranormal explanations, then we will stop learning and progressing. Some things may continue to stump scientists but that is no reason to accept paranormal explanations. By continuing to find out more about ourselves and the world, we get closer to discovering the true nature of reality. We should never become complacent about what we think we know, whether scientific or not. Natural explanations do not make the world a less interesting place. The fact that the brain can produce blindsight with sight impaired people is amazing.