Science Questions

Why would our eyes have developed to take in more information than our brains can process? Secondly, if we only use about five per cent of our brain, is the rest a load of useless mess? What would happen if you stimulated the unused portions? Bradley in California

The eyes are connected to the visual apparatus in the brain, and collect information for the brain to process. If your eyes were going to do all the filtering and processing of information, you'd have to have the brain inside the eye. Since that's not the way that we've evolved, the eye just takes in the information and the brain does the processing. As for humans only using 5% of the brain, I think any neuroscientist would say that this isn't true. Brains are very expensive to maintain and use a large proportion of the body's energy. Evolution is also known as being very frugal, so if we didn't need to have all the parts of the brain, then we wouldn't have them. Although different parts of the brain are active at different times, if you took away any part of it, you'd end up with a profound disability. If you stimulate a person's brain, you will become conscious of whatever process that part of the brain controls. You can do this by using trans-cranial electromagnetic stimulation (TCMS). To do this you take a big magnet shaped like the number eight and hold it over someone's skull. You can make the bit of the brain it's held over become active. You can make people move their arms and say things when they don't want to.

December 2005