If you have ever seen the film Limitless, or trailers for the new film 'Lucy', you may have heard the idea thrown around that humans only use 10% of their brain. The idea behind this is that we only have 'access' to a portion of our brains, with the rest being somehow locked away, preventing us from fulfilling our true potential. In films like 'Lucy' where the protagonist then gains access to a greater proportion of the brain, they end up being able to think super quickly about high level abstract concepts, to remember virtually everything they've ever seen or read, and often to perform telekinetic abilities like mind control and levitation.
Before we go any further I'd like to rule out the telekinesis. Sad though it is, there is no reason to suspect that our brain harbours the secret ability to levitate things or communicate telepathically. There's no scientific mechanism through which such an event would be likely to occur, and there are no examples of it happening anywhere else in nature.
So even if we were only using 10% of our brains, we probably wouldn't be able to float if we could amp it up to 100%.
But more to the point… the whole 10% thing is nonsense.
Where the Idea Comes From
The whole idea that we only use 10% of our brains – a belief shared by 65% of Americans – is based on a misunderstanding of the science. The brain is actually incredibly efficient when it comes to the brain areas it develops and it has to be seeing as there is barely enough room in the skull for it to fit (one of the reasons it's so wrinkly (with all those gyri and sulci)). If you look at any photos of brain imaging studies – which show the areas of the brain that are being used at any given time – you will see that only certain portions are ever lit up. This could understandably lead to confusion, but the point is that the brain only uses certain areas at any given time because those are the areas it needs at those points. You use every part of the brain yes, just not at the same time – there would be no benefit to that it would simply seem like a huge amount of 'noise'. There is no 'area' that doesn't get used.
What psychologists have said though is that we only use a portion of our potential. That is to say that we could develop greater intelligence with the right training, diet and regimen. It's possible that your IQ could be much higher were you to actively work on improving it in the same manner as a bodybuilder improves their body.
So you do have untapped potential after all. It's just the 10% thing that's the complete myth…