Myths about the brain no. 2: We only use 10% of our brain

This idea has been floating around for a while and the most recent example I can think of is the main premise of the film "Limitless" with Bradley Cooper (which I thought was a good film. Unsatisfying end though but anyway). The main idea is that if you somehow unlock the ability to use the rest of your brain, you will suddenly develop incredible intelligence, abilities and learning prowess.

But if you look at the actual premise (that we only use 10% of our brain) it doesn't really make a whole lot of sense. What's the point of the other 90% if we never use it? Beyond that, there's an enormous amount of research that shows we use different parts of our brain for different processes and by the end of the day you will have used every part of your brain in some capacity or other. Think of the simple act of reading. You are processing all the little shapes on the paper or screen whilst at the same time your heart is beating, your lungs are breathing, your eyes are blinking, your foot may be twitching. These processes are controlled by different regions e.g. visual cortex for perceiving the words and the brain stem for maintaining homeostasis (through breathing, regulating blood pressure). We know that a variety of complex cognitive functions rely upon several brain regions working in tandem with each other e.g. processing speech.

There's also evidence from studies that look at what happens when the brain is damaged. Even a small injury can have major consequences and can affect a variety of processes and functions.

So whilst you don't use your entire brain all of the time (that would be extremely inefficient and tiring), you do use 100% of your brain across a relatively short time period. And though whilst this idea is false, it does hint at the idea that we haven't fully developed our brain's potential (though psychic or superhuman abilities are beyond our abilities to develop, no matter how cool they would be).

Sources:
http://lifehacker.com/5867049/nine-stubborn-brain-myths-that-just-wont-die-debunked-by-science
http://www.salon.com/2013/07/21/everything_you_know_about_the_brain_is_wrong/
http://www.positscience.com/brain-resources/brain-facts-myths/brain-mythology
http://science.howstuffworks.com/life/inside-the-mind/human-brain/10-brain-myths.htm#page=10
http://serendip.brynmawr.edu/bb/kinser/Structure1.html