Top motivational myths, and why we don’t need them. Number three. Spare brain capacity

We only use 10% of our brain. Or do we?

This myth is very attractive; it suggests that there’s a huge hidden part of the human brain just waiting to be unlocked.  It’s a popular science fiction theme in films and books.  In the film ‘Lucy’, Scarlett Johansson plays a  character who is implanted with drugs that allow her to access 100 percent of her brain capacity.  She is able to learn Chinese in an instant, beat up bad guys, and throw cars with her mind (among other new talents).  Morgan Freeman plays neuroscientist Professor Norman, who’s built his career around the 10 percent claim. “It is estimated most human beings use only 10 percent of the brain’s capacity,” he says, “Imagine if we could access 100 percent.”

Of course it’s just not true – we humans use all of our brain at different times.  Brain scans show this very clearly, and they track activity across the whole of the brain.  “Evidence would show over a day you use 100 percent of the brain,” says John Henley, a neurologist at the Mayo Clinic in Rochester, Minn.  The brain is only about 3% of our body mass but it uses 20% of our calorie intake – wow, maybe thinking can make me slim!  No organism can afford to give that much to one organ and then only use a tiny part of it.

So where does this idea come from? Various explanations have been put forward, but the most likely one is a simple misunderstanding of early work on how the brain functions.  Only about 10% of brain cells are neurons (the ones that light up on all the scans and transmit information in the brain), the others have different functions. This may be at the bottom of it.  Either way, it’s another myth that you hear quoted all the time.

But what people often mean when they talk about this ‘unused’ part of the brain, is actually the subconscious.  The part of our mind which is outside our control, where our attitudes, moods and habits are found. Accessing that is a whole different ball game, watch this space …..

Ultimately, it’s not that we use 10 percent of our brains, merely that we only understand about 10 percent of how it functions.

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