Question: Is it true that humans only have use of around 20% of their brain? If we did unlock the rest of our brains full capacity would it be like the film Lucy in which we develop many new skills and the ability to control things like technological devices?

Martha Havenith answered on 23 Jun 2015:

Hi 541, no, this is not true. What is true is that only a small portion of all neurons are active at any moment. But that would be like saying ‘We only use 50% of our limbs when we are walking. How fast would we be if we used our hands too?’ Or ‘How awesome would this song sound if all instruments played loudly at the same time?’ Different neurons are active for different tasks, so the fact that they are not all active at the same time is actually incredibly important to let the brain do its job.
I do believe though that most people don’t reach the potential of how smart and talented they can really be. There are many reasons for this. One reason is that the brain is changeable – connections between neurons only get stronger when you use them. That means that even if you have an awesome talent for something, your brain will only ‘hardwire’ that talent if you practise it. Another reason is that factors like stress, fear and even just a bad diet lower the brain’s ability to learn new things.
One final bit – even if we got super-smart somehow, our brain wouldn’t be able to control devices outside our body. It’s simply not equipped to transmit signals outside our body.