The myth that people only use 10% of their brains has spread like wildfire. It is mainly used by ad's and psychics to get your attention.
This myth states that we really only use 10% of our brains and the rest just sits there, doing nothing. This can easily be refuted by using extraordinary claims. Using brain imaging techniques like PET scans and fMRI, people are able to see that the whole brain, in fact, is still functioning and sending neurons across the brain. Using these brain scanners, you can create an alternate explanation to this myth. The principle of replicability was ignored and that is why this was taken as fact.