Exploring the urban legend
When I was a lowly graduate student—doing my PhD thesis on the brains of boas and pythons—I had the great fortune of having dinner with two Nobel prize winning brain scientists, David Hubel and Torsten Wiesel.
Not wanting to waste the opportunity, I asked the great men: where did the idea that we only use 10% of our brains come from, and is it true?
They smiled, shook their heads, and said that they weren’t sure where the idea originated. But both agreed that the 10% theory was a myth. Nature, they observed, does not waste resources that way because there is a name for species that are inefficient: fossils.
Our brains consume about 20% of the energy our bodies use, and to invest that much energy in a function that is only 10% efficient makes no evolutionary sense. If the 10% theory were true, we would either have much smaller brains or would be extinct.