Explaining the "we only use 10% of our brains" myth

"We only use 10% of our brains" - it's a piece of 'knowledge' that has seeped into everything from school science lessons to first aid classes, according to Jordan Gaines Lewis, writing for the Conversation.

But it's not supported by the science. As she explains, most people use most of their brain every day.

So where did the figure come from?

We can't be sure, but the article raises a couple of possibilities.

Its initial spread in the early 20th century might be down to a misunderstanding of the findings of a psychologist. William James thought people underused their mental resources, but it was others who ascribed to him the specific figure of 10%.

And it might've been reinforced by findings that neurons are a minority of brain cells. The fact they are outnumbered roughly 10:1 by 'glial' cells - the exact ratio is under dispute - might suggest to a layperson that we're only 'using' a minority of our brains.

But as Gaines Lewis says, glial cells are amongst other things, "responsible for maintaining homeostasis (keeping everything ticking well)"

So these cells are being 'used' - without them we might lose organ function, for example.