I was recently asked which scientific 'myth' I'd like to see banished forever from the cultural awareness. Predictably, given the decades I’ve spent in the field of neuroscience, I had to choose the persistent notion that we humans 'only use 10 per cent of our brains'.
We’ve all heard this, the notion that everything our brains do on a day-to-day basis is handled by just 10 per cent of our grey matter, and the rest is unused for some reason. It’s just sitting there, waiting to be exploited, offering so much potential.
Let’s be clear, this idea is nonsense, and always has been. And many a scientist over the years has pointed this out. But seemingly to no avail, as it keeps popping up all the time. But here’s the thing; it's not just a silly notion, something that leads to eye rolls and shoddy movie plots. It's worse than that. You could argue that it’s actually dangerous.
To begin with, the origins of the 'we only use 10 per cent of our brain' notion are unclear. Some contend that it stems from the fact that the original staining methods, essential for studying neural tissue, only stained a small percentage of neurons.
This actually made neurons visible under a microscope for the first time, as neural tissue is so densely packed. But you can see how misunderstandings could occur from this.
A similar possible origin may be that it was widely believed that neurons only made up 10 per cent of our brain cells, with the rest being glia, ‘support’ cells. More recent studies show this to be a huge oversimplification, if not just flat-out wrong. It also assumed that glia were less ‘functional’ than is the case.
As stated, the true origins of the myth remain unclear. But what we can say for certain is that they go back over a century. Perhaps even back to the 19th. So that’s well over a hundred years of neurological misinformation that’s permeated into modern culture.
It also reveals the dangers of making firm, blanket conclusions based on very old research. However accomplished, competent, and professional they were, 19th-century scientists didn't have the tools we have now.
Making concrete conclusions based on their work is sometimes like a small child only being able to lift 10 per cent of the weight of the weekly grocery shop, and everyone saying "Oh, so 90 per cent of every grocery shop is mysteriously unused".
And here’s another thing; the 10 per cent of the brain myth is wrong twice.
To confirm, 100 per cent of the brain is used, for something. We may not know what, but it's definitely there for a reason. However, 'used' means 'activated to complete a task' – the idea that we use 10 per cent of our brain is a significant overestimate.
It’s important to remember that the brain is an intensely resource-hungry, and very dense, organ, meaning there's not much room for vital blood vessels. According to some studies, this limits our ability to shunt essential resources from one part of the brain to another, to the extent that we can only activate, ‘use’ 3 per cent of our brain at once.
It’s like the brain is a busy restaurant with 100 tables, but only three waiting staff. The restaurant is all used, or useable, but a maximum of only three tables can be tended to at any one time.
So, the 10 per cent myth is wrong in two, opposing ways.
That leads to another aspect of how the 10 per cent of the brain myth is wrong; the brain is a wildly demanding organ. It makes up just 2 per cent of our body weight, but uses around 20 per cent of our body's energy, just by being alive.
As such, the brutal logic of evolution means that if we only used 10 per cent of our brains, we'd only have 10 per cent of our brain. Because having a brain as biologically demanding as ours, but only using 10 per cent of it, is like bolting a one-tonne supercomputer onto your sports car, just to keep the clock updated and play MP3s.
So, the myth is wrong in a variety of ways. And yet, it persists. And that’s worrying, because one thing it does do is provide a get-out-of-jail-free card to any hack or charlatan who makes claims that depend on ignorance, or misrepresentation, of how the brain works.
Psychics, mediums, extrasensory perception enthusiasts, faith healers, and other of that ilk etc; they make claims that cannot be true according to everything we know about science. And you can provide people with reams of evidence that prove this conclusively. But if they can say "Ah, but we only use 10 per cent of our brains, so..."
In essence, the 'we only use 10 per cent of our brain' myth provides a huge 'unknown' space for pseudoscientific/bogus brain-based claims to hide in. All established neuroscience is within the 10 per cent, so logically anything it disagrees with it must be from the 90 per cent.
And the more people who accept that myth as fact, the more fertile terrain those who depend on brain-based ignorance will have to exploit.
And that's, you know... bad? At least I think it is.
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