Modern myths of learning: You only use 10% of your brain

It’s a familiar line when casual conversation turns to the human mind: “Did you know that you only use 10% of your brain?”

The statistic is variously attributed to Albert Einstein or – if the speaker’s feeling really showy – to early psychologist William James. Neither, of course, said anything of the sort, and for very good reason: it’s not true.

The exact number varies. I’ve heard it drop through 5% to 0.1% and rise as high as 11%, a nice non-round number designed to lend the ‘fact’ gravitas. In reality, though, this non-attributable number which varies according to the aims of the speaker is something too common in the world of training: another learning myth.

Like other learning myths, this one takes a common experience and tries to give it a gloss of scientific validity by slapping a statistic on it. Some people feel the myth ‘You only remember 10% of what you read’, adds weight to the general experience of learning better from practical engagement than from reading. The ‘You only use 10% of your brain’ myth references a common feeling that we fall short of our intellectual potential.

Is there any truth in this myth? Not a jot.

Let’s be clear. A fact like this would require a lot of scientific research to substantiate, and such research is not something you can just make up. It is painstaking and usually very specific. And there is no research, no papers, and no investigation that comes close to confirming that ‘you only use 10% of the brain’.

Dr Eric Chundler of the University of Washington has done some work (also see here) exposing this myth. According to him, one possible origin is an experiment done by Karl Spencer Lashley in 1935. According to Dr Chundler: “Lashley found that removal of up to 58% of the cerebral cortex did not affect certain types of learning. It is possible that over interpretation and exaggeration of these data led to the belief that only a small portion of the brain is used.”

Dr Chundler is not the only academic who rails at the myth. US psychologist Dr Barry Beyerstein wrote extensively on the matter. And in the UK we have Dr Itiel Dror, senior lecturer in cognitive neuroscience at Southampton University. “Not only is there no scientific basis for this claim,” says Dr Dror, “it is actually scientifically incorrect. We know this through a variety of functional brain scanning methodologies. People should take the time to understand the science so they can use it to guide and drive their work, rather than make up (or repeat) fictitious and fairy tale ‘facts’ about the brain.”

A little thought reveals the absurdity of the myth. If it were true that 90% of the brain were unused, then most head injuries would not be fatal. Clearly that isn’t so. According to Raichle and Gusnard, The brain takes up 2% of the body’s weight and yet demands 20% of its energy – why waste 90% of that energy?

Could it be that only 10% of the brain is in use at any one time? The evidence suggests otherwise. Raichle and Gusnard’s appraisal of the demands of the brain’s energy looks at data from a variety of scans and imaging devices. They note that the brain is almost constantly at work: “This high metabolic activity is present when we are completely passive and resting as well as when we are observably doing something.” And this is not because the brain needs plenty of energy just to keep it ticking over. They quote research saying that “maintenance of the resting potential… accounts for less that 15% of the total energy consumption”.

And just to reinforce the point, here is an image from another paper by the same authors:

Clearly, the brain is pretty busy, even in a conscious resting state.

Could it be then, that we only use 10% of our conscious mind? Maybe, but the burden of proof for this claim rests with the person proposing it. They would be doing great work if they could just identify where the consciousness sits in the brain. If they could then isolate its activity from all other brain activity, measure it and show it to be 90% underutilized they should get out of the pub (where they’re probably making this claim) and over to Stockholm to collect their Nobel prize.

The truth is that our complex, power-hungry, magnificent brains are busy most of the time. The myth simply reflects a natural human desire to fulfil our intellectual potential. That is admirable. Making numbers up as if they will somehow give that desire more substance is not.
So who is perpetuating this myth? Although it is common enough to find it in the world of L&D, its use is particularly rampant in advertising, and, according to C. Wanjek, first appeared in writing in a 1940s advert for Cold Comfort Farm by Stella Gibbons.

But when the advertising is for self help products the myth really proliferates. For example, Mind Secrets Exposed claims: “The human brain is a very powerful tool. However, it has been estimated (by Einstein) that you only use about 5% of your minds consciously.” Their product: a $67 book – CD – software self-help package. There are many more, similar uses of this myth out there.

These products may really work, and not everyone making this claim may realise it is false. But shouldn’t they know it’s false, when a moment’s thought can show that it is? And this leads us to a question: how do we want the L&D profession to be seen?

You are known by the company you keep, and if we mindlessly repeat something that a moment’s reflection can show to be rubbish, then we are no better than any charlatan who deliberately repeats these myths only to make money by offering the lure of a mythical extra 90% brain power.

The real work in helping people get more from their intellectual potential is already being done.

It is done by the hard-working mentors, coaches, managers, colleagues and learning and development professionals who daily help people develop themselves. We know it isn’t always quick or easy, although it can – when done well – be fun, fulfilling and effective. And it doesn’t need some marketing hokum to promote it.

Real learning and development professionals don’t need to repeat this nonsense. Hard facts and good practice are enough for them.