Use your brain

    31 May 2014

    A while ago I was listening to the Today programme, as we’re all obliged to do. A neuroscientist was on it talking about how to use the findings of neuroscience to improve teaching in schools. And John Humphrys, in that aggressive-pub-drunk way he has, barked something to the effect that ‘We know how neuroscience works! You only use 10 per cent of our brains! Right-brained people are creative! Left-brained people are methodical!’

    There was a marvellous, almost imperceptible pause as the neuroscientist assimilated this information before she said: ‘Yes, those are some of the famous myths about neuroscience.’

    The brain has a hard time when it comes to magical thinking and myths. I think it’s because the fact that we are our brains makes them sexier: it’d be hard to get excited at the idea that we only used 10 per cent of our kidneys, say.

    They’re pervasive myths, though, as Humphrys — an educated and presumably not stupid man — demonstrates. In the case of the ‘We only use 10 per cent of our brains’ one, the appeal is presumably that we might ‘unlock’ the other 90 per cent, and become in some way superhuman. Uri Geller makes this claim in one of his bend-spoons-and-read-minds books: ‘Most of us only use about 10 per cent of our brains… The other 90 per cent is full of untapped potential and undiscovered abilities.’

    The trouble is, it’s not only a myth, it’s a stupid one. Brain imaging has repeatedly shown that we use our entire brain, if not always at the same time; and if 90 per cent of our brain was useless, then, presumably, most brain injuries would do us no harm. In fact, there is pretty much no part of the brain you can damage or remove without affecting cognitive abilities.

    When you think about it, it would be ridiculous if it were otherwise. The brain is, pound for pound, by far the most energy-demanding organ in our bodies — it can require as much as 20 per cent of the total energy intake, despite making up just 2 per cent of our weight. Imagine two creatures: one of which dedicates hundreds of calories a day to running an entirely unused 90 per cent of its brain; and another, which makes do with the 10 per cent it uses and dedicates the spare calories to growing muscle tissue, or searching for food — or simply spends less time gathering calories, and more time seeking a mate. Which is likely to leave more offspring? If our brains weren’t being used, they’d waste away.

    The idea that we’re ‘left-brained’ or ‘right-brained’ is, on the face of it, less idiotic. We know that the two halves of our brain can act independently — people with their corpus callosum (the great nerve-bridge between the two hemispheres) severed can lead relatively normal lives. And we know that the two halves are different; the left hemisphere seems to have more to do with language processing, for instance, and attention happens mainly on the right. From that beginning, a complex mythology has built up. Questionnaires abound online, determining — by such things as which leg you cross over the other one, or which way you see an ambiguous 3D image — whether you are left- or right-brained.

    But the idea that artistic, creative people use their right hemispheres more than their left ones, and scientifically or mathematically minded people the other way around, is false. Last year a two-year study by neuroscientists at the University of Utah was published in the journal PLOS One. The authors scanned the brains of 1,011 people, and found no evidence that one side was dominant in any of them. Local networks could be more active on one side or the other, but in general the two hemispheres shared the load equally. There has never been any serious indication, in any previous study, that left hemispheres equal nerdy engineers and right hemispheres equal blouse-wearing beat poets in east London warehouse conversions.

    We love simple explanations for complex phenomena. The idea that left-brained people are methodical and right-brained people are creative is intuitive, far more so than ‘an impossibly complicated combination of genetics and upbringing creates the even more complicated thicket of connections in our brains that make us who we are’. It’s all nonsense, though: comforting, appealing, easy to believe nonsense, but nonsense nonetheless, and nonsense that could be pernicious if anyone takes it seriously, and assigns ‘left-brained’ schoolchildren to maths class and ‘right-brained’ ones to arts. Hopefully, next time a neuroscientist appears on Today, John Humphrys will have learnt his lesson.