Psychology pet-hate #54

A while ago, I wrote about an annoying question many people ask when they find out you’ve studied psychology: namely, ‘So, are you analysing me right now?’. I’m still hearing it now from colleagues at work when I divulge what I spent the last four years doing. But, don’t be fooled into thinking that’s the only bit of misinformation circling about the field of psychology!

How’s about this one: ‘But, we only use percent of our brains!’

This is a common myth which gets bandied about as a general reason for things such as not knowing how memory works, savants, and just about any other facet of the human mind that you can think of. It’s even been thrown at me at church as evidence that humans did once live for up to nine hundred years at a stretch in early Old Testament times (the rationale being that, seeing as we only use about ten percent of our brains, the other ninety percent could have been excess storage for all those extra memories we’d have).

Sorry to burst the bubble, but it’s just not true. Or, as they would say on Mythbusters, this one is busted.

I guess my first question is, how do people know that we are underutilising our brains? We certainly don’t understand the brain in its entirety, but we know a lot more than we used to, and there are now all sorts of scans and techniques for observing the brain in real-time, or close-to-real-time. One thing we do know is that the brain is not made of a homogeneous mass; that is, it isn’t just a big cottony ball of worm-like cerebral cortex. The brain is made up of structures and sections. We have a brain stem, which seems to regulate autonomous functions like breathing and heart beat; we have a visual cortex, interpreting signals from our ocular nerves; we have structures like the hippocampus, which are associated with memory; we have a pre-frontal cortex, which is thought to be the centre of planning, reasoning, and impulse control. The list goes on and on and on. Moreover, these fancy new scanning techniques show all the parts of the brain being used at different times – that’s one way we have of inferring that certain cerebral structures are designed to process different signals.

As such, if we only used ten percent of our brains, then it seems reasonable to ask which ten percent we are using. Is it the ten percent which allows us to, say, comprehend and produce written and spoken language? Or the ten percent which interprets signals from the auditory neuronal pathways? If we only use ten percent, why do patients with brain lesions experience such a variety of impairments? After all, it would be highly unlikely to cause a problem with our everyday function if the ninety percent-part was damaged. People who seem to believe this ‘fact’ cannot really answer these questions, and even if they can, their answers contradict a long history of scientific evidence which strongly suggests that any sort of brain injury has some kind of detrimental effect on human function.

This is not to say that the brain is incapable of plasticity. Stroke patients, for example, often recover some of their lost functions, and it seems that other parts of the brain take over for the part which was damaged. My grandmother-in-law has demonstrated this in her ability to form relatively-complex sentences after having a stroke several years ago, immediately after which she could only repeat her doctor’s surname. The brain has an amazing capacity to compensate for neurological problems, so maybe we should marvel at this, instead of going goggle-eyed about our supposedly-underused noggins.

Someone once said to me, ‘but, it’s not like we’re only using ten percent of the physical mass – we’re only using ten percent of our brain’s potential’. I don’t really understand what that means. I’ve heard references to the other ninety percent being to do with the subconscious or unconscious, but there’s no evidence, and no way of quantifying or demonstrating this, so I’m happy to stick with what we know. Ultimately, the ten-percent myth is the result of not understanding the brain, and so is akin to the following exchange (borrowed from snopes.com):

Two people see a strange light in the sky. The first, a UFO believer, says, “See there! Can you explain that?” The skeptic replies that no, he can’t. The UFO believer is gleeful. “Ha! You don’t know what it is, so it must be aliens!” he says, arguing from ignorance.