BY PROF DEAN BURNETT
Contrary to popular misconception (and there’s the rub) our brain is not this other-world “being” living in our skulls, beyond our comprehension with its workings to be revered on a quasi-religious basis. It’s a blood and tissue organ like all our others, working to the same physical stimuli and constraints.
The human brain. The most complex thing known to our civilization, the source of every great idea, inspiring artwork, breath-taking creation and world-changing discovery. True, it’s the source of all the mundane and downright bad and terrible things we’ve come up with too, but that just shows how diverse it really is. It gifts us our complex, rich perception of the world, the ability to predict, to anticipate, to empathise, to even think about times other than now, and individuals other than ourselves, something beyond most species we share our planet with.
Our brains being so powerful, so complex, so key to our very existence, it’s no wonder that they’ve gained a certain reverence, or ‘mystique’. Discussions of them in the mainstream will often portray the human brain as some enigmatic, unknowable object that we are barely beginning to understand, but we do know how amazing and powerful it is. Indeed, read some articles and claims and the brain often sounds like some unfathomable box of low-key superpowers, accessible to only the most diligent, disciplined and pure of spirit.
The problem with this portrayal is, it’s wrong. Quite clearly. And in many ways.
For one, the idea that the human brain is just one big powerful blob of mystery nestled in our skulls does a great disservice to the many intrepid neuroscientists and other researchers who have been doing their best to study it for centuries, from 16th century doctors and surgeons doing their best to treat severe head injuries from the battlefield with their terrifyingly inadequate medical knowledge, 20th century scientists like Eric Kandel, who discovered the functioning of the synapse (the ‘connection’ between neurons, nerve cells) in the 1970s. Due to the limited technology available at the time, Kandel and his colleagues were unable to insert the important electrodes into human or mammal neurons; they were just far too small to have any hope of this. They got around this by studying Aplysia, Aka the California sea slug, a metre-long aquatic gastropod with a pronounced gill and a rudimentary nervous system, but a nervous system that has some absolutely massive neurons, some of which are about a millimetre across. Doesn’t sound like much, but it I human neurons were the width of a drinking straw, aplysia would have neurons wider than a subway tunnel.
Kandel and his fellow researchers could use these to discover the function of the synapse, netting them a Nobel prize in 2000.
The point is, thanks to the combined efforts of countless researchers across the years, via techniques that go from prodding the skulls of those who’ve suffered major head trauma to the surreal marriage of hard physics, IT and biology that gives us MRI scanners, we do actually know a lot about the brain now. And what we do know shows that, far from being some ineffable ball of mysterious powers that should only talked about in hushed tones and with the appropriate reverence, the brain is, in fact, quite idiot in many ways. Obviously, it is still incredibly complex and powerful, but the idea that it’s perfect or unknowable really needs to be junked, because it’s far from that. It’s still, despite everything else, a biological organ, one that evolved with all the limitations and questionable properties of any other.
Here’s an example; we’ve all heard the claim that ‘we only use 10% of our brains’, but that’s nonsense. Among other things, because of all the complex and energetic processes it performs, the brain is undoubtedly the most demanding, ‘hungry’ organ, using up to a third of the energy stores available in the human body, just to stay alive. If we only used 10% of the brain, that would mean close to a third of our body’s energy stores are being used up for nothing. Whether you believe in evolution or intelligent design, this is a ridiculously inefficient set-up. Thankfully, it’s not the case. Every part of the brain is there for a reason, and has a role to play. We may not know what these roles are, and exactly how the various parts interact, but all of the brain is useful for something.
However, ‘using’ a particular part of the brain means increasing its activity beyond the baseline level, like pressing down on an idling car’s accelerator. This requires more energy, oxgen and metabolites, supplied by the blood. The thing is, because of the nature of the blood supply to the brain, we have a very limited ability to ‘activate’ certain parts of it. Some studies suggest that, because of the restrictions of the brain’s blood supply, we can only activate 3% of it at any one time, which may explain why we become so quickly confused and overwhelmed. It’s ironic that the 10% myth is both a ridiculous underestimate and a large overestimate of how active the brain is.
But, even if we could somehow get more blood to the brain and allow it to do more, this doesn’t mean it’ll automatically become more efficient and capable, because the way it does things is often limited, illogical, confusing, or just plain wrong. For instance, people think they know what ‘short term memory’ means. It’s memory for things that happened recently, like a half hour, or maybe a day, or a week ago. But it isn’t. Short-term memory lasts, at best, just over a minute. Anything you can remember from further back, that’s a long-term memory. It takes the brain about a minute to knit together the new synapses it uses to represent and store memories, until then they’re held in patterns of neuronal activity in the frontal lobe, which is the short-term memory. But this isn’t a stable way of storing anything, it’s like writing a memo in the foam on your coffee, hence short-term memory is so brief and limited, able to hold only four bits of information at once according to the most recent data. This is part of the reason why you can head to a different room and forget what it is you wanted once you get there; whatever it is, it’s fallen out of your short-term memory en-route.
The senses are another area where the brain is actually far less powerful than is usually assumed. We think we get this rich, diverse perception of the world around us, relayed via our sensory systems to our brains which just sits there and absorbs it, like a hard drive receiving a feed from a security camera. But that’s not how it works at all; our sensory apparatus essentially relays a constant series of neural impulses to the brain, which then has to do some serious polishing and processing to convert these into something useful. This involves a lot of guesswork and extrapolation though, hence our senses can be so easily confused, by illusions, hallucinations, distortions and so on.
And that’s nothing compared to memory, which is nowhere near as fixed and rigid as you might think. Or hope. The simple act of retrieving a memory and retelling it to others risks altering it, subtly at first, but over time you could end up remembering with crystal clarity something that never happened like that at all, because you’ve tweaked and elaborated and exaggerated over the years, but the brain’s memory systems have saved all this too, ‘updating’ the original memory, almost always unnecessarily.
If we look at the role of consciousness and our ‘higher’ intellectual abilities, it gets even more ridiculous. Our conscious mind can trigger the threat detection systems of the brain, that initiate the stressful fight or flight response, even when it’s not at all necessary. A simple creature like a shrew or a sparrow need only feel stress when they see a predator, or go too long without food, but our brains mean we get stressed at things like the possibility of a poor economy meaning we might lose our jobs. Something that hasn’t happened, that poses no physical danger to us, that may never happen, can make us stressed.
There’s so much more about the brain that defies logic. That’s why I wrote my book, ‘Idiot Brain: what your head is really up to’, to highlight all these flaws and irregularities and issues and concerns we have about the brain, because we know enough to say for certain that it isn’t perfect and awesome at all times, despite what others may suggest.
This is a good thing though. The idea that our brains are perfect and all-powerful means that when things go awry, as they often do given how messy the brain is, causing mental health issues and similar, it suggests something fundamentally wrong has occurred, and that we’re flawed in some way. That’s not true though; our brains can and do go wrong all the time, and being aware of that can be a big help in dealing with it when it does.
It may seem dispiriting or unhelpful, to find out that our brains are in fact imperfect and not all-powerful as many would claim, but I disagree. It’s far less cheering to think of us failing to live up to our potential than it is to see ourselves as overcoming our limitations. And that’s what humans do, all the time. That’s one of the best things about the human brain; it has all these flaws, but it carries on regardless.
Idiot Brain: What Your Head Is Really Up To (W.W. Norton & Company, 2016) by Dean Burnett