The Idiot Brain Read online

  The Idiot Brain

  A Neuroscientist Explains What

  Your Head is Really Up To

  DEAN BURNETT

  Dedicated to every human with a brain.

  It’s not an easy thing to put up with, so well done.

  Contents

  Title Page

  Dedication

  Introduction

  1 Mind controls How the brain regulates the body, and usually makes a mess of things

  2 The gift of memory (keep the receipt) The human memory system, and its strange features

  3 Fear: nothing to be scared of The many ways in which the brain makes us constantly afraid

  4 Think you’re clever, do you? The baffling science of intelligence

  5 Did you see this chapter coming? The haphazard properties of the brain’s observational systems

  6 Personality: a testing concept The complex and confusing properties of personality

  7 Group hug! How the brain is influenced by other people

  8 When the brain breaks down … Mental health problems, and how they come about

  Afterword

  Acknowledgements

  Index

  About the Author

  Copyright

  Introduction

  This book begins the same way as nearly all my social interactions; with a series of detailed and thorough apologies.

  Firstly, if you end up reading this book and not liking it, I’m sorry. It’s impossible to produce something that will be liked by everyone. If I could do that, I’d be the democratically elected leader of the world by now. Or Dolly Parton.

  To me, the subjects covered in this book, focusing on the weird and peculiar processes in the brain and the illogical behaviours they produce, are endlessly fascinating. For example, did you know that your memory is egotistical? You might think it’s an accurate record of things that have happened to you or stuff you’ve learned, but it isn’t. Your memory often tweaks and adjusts the information it stores to make you look better, like a doting mother pointing out how wonderful her little Timmy was in the school play, even though little Timmy just stood there, picking his nose and dribbling.

  Or how about the fact that stress can actually increase your performance at a task? It’s a neurological process, not just ‘something people say’. Deadlines are one of the most common ways of inducing stress that provoke an increase in performance. If the latter chapters of this book suddenly improve in quality, you now know why.

  Secondly, while this is technically a science book, if you were expecting a sober discussion of the brain and its workings, then I apologise. You won’t be getting that. I am not from a ‘traditional’ scientific background; I’m the first out of everyone in my family to so much as think about going to university, let alone go, stay there and end up with a doctorate. It was these strange academic inclinations, so at odds with my closest relatives, that first got me into neuroscience and psychology, as I wondered, ‘Why am I like this?’ I never really found a satisfying answer, but I did develop a strong interest in the brain and its workings, as well as in science in general.

  Science is the work of humans. By and large, humans are messy, chaotic and illogical creatures (due largely to the workings of the human brain) and much of science reflects this. Someone decided long ago that science writing should always be lofty and serious, and this notion seems to have stuck. Most of my professional life has been dedicated to challenging it, and this book is the latest expression of that.

  Thirdly, I’d like to say sorry to any readers who find themselves referencing this book and subsequently losing an argument with a neuroscientist. In the world of brain sciences, our understanding changes all the time. For every claim or statement made in this book, you’d probably be able to find some new study or investigation that argues against it. But, for the benefit of any newcomers to science reading, this is pretty much always the case with any area of modern science.

  Fourthly, if you feel the brain is a mysterious and ineffable object, some borderline-mystical construct, the bridge between the human experience and the realm of the unknown, etc., then I’m sorry; you’re really not going to like this book.

  Don’t get me wrong, there really is nothing as baffling as the human brain; it is incredibly interesting. But there’s also this bizarre impression that the brain is ‘special’, exempt from criticism, privileged in some way, and our understanding of it is so limited that we’ve barely scratched the surface of what it’s capable of. With all due respect, this is nonsense.

  The brain is still an internal organ in the human body, and as such is a tangled mess of habits, traits, outdated processes and inefficient systems. In many ways, the brain is a victim of its own success; it’s evolved over millions of years to reach this current level of complexity, but as a result it has accrued a great deal of junk, like a hard drive riddled with old software programs and obsolete downloads that interrupt basic processes, like those cursed pop-ups offering you discount cosmetics from long-defunct websites when all you’re trying to do is read an email.

  Bottom line: the brain is fallible. It may be the seat of consciousness and the engine of all human experience, but it’s also incredibly messy and disorganised despite these profound roles. You have only to look at the thing to grasp how ridiculous it is: it resembles a mutant walnut, a Lovecraftian blancmange, a decrepit boxing glove, and so on. It’s undeniably impressive, but it’s far from perfect, and these imperfections influence everything humans say, do and experience.

  So rather than the brain’s more haphazard properties being downplayed or just flat out ignored, they should be emphasised, celebrated even. This book covers the many things the brain does that are downright laughable and how they affect us. It also looks at some of the ways people have thought the brain works that have proved to be way off. Readers of this book should, I hope, come away with a better and reassuring understanding of why people (or they themselves) regularly do and say such weird things, as well as with the ability to legitimately raise a sceptical eyebrow when confronted with the increasing amount of brain-based neuro-nonsense in the modern world. If this book can claim to have anything as lofty as overarching themes or aims, these are they.

  And my final apology is based on the fact that a former colleague of mine once told me that I’d get a book published ‘when hell freezes over’. Sorry to Satan. This must be very inconvenient for you.

  Dean Burnett, PhD (no, really)

  1

  Mind controls

  How the brain regulates the body, and usually makes a mess of things

  The mechanics that allow us to think and reason and contemplate didn’t exist millions of years ago. The first fish to crawl onto land aeons ago wasn’t racked with self-doubt, thinking, ‘Why am I doing this? I can’t breathe up here and I don’t even have any legs, whatever they are. This is the last time I play truth-or-dare with Gary.’ No; until relatively recently, the brain had a much more clear and simple purpose: keeping the body alive by any means necessary.

  The primitive human brain was obviously successful because we as a species endured and are now the dominant life-form on earth. But despite our evolved complicated cognitive abilities, the original primitive brain functions didn’t go away. If anything, they became more important; having language and reasoning skills doesn’t really amount to much if you keep dying from simple things like forgetting to eat or wandering off cliffs.

  The brain needs the body to sustain it, and the body needs the brain to control it and make it do necessary things. (They’re actually far more intertwined than this description suggests, but just go with it for now.) As a result, much of the brain is dedicated to basic physiological processes, monitoring internal workings, coordinating responses to
problems, cleaning up mess. Maintenance, essentially. The regions that control these fundamental aspects, the brainstem and cerebellum, are sometimes referred to as the ‘reptile’ brain, emphasising their primitive nature, because it’s the same thing the brain was doing when we were reptiles, back in the mists of time. (Mammals were a later addition to the whole ‘life-on-earth’ scene.) By contrast, all the more advanced abilities we modern humans enjoy – consciousness, attention, perception, reasoning – are found in the neocortex, ‘neo’ meaning ‘new’. The actual arrangement is far more complex than these labels suggest, but it’s a useful shorthand.

  So you might hope that these parts – the reptile brain and the neocortex – would work together harmoniously, or at least ignore each other. Some hope. If you’ve ever worked for someone who’s a micromanager, you know how incredibly inefficient this arrangement can be. Having someone less experienced (but technically higher ranking) hovering over you, issuing ill-informed orders and asking dumb questions can only ever make it harder. The neocortex does this with the reptile brain all the time.

  It’s not all one way though. The neocortex is flexible and responsive; the reptile brain is set in its ways. We’ve all met people who think they know best because they’re older or have been doing something for longer. Working with these people can be a nightmare, like trying to write computer programs with someone who insists on using a typewriter because ‘that’s how it’s always been done’. The reptile brain can be like that, derailing useful things by being incredibly obstinate. This chapter looks at how the brain messes up the more basic functions of the body.

  Stop the book, I want to get off!

  (How the brain causes motion sickness)

  Modern humans spend a lot more time sitting down than ever before. Manual-labour jobs have largely been replaced by office jobs. Cars and other means of transport mean we can travel while sitting down. The Internet means it is possible to spend practically your whole life sitting down, what with telecommuting, online banking and shopping.

  This has its down sides. Obscene sums are spent on ergonomically designed office chairs to make sure people don’t get damaged or injured due to excessive sitting. Sitting too long on an aeroplane can even be fatal, due to deep vein thrombosis. It seems odd, but very little movement is damaging.

  Because moving is important. Humans are good at it and we do it a lot, as evidenced by the fact that, as a species, we’ve pretty much covered the surface of the earth, and actually been to the moon. Walking two miles a day has been reported as being good for the brain, but then it’s probably good for every part of the body.1 Our skeletons have evolved to allow long periods of walking, as the arrangement and properties of our feet, legs, hips and general body layout are ideally suited to regular ambulation. But it’s not just the structure of our bodies; we’re seemingly ‘programmed’ to walk without even getting the brain involved.

  There are nerve clusters in our spines that help control our locomotion without any conscious involvement.2 These bundles of nerves are called pattern generators, and are found in the lower parts of the spinal cord in the central nervous system. These pattern generators stimulate the muscles and tendons of the legs to move in specific patterns (hence the name) to produce walking. They also receive feedback from the muscles, tendons, skin and joints – such as detecting if we’re walking down a slope – so we can tweak and adjust the manner of movement to match the situation. This may explain why an unconscious person can still wander about, as we’ll see in the phenomenon of sleepwalking later in this chapter.

  This ability to move around easily and without thinking about it – whether fleeing dangerous environments, finding food sources, pursuing prey or outrunning predators – ensured our species’s survival. The first organisms to leave the sea and colonise the land led to all air-breathing life on earth; they wouldn’t have done so if they’d stayed put.

  But here’s the question: if moving is integral to our well-being and survival, and we’ve actually evolved sophisticated biological systems to ensure it happens as often and as easily as possible, why does it sometimes make us throw up? This is the phenomenon known as motion sickness or travel sickness. Sometimes, often apropos of nothing, being in transit makes us bring up our breakfast, lose our lunch, or eject some other more recent but non-alliterative meal.

  It’s the brain that’s actually responsible for this, not the stomach or innards (despite how it may feel at the time). What possible reason could there be for our brains to conclude, in defiance of aeons of evolution, that going from A to B is a legitimate cause for vomiting? In actual fact, the brain isn’t defying our evolved tendencies at all. It’s the numerous systems and mechanisms we have to facilitate motion that are causing the problem. Motion sickness occurs only when you’re travelling by artificial means –when you’re in a vehicle. Here’s why.

  Humans have a sophisticated array of senses and neurological mechanisms that give rise to proprioception, the ability to sense how our body is currently arranged, and which parts are going where. Put your hand behind your back and you can still sense the hand, know where it is and what rude gesture it’s making, without actually seeing it. That’s proprioception.

  There’s also the vestibular system, found in our inner ear. It’s a bunch of fluid-filled canals (meaning ‘bony tubes’ in this context) to detect our balance and position. There’s enough space in there for fluid to move about in response to gravity, and there are neurons throughout it that can detect the location and arrangement of the fluids, letting our brain know our current position and orientation. If the fluid is at the top of the tubes, this means we’re upside-down, which probably isn’t ideal and should be remedied as soon as possible.

  Human motion (walking, running, even crawling or hopping) produces a very specific set of signals. There’s the steady up–down rocking motion inherent in bipedal walking, the general velocity and the external forces such as the movement of air passing you and your shifting internal fluids that this produces. All of these are detected by proprioception and the vestibular system.

  The image hitting our eyes is one of the outside world going by. The same image could be caused either by us moving or by us staying still and the outside world going past. At the most basic level, both are valid interpretations. How does the brain know which is right? It receives the visual information, couples it with the information from the fluid system in the ear and concludes ‘body is moving; this is normal’, and then goes back to thinking about sex or revenge or Pokemon, whatever it is you’re into. Our eyes and inner systems work together to explain what’s going on.

  Movement via a vehicle produces a different set of sensations. Cars don’t have that signature rhythmical rocking motion that our brains associate with walking (unless your suspension is well and truly shot), and the same usually goes for planes, trains and ships. When you’re being transported, you’re not the one actually ‘doing’ the moving; you’re just sitting there doing something to pass the time, such as trying to stop yourself from throwing up. Your proprioception isn’t producing all those clever signals for the brain to comprehend what’s going on. No signals means you’re not doing anything to the reptile brain, and this is reinforced by your eyes telling it you’re not moving. But you are actually moving, and the aforementioned fluids in your ear, responding to the forces caused by high-speed movement and acceleration, are sending signals to the brain that are saying you are travelling, and quite fast at that.

  What’s happening now is that the brain is getting mixed signals from a precisely calibrated motion-detection system, and it is believed that this is what causes motion sickness. Our conscious brain can handle this conflicting information quite easily, but the deeper, more fundamental subconscious systems that regulate our bodies don’t really know how to deal with internal problems like this, and they’ve no idea what could possibly be happening to cause the malfunction. In fact, as far as the reptile brain is concerned, there’s only one likely answer: poiso
n. In nature, that’s the only likely thing that can so deeply affect our inner workings and cause them to get so confused.

  Poison is bad, and if the brain thinks there’s poison in the body, there’s only one reasonable response: get rid of it, activate the vomiting reflex, pronto. The more advanced brain regions may know better, but it takes a lot of effort to alter the actions of the fundamental regions once they’re under way. They are ‘set in their ways’ after all, almost by definition.

  The phenomenon is still not totally understood at present. Why don’t we get motion sickness all the time? Why do some people never suffer from it? There may well be many external or personal factors, such as the exact nature of the vehicle in which you are travelling, or some neurological predisposition to sensitivity to certain forms of movement, that contribute to occurrence of motion sickness, but this section sums up the most popular current theory. An alternative explanation is the ‘nystagmus hypothesis’,3 which argues that the inadvertent stretching of the extra-ocular muscles (the ones that hold and move the eyes) due to motion stimulates the vagus nerve (one of the main nerves that control the face and head) in weird ways, leading to motion sickness. In either case, we get motion sickness because our brain gets easily confused and has a limited number of options when it comes to fixing potential problems, like a manager who’s been promoted above his or her ability level and responds with buzzwords and crying fits when asked to do anything.

  Seasickness seems to hit people the hardest. On land there are many items in the landscape to look at that reveal your movements (for instance, trees going past); on a ship there’s usually just the sea and things that are too far away to be of any use, so the visual system is even more likely to assert that there’s no movement happening. Travelling on the sea also adds an unpredictable up–down motion that gets the ear fluids firing off even more signals to an increasingly confused brain. In Spike Milligan’s war memoir Adolf Hitler: My Part in His Downfall, Spike was transferred to Africa by ship during World War II, and was one of the only soldiers in his squad who didn’t succumb to seasickness. When asked what the best way to deal with seasickness was, his reply was simply, ‘Sit under a tree.’ There’s no supporting research available, but I’m fairly confident this method would work to prevent airsickness too.