The Hour Between Dog and Wolf: Risk-taking, Gut Feelings and the Biology of Boom and Bust. John Coates

Чтение книги онлайн.

СКАЧАТЬ exhaustion. On the African savannah we did not need to outrun or outfight our prey, so this theory claims, merely outcool it.

      Many of the advances leading to our dominance over other animals did indeed take place in the body, which over time became taller, straighter, faster, cooler, more dextrous and much more talkative. Other advances of equal importance occurred in the brain. According to some evolutionary accounts, human prehistory was driven by the growth of our neo-cortex, the rational, conscious, newest and outermost layer of the brain. As this brain structure blossomed, we developed the ability to think ahead and choose our actions, and in so doing became liberated from automatic behaviours and an animal enslavement to immediate bodily needs. This story of the brain’s evolution and the increasingly abstract nature of human thinking is for the most part correct. But it is also the subplot of the evolutionary story that is most prone to misunderstanding. It can too easily imply that our bodies became ever less important to our success as a species. An extreme example of this view can be found in science fiction, where future humans are frequently portrayed as all head, a bulbous cranium sitting atop an atrophied body. Bodies, in sci-fi and to a certain extent in the popular imagination, are seen as relics of a bestial prehistory best forgotten.

      The very existence of such a story, lurking in the popular imagination, is yet another testament to the staying power of the ancient notion of a mind–body split, according to which our bodies play a secondary and largely mischievous role in our lives, tempting us from the path of reason. Needless to say, such a story is simplistic. Body and brain evolved together, not separately. Some scientists have recently begun to study the ways in which the lines of communication between body and brain became more elaborate in humans compared to other animals, how over time the brain became more tightly bound to the body, not less. With the benefit of their research we can discern another story about our history that is at once more complete and far more intriguing – that the true miracle of human evolution was the development of advanced control systems for synchronising body and brain.

      In modern humans the body and brain exchange a torrent of information. And the exchange takes place between equals. We tend to think it does not, that information from the body constitutes nothing more than mere data being input into the computer in our head, the brain then sending back orders on what to do. The brain as puppet master, the body as puppet, to change analogies. But this picture is all wrong. The information sent by the body registers as a lot more than mere data; it comes freighted with suggestions, sometimes merely whispered, at others forcefully shouted, on how your brain should use it. You experience the more insistent of these informational prods as desires and emotions, the more subtle and dimly discernible as gut feelings. Over the long years of our evolutionary prehistory, this bodily input to our thinking has proved essential for fast actions and good judgement. Indeed, if we take a closer look at the dialogue between body and brain we will come to appreciate just how crucially the body contributes to our decision-making, and especially to our risk-taking, even in the financial markets.

      WHY ANIMALS CAN’T PLAY SPORTS

      To free ourselves from the philosophical baggage that has impeded our understanding of body and brain, we should begin by asking a very basic question, perhaps the most basic in all the neurosciences: why do we have a brain? Why do some living creatures, like animals, have a brain, while others, like plants, do not?

      Daniel Wolpert, an engineer and neuroscientist at the University of Cambridge, provides an intriguing answer to this question when he tells the tale of a distant cousin of humans, a sea squirt called the tunicate. The tunicate is born with a small brain, called a cerebral ganglion, complete with an eyespot for sensing light, and an otolith, a primitive organ which senses gravity and permits the tunicate to orient itself horizontally or vertically. In its larval stage the tunicate swims freely about the sea searching for rich feeding grounds. When it finds a promising spot it cements itself, head-first, to the sea floor. It then proceeds to ingest its brain, using the nutrients to build its siphons and tunic-like body. Swaying gently in the ocean currents, filtering nutrients from passing water, the tunicate lives out its days without the need or burden of a brain.

      Fig. 2. The bluebell tunicate.

      To Wolpert, and many like-minded scientists, the tunicate is sending us an important message from our evolutionary past, telling us that if you do not need to move, you do not need a brain. The tunicate, they say, informs us that the brain is fundamentally very practical, that its main role is not to engage in pure thought but to plan and execute physical movement. What is the point, they ask, of our sensations, our memories, our cognitive abilities, if these do not lead at some point to action, be it walking, or reaching, or swimming, or eating, or even writing? If we humans did not need to move then perhaps we too would prefer to ingest our brain, a metabolically expensive organ, consuming some 20 per cent of our daily energy. Scientists who believe the brain evolved primarily to control movement – Wolpert calls himself and his colleagues ‘motor chauvinists’ – argue that thought itself is best understood as planning; even higher forms of thought, such as philosophy, the epitome of disembodied speculation, proceed, they argue, by hijacking algorithms originally developed to help us plan movements. Our mental life, they argue, is inescapably embodied. Andy Clark, a philosopher from Edinburgh, has put this point nicely when he states that we have inherited ‘a mind on the hoof’.

      To understand the brain, therefore, we need to understand movement. Yet that has turned out to be a lot harder than anyone imagined, harder in a sense than understanding the products of the intellect. We tend to believe that what belongs in the pantheon of human achievement are the books we have written, the theorems we have proved, the scientific discoveries we have made, and that our highest calling involves a turning away from the flesh, with its decay and temptation, and towards a life of the mind. But such an attitude often blinds us to the extraordinary beauty of human movement, and to its baffling mystery.

      Such is the conclusion drawn by many engineers who have tried to model human movement or to replicate it with a robot. They have quickly come to a sobering realisation – that even the simplest of human movements involves a mind-boggling complexity. Steven Pinker, for example, points out that the human mind is capable of understanding quantum physics, decoding the genome and sending a rocket to the moon; but these accomplishments have turned out to be relatively simple compared to the task of reverse-engineering human movement. Take walking. A six-legged insect, even a four-legged animal, can always keep a tripod of three legs on the ground to balance itself while walking. But how does a two-legged creature like a human do it? We must support our weight, propel ourselves forward, and maintain our centre of gravity, all on the ball of a single foot. When we walk, Pinker explains, ‘we repeatedly tip over and break our fall in the nick of time’. The seemingly simple act of taking a step is in truth a technical tour de force, and, he reports, ‘no one has yet figured out how we do it’. If we want to observe the true genius of the human nervous system, we should therefore look not so much to the works of Shakespeare or Mozart or Einstein, but to a child building a Lego castle, or a jogger running over an uneven surface, for their movements entail solving technical problems which for the moment lie beyond the ken of human understanding.

      Wolpert has come to a similar conclusion. He points out that we have been able to program a computer to beat a chess grandmaster because the task is merely a large computational problem – work out all possible moves to the end of the game and choose the best one – and can be solved by throwing a lot of computing power at it. But we have not yet been able to build a robot with the speed and manual dexterity of an eight-year-old child.

      Our physical abilities are awe-inspiring, and they remain so even when compared to those of the animals. We tend to think that as we evolved out of our bodies and into our larger brains we left physical prowess behind, with the brutes. We may have a larger prefrontal cortex relative to brain size than any animal, but animals outclass us in pretty well any measure of physical performance. We are not as large as an elephant, not as strong as a gorilla, nor as fast as a cheetah. Our СКАЧАТЬ