One of the brain regions responsible for this early-warning system is the locus ceruleus (pronounced ser-u-leus), so called because its cells are cerulean, or deep blue. Situated in the brain stem, the most primitive part of the brain, sitting atop the spine, the locus ceruleus responds to novelty and promotes a state of arousal. When a correlation between events breaks down or a new pattern emerges, when something is just not right, this primitive part of the brain registers the change long before conscious awareness. By doing so it places the brain on high alert, galvanising us into a state of heightened vigilance, and lowering our sensory thresholds so that we hear the faintest sound, notice the slightest movement. Athletes experiencing this effect have said that when caught up in the flow of a game they can pick outevery voice in the stadium, see every blade of grass.
Rising levels of testosterone increase Scott and Logan’s haemoglobin, and consequently their blood’s capacity to carry oxygen; the testosterone also increases their state of confidence and, crucially, their appetite for risk.
Adrenalin quickens physical reactions and speeds up the body’s metabolism, tapping into glucose deposits, mostly in the liver, and flushing them into the blood so that Scott and Logan have back-up fuel supplies to support them in whatever trouble their testosterone gets them into. A third hormone, the steroid cortisol, commonly known as the stress hormone, trickles out of the rim of the adrenal glands and travels to the brain, where it stimulates the release of dopamine, a chemical operating along neural circuits known as the pleasure pathways. Normally stress is a nasty experience, but not at low levels. At low levels it thrills.
Hubris Syndrome. This syndrome is characterised by recklessness, an inattention to detail, overwhelming self-confidence and contempt for others; all of which, he observes, ‘can result in disastrous leadership and cause damage on a large scale’. The syndrome, he continues, ‘is a disorder of the possession of power, particularly power which has been associated with overwhelming success, held for a period of years and with minimal constraint on the leader’.
"Animal spirits’, coined in the 1930s by Keynes when he gestured towards some ill-defined and non-rational force animating entrepreneurial and investor risk-taking
Hormones are chemical messengers carried by the blood from one tissue in the body to another
Steroid hormones - includes testosterone, oestrogen and cortisol, the main hormone of the stress response. Steroids exert particularly widespread effects because they have receptors in almost every cell in our body and brain
McEwen discovered that there are steroid receptors in brain regions other than the hypothalamus.
The steroid also returns to the brain, changing the very way we think and behave.
steroid hormone, because of its widespread receptors, can alter almost every function of our body (its growth, shape, metabolism, immune function) and of our brain (its mood and memory) and of our behaviour.
Steroid hormones evolved to coordinate body, brain and behaviour during archetypal situations, such as fighting, fleeing, feeding, hunting, mating and struggling for status. At important moments like these you need all your tissues cooperating on the task at hand; you do not
Adrenalin is a fast-acting hormone, taking effect in seconds and having a half-life in the blood of only two to three minutes, cortisol
Cortisol has one main and far-reaching command: glucose now!
Pythagoras, who needed the idea of an immortal soul for his doctrine of reincarnation, but the idea of a mind–body split was cast in its most durable form by Plato, who claimed that within our decaying flesh there flickers a spark of divinity, this being an eternal and rational soul. The idea was subsequently taken up by St Paul and enthroned as Christian dogma. It was by that very edict also enthroned as a philosophical conundrum later known as the mind–body problem; and later physicists such as René Descartes, a devout Catholic and committed scientist, wrestled with the problem of how this disembodied mind could interact with a physical body, eventually coming up with the memorable image of a ghost in the machine, watching and giving orders.
Today Platonic dualism, as the doctrine is called, is widely disputed within philosophy and mostly ignored in neuroscience.
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.
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. 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
What is truly extraordinary about humans is our ability to learn physical movements that do not in some sense come naturally, like dancing ballet, or playing the guitar, or performing gymnastics, or piloting a plane in an aerial dogfight, and to perfect them
Bud Craig, a physiologist at the University of Arizona. He has mapped out the nervous circuitry responsible for a remarkable phenomenon known as interoception, the perception of our inner world. Interoceptive information is collected by a forest of nerves that flow back from every tissue in the body to the brain, travelling along nerves that feed into the spinal cord or along a superhighway of a nerve, called the vagus nerve, that travels up from the abdomen to the brain, collecting information from the gut, pancreas, heart and lungs. All this information is then channelled through various integration sites – regions of the brain that collect disparate individual sensations and assemble them into a unified experience – ending up in a region of the cortex called the insula, where something like an image of the overall state of the body is formed.
We group objects into units of three or four in order to perceive numbers rather than count them, a process, known as subitising.
Light travels faster than sound, much faster, so visual images reach our senses before sounds. However, once the sensations reach our eyes and ears, the relative speeds of the processing circuits reverse. Hearing is faster and more acute than seeing, about 25 per cent so, and responding to an auditory cue rather than a visual one can save us up to 50 milliseconds. The reason is that sound receptors in the ear are much faster and more sensitive than anything in the eye. Many athletes, such as tennis and table-tennis players, rely on the sound a ball makes on a racket or bat as much as on the sight of its trajectory.
Researchers at the University of Pennsylvania, for example, have found that the human retina transmits to the brain approximately 10 million bits of information per second, roughly the capacity of an ethernet connection; and Manfred Zimmermann, a German physiologist, has calculated that our other senses record an additional one million bits of information per second. That gives our senses a total bandwidth of 11 million bits per second. Yet of this massive flow of information no more than about 40 bits per second actually reaches consciousness
A fascinating example of this pre-conscious processing can be found in a phenomenon known as blindsight. It became a topic first of curiosity and then of medical concern during the First World War, when medics noticed that certain soldiers who had been blinded by a bullet or shell wound to the visual cortex (but whose eyes remained intact) were nonetheless ducking their heads when an object, such as a ball, was tossed over their heads. How could these blind soldiers ‘see’? They were seeing with a more primitive part of the brain. When light enters your eye its signal follows the pathways back to your visual cortex, a relatively new part of the brain. However, part of the signal also passes down through an area called the superior colliculus, which lies underneath the cortex, in the midbrain . The superior colliculus is an ancient nucleus that was formerly used for tracking objects, like insects or fast-moving prey, so that our reptilian ancestors could, say, zap it with their tongues. Now largely layered over by evolutionarily more advanced systems, it nonetheless still works. It is not sophisticated: it cannot distinguish colour, discern shape or recognise objects, the world appearing to the superior colliculus much like an image seen through frosted glass. But it does track motion, capture attention and orient the head towards a moving object. And it is fast. Fast enough, according to some scientists, to account for a batter or infielder’s rapid tracking of a moving ball. Lastly, blindsight operates without us ever being aware of it.
Colin Camerer, George Loewenstein and Drazen Prelec, three of the founders of the new field of neuro-economics, have surveyed this research and summarised the differences between the two types of brain processing, labelling them automatic and controlled thought.
Pattern recognition, even though silent, probably draws on higher brain regions, parts of the neo-cortex and the hippocampus, a brain region acting as the filing system for memories
When the body wants to send a signal at high speed it uses electrical signals rather than blood-borne chemical ones like hormones. But nerve fibres vary dramatically in their speed of transmission, so the body and brain choose carefully the fibres they entrust with a message. The fibres of the nervous system that connect visceral organs to brain are relatively slow, carrying their signals at speeds ranging from 5 to 30 metres per second, with some ambling along at a mere one metre per second. However, the muscular nervous system is made up of a different class of fibre altogether, and these carry signals at close to 120 metres per second. If we were to compare our body’
as a challenging event unfolds. Our muscles, especially our facial muscles, kick in quickly and unreflectively, in a matter of milliseconds. Shortly thereafter the visceral nervous system, operating on the order of milliseconds to seconds, calls into action the tissues and organs, such as lungs, liver, adrenal glands, that will support our muscles during the crisis. Moments after these two electrical systems have been brought online our chemical systems beginJ to switch on. Fast-acting hormones like adrenalin, released in seconds to minutes, flood into the blood and unpack energy stores for immediate use. Finally, if a challenge persists, then our steroid hormones take charge, and over the course of hours, even days, they prepare our bodies for a change of life. At this point our bodies retool, girding for attack or hunkering down for a siege. Each of these staggered physical changes is reported back to the brain, where it alters our emotions, moods, memories and thoughts.
Our visceral nervous system is composed of two branches: the fight-or-flight system and the rest-and-digest system. The fight-or-flight nerves thus work largely (but not always, as we will see in a later chapter) in opposition to those of the rest-and-digest system, the two nervous systems alternating their activities, one speeding us up, the other slowing us down.
The main nerve in the rest-and-digest nervous system is the vagus, a large and powerful nerve that exerts a calming influence on the many tissues and organs it touches. The word ‘vagus’ (pronounced like Vegas) is Greek for wanderer, and wander this nerve does. It emerges from the brain stem and heads down into the abdomen. In the course of its long travels it visits the voicebox, then the heart, lungs, liver and pancreas, finally terminating in the gut. Because of its extensive connections, this curious nerve can modulate our tone of voice, slow our breathing and heart rate, and in the stomach control the early stages of digestion. What is more, the region of the brain stem where the vagus originates is also the one that regulates our facial muscles, and this allows our facial expressions to synchronise with our heart rate and the state of our gut. By linking facial expression, voice, lungs, heart and stomach, the vagus plays a central role in our emotional lives.
It also brings messages back to the brain: almost 80 per cent of the vagus nerve’s fibres (the vagus is a cable composed of thousands of fibres) carry information from body to brain. Most of this returning information comes from the gut, so one may naturally ask, do gut feelings really come from the gut? The quick answer is yes, or least some of them do. Not all, though.
The gut is under the command of what is called the enteric nervous system , which controls the movement and digestion of nutrients as they pass through the stomach and intestines. Unlike other nerves in the body, this nervous system can act independently of the brain, and is one of the only systems that will continue to function even if all connection to the brain is severed. It contains approximately100 million neurons, more than are found in the spinal cord, and produces the same neurotransmitters as the brain. The enteric nervous system has been aptly termed by Michael Gershon ‘ the Second Brain’.
According to Shannon, the amount of information contained in a signal is proportional to the amount of novelty – or, put another way, the amount of uncertainty – in it. That may seem counter-intuitive. Uncertainty seems the antithesis of information. But what Shannon meant was this: real information should tell us something we do not already know; it should therefore be unpredictable.
When we plan an action our neo-cortex sends a copy of this plan to the cerebellum, which then dampens or even cancels out the sensation it expects to result. Because of this dampening we are largely unaware of, say, our arms moving back and forth when we walk, or the chafing of our own clothes on our skin. It is also the reason we are unable to tickle ourselves: since we have produced the motion of fingers on ribcage, our cerebellum dampens the expected sensation; we may still feel our fingers on our skin, but we are not surprised, so the tickling has no effect.
We too lose sight of objects if they do not move, an effect known as Troxler fading, after a nineteenth-century German physiologist who noted that we gradually lose awareness of unchanging visual stimuli, just as we do the constant sound of background traffic.
'Highway hypnosis’ or ‘ the moth effect’. Drivers on long, featureless stretches of road or driving through the night can become so starved for stimulation that they attend almost hypnotically to the rare appearance of a light beside the road, often a police car with lights flashing, and then proceed to drive straight into it
When the alarm centre of your brain is tripped, neurons in the locus ceruleus, located in the brain stem, boost their firing rate and spray a neuromodulator called noradrenalin throughout your brain. Neuromodulators are a type of neurotransmitter – the chemicals used to bridge the synaptic gap between neurons so an electrical message can jump from one to the other – but of a very particular kind. They do not participate in any specific brain activity, like doing maths or speaking French or remembering the dates of the Punic Wars; rather they alter the sensitivity of neurons throughout the brain, making them fire more easily or more rapidly. The effect noradrenalin has on neurons can be compared to that of turning up the lights in a room and the volume on a microphone.
Low levels of information, such as we encounter in a dull conversation, leave us bored and sleepy, while high levels of complexity, such as we might find in a movie with a difficult-to-follow plot or in an overload of files at work, confuse us and promote a state of anxiety. But just the right amount of information piques our curiosity, quenches our thirst for novelty, and provides a diffuse feeling of satisfaction that spreads
Almost every recreational drug, be it alcohol, cocaine or amphetamine, achieves its addictive effects by increasing the action of dopamine in a region of the brain called the basal ganglia, located midway between the brain stem and the cortex, and specifically in one part of it called the nucleus accumbens
Food can raise an animal’s dopamine levels by 50 per cent, sex by 100 per cent. However, nicotine can raise them by 200 per cent, cocaine by 400 per cent, and amphetamine by 1,000 per cent
The amount of dopamine released into the nucleus accumbens does not depend on the absolute amount of reward an animal receives, but on how unexpected it is. This further suggests that we enjoy and crave environments in which we receive unexpected rewards; in other words, we enjoy risk
John Maynard Keynes, more than any other economist, understood these subterranean urges to explore, calling them ‘animal spirits’ – ‘a spontaneous urge to action rather than inaction’. He considered them the pulsing heart of the economy. ‘It is a characteristic of human nature,’ he wrote, ‘that a large proportion of our positive activities depend on spontaneous optimism rather than on a mathematical expectation.’ Should this spontaneous optimism falter and animal spirits dim, leaving us with nothing but mathematical calculation, then, he warned, ‘enterprise will fade and die’. He suspected that business enterprise is no more driven by the calculation of odds than is an expedition to the South Pole. Enterprise is driven to a great extent by a pure love of risk-taking.
It is a core principle of formal finance that higher returns come only by taking greater risk, and much the same can be said of our ancient search and hunting patterns. Dopamine prompted us to try things we had not tried before, and in so doing led us to stumble upon valuable territories and hunting techniques that otherwise would have remained undiscovered
Unlike adrenalin, for example, which is pre-produced and stored in little pouches called vesicles, waiting to be released, steroids cannot be stored. Steroids are molecules that can cross cell membranes, even permeate skin (many steroids, such as testosterone, are applied as a gel) or penetrate the rubber gloves of lab technicians. Trying to hoard steroid molecules in a vesicle would be like trying to lock ghosts in a room – they would just drift through the cell walls
The hormone signalling process, from hypothalamus to the production of steroid hormone, takes up to fifteen minutes just to get started.
It takes even longer for steroids to take effect – hours, even days. The process may be slow, but the way steroids work is unique in the human body. They cross membranes, enter the cell nucleus, and cause gene transcription. In other words, steroids cause proteins, the building blocks of the body, to be manufactured. Furthermore, unlike other hormones which generally have effects localised to one or two tissues, steroids have receptors in almost every nucleated cell in the body. All these properties of steroids give you an inkling of their power. A single steroid like testosterone can cause a bewildering suite of physiological changes, building up bone density and lean-muscle mass, increasing haemoglobin and clotting agents in your blood, heightening mood, tormenting you with sexual fantasy, and tilting behaviour towards greater risk-taking.
The default sex of all foetuses is female: unless they have a Y chromosome, they will develop into females. The Y chromosome is a surprisingly simple one, with very few genes on it. One of these is responsible for the bulk of the differences between men and women. This gene is called SRY, standing for Sex Determining Region of the Y chromosome.
What the SRY gene does is simple. It codes for the building of a protein hormone called Testis-Determining Factor, which shunts the primordial gonads off the path leading them to develop into ovaries and onto a path leading them to develop into testes. Once they start to grow, the testes produce testosterone, and this molecule creeps out into the bloodstream and does all the rest of the work, docking in receptors throughout the body and morphing tissues into a male rather than female form
Our chromosomes do much the same thing when they recombine – they exchange old and broken genetic parts for new ones. An X chromosome can swap material with another X chromosome, thus ensuring that each generation is fitted with new parts. But not so the isolated Y. This lone wolf has nothing it can swap with, so over time, like a car that is never serviced, it compounds problems and accumulates damage until its genes, one by one, die off. Some animals, such as the kangaroo, now have only a few genes remaining on their Y chromosome. This slow death of the Y has been called Adam’s Curse by the Oxford geneticist Bryan Sykes, who predicts that in 5,000 generations men will be extinct.
Developmental biologists distinguish between the anabolic and the masculinising effects of testosterone. Masculinising effects include the growth of facial hair, the lowering of the voice, and the growth of testicles and sperm-producing cells. The anabolic effects include an increase in lean-muscle mass, in haemoglobin, and in bone density. It is the anabolic effects that athletes are after when they illicitly take steroids.
....group of football players, and found that their ability and success could be predicted from the lengths of their index and ring fingers, and specifically from the ratio of the two. This ratio, known as 2D:4D, meaning second digit length divided by fourth, could predict sporting ability because, Manning claimed, it gauged the amount of testosterone the athletes had been exposed to in the womb, a longer ring finger relative to index indicating higher androgen exposure
Almost every crash in the history books, at least those occurring in the US and UK, has taken place in the autumn, and most of those in October. The Panic of 1907, the Crash of 1929, Black Monday of 1987, the Crash of 1997 (related to the Asian Financial Crisis), the crashes of both 2007 and 2008 (related to the Credit Crisis) – all took place in October. It was thought in the nineteenth century and the early twentieth that crashes occurred in the autumn because farmers, needing cash for the harvest, withdrew their money from banks, causing bank runs and stock crashes
CRH (short for corticotropin-releasing hormone). CRH in the brain instils anxiety and what is called ‘anticipatory angst’, a general fear of the world leading to timid behaviour. Together with cortisol, it also suppresses the production of testosterone, the invigorating hormone that powered so much of Scott’s confidence, exploratory
chronically raised heart rate and blood pressure, a condition known as hypertension. The unceasing pressure on arteries that comes with hypertension can cause small tears in arterial walls, tears which then attract healing agents called macrophages or, more commonly, white blood cells. Mounds of these sticky clotting agents grow over the arterial injuries, and subsequently trap passing molecules, like fats and cholesterol. Larger and larger plaques form, which can become calcified, a condition known as atherosclerosis, or hardening of the arteries. As the plaques grow and block arteries, they decrease blood flow to the heart itself, causing myocardial ischemia, or angina, a recurring pain in the chest. If the plaques become large enough they may break off, producing a thrombus, or clot, which then travels downstream to smaller and smaller arteries, and ends up blocking an artery to the heart, causing a heart attack, or an artery to the brain, causing a stroke.
Cortisol is the molecule of irrational pessimism. can we turn off the cortisol? Can we control its toxic body–brain feedback loop? Sadly the answer is: only with very great difficulty.
One way to tame these tidal waves of risk-taking and keep life on the trading floor safely between the tidelines is to institute a bonus scheme that pays traders once a business cycle (approximately four to five years), instead of once a year. If traders are profitable over a few years, they can begin to draw on their bonus pool
The phrase ‘ghost in the machine’ was in fact coined by the Oxford philosopher Gilbert Ryle when discussing Cartesian dualism in his book The Concept of Mind (1949).
In the Phaedo, 65, Plato had claimed that thought is best conducted in the absence of bodily influences. In De Anima, 1.ii, Aristotle on the other hand argued: ‘the soul seems unable to have anything done to it, or to do anything, without the body; this is so, for instance, with regard to feeling anger, confidence, or desire, and with sensation in general. What seems most likely to be peculiar to the soul is thought; but, if even this is a kind of imagination, or at least does not occur without imagination, then not even it can occur independently of the body.’
The true measure of our superior brain relative to animals is one called the encephalisation quotient.
Tom Stafford and Matt Webb (2005) Mind Hacks: Tips and Tools for Using Your Brain