Innholdsfortegnelse for EG12 i New Scientist - The Essential Guides

“A fascinating but elusive phenomenon; it is impossible to specify what it is, what it does, or why it evolved. Nothing worth reading has been written about it”. So wrote psychologist Stuart Sutherland of consciousness in the International Dictionary of Psychology a little over three decades ago. Much has changed in the past years. Imaging technologies have given fresh insights into what goes on in the brain as we experience sensations from love to colour to hunger to fear. Biologists have traced where subjective experience first appeared in the tree of life, and the sensations other animals have. Mathematical models are providing new angles on consciousness. But in all this, there is much we still don’t understand about consciousness and its place in the cosmos – not least, the “hard problem”…

A QUICK glance at the thousands of books that purport to explain consciousness makes the real understanding of it look like a Herculean task. There is, after all, a profound explanatory gap between neural activity of any sort and subjective feelings. The first belongs to the realm of physics, to space and time, energy and mass; the second to experience. And while experiences are ephemeral, they are the very stuff of life. The only way we know about the world, about space and time, about energy and mass, about anything in fact is by seeing, hearing and smelling, by lusting and hating, by remembering and imagining. That these two realms are closely related is revealed by the effects of a stroke, a strong blow to the head or a neurosurgeon electrically…

Our assessment of the degree to which something is conscious is necessarily anthropocentric, as we can go only on our – highly imperfect – understanding of what consciousness is and what it relates to in ourselves. But some or all of these characteristics in other animals are often seen as indicating some degree of inner life. Recognises itself in a mirror Has insight into the minds of others Displays regret at having made a bad decision Heart races in stressful situations Has many dopamine receptors in its brain to sense reward Highly flexible in making decisions Has ability to focus attention (selective experience) Needs to sleep Is sensitive to anaesthetics Displays unlimited associative learning…

IF THE subjective feeling of consciousness is an illusion created by brain processes, then machines that replicate such processes would be conscious in the way that we are. How would we know this? Daniel Dennett at Tufts University in Massachusetts says a Turing test, in which a machine has to convince a human interrogator that it is conscious, should, if conducted “with suitable vigour and aggression and cleverness”, be enough. Michael Graziano at Princeton University thinks we could take a more direct approach. His attention schema hypothesis sees consciousness as the brain’s simplified model of its own workings – a representation of how it represents things. He believes it is possible to build a machine that possesses a similar self-reflective model. “If we can build it in a way that…

A sense of existence is essential to consciousness as we experience it. There is something it is like to be us, and perhaps to be a scrub jay, or an octopus, or a newborn child. Presumably, there is nothing it is like to be a table or an iPhone. Self-awareness and its related trait of metacognition, the ability to monitor your own mental states and those of others, are often regarded as the pinnacles of consciousness. In fact, they might be evolutionary accidents, and perhaps even figments of our own imaginations.…

Some people swear that if they want to wake up at 6 am, they just bang their head on the pillow six times before going to sleep. Nonsense? Maybe not. A study from 1999 shows that it all comes down to some nifty unconscious processing. For three nights, researchers at the University of Lübeck in Germany put 15 volunteers to bed at midnight. They either told the participants they would wake them at 9 am and did; told them they would wake them at 9 am, but actually woke them at 6 am; or said they would wake them at 6 am and did. This last group had a measurable rise in the stress hormone adrenocorticotropin from 4:30 am, peaking around 6 am. People woken unexpectedly at 6 am had…

Sleep occurs in repeating cycles, each about 90 minutes long. In a cycle, there are three stages of non-REM sleep, where brain activity becomes gentle and rhythmic, eventually heading into slow-wave, deep sleep. After slow-wave sleep, the brainwaves change pattern again, the eyes start roiling under their lids and most of the muscles in the body become paralysed to stop us acting out our dreams. This is REM sleep, and the proportion of time spent in this stage increases in each successive sleep cycle throughout the night, so that by early morning, much of those 90 minutes can be spent in REM. We do dream in other stages of sleep, but these dreams tend to be unemotional, concerned with simple things and hard to remember. In short, they are boring.…

In the 1964 film Dr Strangelove, the lead character had an unusual affliction: his right arm seemingly had a mind of its own. Such a condition really does exist, although it is vanishingly rare. People with so-called alien hand syndrome find that their affected limb reaches out and grabs things they have no wish to pick up. They might try restraining it with their other hand, and if that doesn’t work, “they sometimes come to the surgery with their hand tied up”, says Sergio Della Sala, a neuroscientist at the University of Edinburgh, UK, who studies the condition. The cause is injury to the brain, usually in a region known as the supplementary motor area (SMA). Work on monkeys has shown that another part of the brain, the premotor cortex,…

ON 15 April 1987, Michelle Francl-Donnay’s husband Tom was due to pick her up from an evening meeting, but decided to take a swim first. He had an undiagnosed heart condition, and while in the pool had a catastrophic aneurysm. Michelle rode with him in the ambulance. That was the last time she spoke to him. “When I saw Tom’s body the next morning, he clearly wasn’t there anymore,” says Francl-Donnay, a chemist at Bryn Mawr College in Pennsylvania and an adjunct scholar at the Vatican Observatory who writes extensively on both science and spirituality. Over the years, she found herself mulling a question humans have asked for a long time: where had he gone? Even those of us who rationally reject the idea of an afterlife have trouble letting…

WHIMS, memories, hopes, judgements, morals, qualms – all coming together to influence decisions. It is sometimes hard for us to understand how we reach the decisions we do. For fundamental physicists, it is a complete mystery. Our decision-making ability, rooted in our conscious experience of the world, is a not-so-secret superpower to alter the physical world, changing its evolution apparently at will. That is something no physical law yet devised can explain, and it leads to a question at the sharp end of considerations of the relationship between consciousness and the external world. “We act, we decide, we initiate actions,” says Carlo Rovelli at Aix-Marseille University in France. “How can we insert this agency into the general picture of nature?” Agency seems to exist on a similar sort of spectrum…

THE subjective nature of consciousness makes it difficult even to define. The closest we have to a consensus is that there is “something it is like to be conscious”. There is something it is like to be me or you, and probably something it is like to be a dolphin or a mouse. But there is – presumably – nothing it is like to be a bacterium or a toy robot. The challenge is to understand how and why this can be true. How do conscious experiences relate to the cells and molecules and atoms inside brains and bodies? Why should physical matter give rise to an inner life at all? Some people fear science may not be up to the task. They point out that you can’t precisely control…

CONSCIOUSNESS is a slippery concept. It isn’t just the stuff in your head; it is the subjective experience of some of that stuff. When you stub your toe, your brain doesn’t merely process information and trigger a reaction: you have a feeling of pain. Being in pain; experiencing joy; smelling onions frying; feeling humiliated; recognising a friend in the crowd; reflecting that you are wiser than you were last year – all of these are examples of conscious experiences, sometimes termed “qualia”. The mysteries starts with what those experiences are made of. In the 1600s, the philosopher René Descartes famously divided the universe into “mind stuff” (res cogitans) and “matter stuff” (res extensa), raising the conundrum of how the two might ever interact. He was convinced that the body and…

We know – or we think we know – that we are conscious. But how about your pet dog or cat, or a tool-making crow, or a playful octopus or writhing worm? It might seem impossible to answer these questions. We have yet to identify any distinctive pattern of brain activity that indicates consciousness even in humans, and we can hardly ask other animals about their experiences. But posing these questions does provide another way to approach the phenomenon of consciousness. By asking what its outward signs are, and tracing back where they first appeared in the history of life, we might begin to understand why consciousness exists – and so learn a little about more what it is.…

ENGINEERING, and the science of robotics in particular, tells us that every good control device needs a model – a quick sketch – of what it controls. We already know from cognitive neuroscience that the brain constructs many internal models, bundles of information that represent items in the real world. These models are simplified descriptions, useful but not entirely accurate. For example, the brain has a model of the body, called the body schema, to help control movement of the limbs. When someone loses an arm, the model of the arm can linger on in the brain so that people report feeling a ghostly, phantom limb. But the truth is, all of us have phantom limbs, because we all have internal models of our real limbs that merely become more…

MANY psychologists and anthropologists hold to the idea that there is a hierarchy of consciousness that corresponds with increasing brain complexity. At its base is the minimal consciousness attributed to animals with simple nervous systems. These minds are thought to be permanently adrift in a sea of raw sensory experiences, tossed around between perceptions such as colour, hunger, warmth and fear, with little awareness of their meaning. ← Turn back to chapter 2 for more on animal minds Few minds are sophisticated enough to experience the world differently – through an introspective lens. Even then, they may have a limited sense of self. Only at the peak of mental complexity do we find minds able to construct a lifelong narrative of experiences centred around an abstract concept of “self”. These…

YOUR pet dog, if you have one, is probably aware of many sensations at any given moment: that it is hungry, that it is tired after a long walk, perhaps, and that there is a delicious smell emanating from the kitchen. As its owner, however, you are aware of all those sensations and yet have an extra level of thought processes overlaying them. As a human, we can be aware that we are aware of our basic sensory inputs, and that allows us to reflect on the accuracy or validity of our feelings and judgements. That lets us think: “How tired I am after that long walk, it’s that satisfying kind of tiredness you get after exercise. But I’m not too tired to walk to the pub tonight.” This faculty…

It is the brain’s natural twilight zone – a halfway stage between wakefulness and sleep that we all experience as we drop off. Known as hypnagogia or “N1”, it is often characterised by vivid dreams – although usually people progress into deep sleep and forget the dreams when they wake. It repays closer attention. “If you are a good observer, you will notice that those spots have a hallucinoid quality to them,” says Tore Nielsen, a sleep researcher at the Montreal Sacred Heart Hospital in Canada. We don’t know what causes hypnagogia, but one idea is that some parts of the brain are falling asleep ahead of the rest. “It’s known that different parts of the brain tune out at different times,” says Nielsen. It has long been thought that…

Consciousness isn’t an on-off state, but more like a dimmer switch. Or perhaps you might view it as a ladder of states, with zero consciousness at the bottom and maximum consciousness at the top. Many altered states of consciousness exist, from induced unconsciousness in the form of anaesthesia to hallucinatory states that, besides being induced by drugs, occur naturally in many of us. And even with states regarded as minimally conscious, from comas to a persistent vegetative state, it seems things aren’t as clear-cut as we once thought.…

From magic mushrooms and ayahuasca – a potion used in South America during certain religious rites – to LSD and ketamine, using chemical means to achieve altered, hallucinogenic states of consciousness has been part of human culture for millennia. In recent years, such mind-altering drugs have been an increasing focus of medical attention as a treatment for conditions such as depression and post-traumatic stress disorder. Only recently have we discovered how these experiences are produced, however. In 2016, researchers at Imperial College London monitored brain activity in 19 volunteers who had taken ketamine, 15 who had consumed LSD and 14 who were under the influence of psilocybin, a hallucinogenic compound in magic mushrooms. The scans showed that the volunteers’ hallucinations arose from the combined activity of brain regions that don’t…

AS RECENTLY as the late 1990s, it was assumed that people in a vegetative state, by definition, had no conscious awareness. They would show signs of sleep and wake cycles, and occasionally open their eyes or make involuntary movements, but weren’t aware of themselves or the people around them. However, Adrian Owen, then at the MRC Cognition and Brain Sciences Unit in Cambridge, UK, had a worrying thought: what if we were wrong? Neurologists have long been aware of locked-in syndrome, in which people are awake and aware but unable to move almost all of their body. It was first defined in medical textbooks in 1966, but must have been known about much earlier; it was described in Alexandre Dumas’s 1844 tale, The Count of Monte Cristo. People who are…

DUALISM Brain and mind are two separate things, and conscious experiences can’t, in all probability, be fully explained through the workings of physical matter. MONISM Brain and mind are the same thing, and consciousness is ultimately a phenomenon that derives from the workings of matter – in humans, the matter of the brain. The dominant subgenre of monism today is… PHYSICALISM Existing laws of physics governing electrical and chemical signalling in our brains are ultimately enough to explain consciousness and the workings of our minds. Understand these workings, and we should be able to “see” the physical markers of different conscious experiences, and so know what other people are experiencing. PANPSYCHISM Deriving from the idea that consciousness is a fundamental component of the universe in its own right, this suggests…

CONSCIOUSNESS could have evolved for multiple reasons – or perhaps none. Some think that, rather than having a survival advantage, it is an “epiphenomenon”, simply emerging as an automatic property of intelligence. For most, however, that is a bit of a copout. “My guess is that consciousness, because of its complexity and costliness, in fact conferred adaptive value on its possessors,” says David Barash, a psychologist at the University of Washington in Seattle. Tracking the evolution of what we call consciousness has its own difficulties, however. “Consciousness doesn’t leave any fossil record,” says Anil Seth at the University of Sussex, UK. We must infer its evolutionary history by comparing animals alive today and working back to what their common ancestor might have been able to do. But because we don’t…

To avoid searching for traits specific to humans in other animals, Jonathan Birch, a philosopher at the London School of Economics, and his colleagues suggest we should concentrate on five broad aspects of conscious experience that can be used to distinguish different animals’ degree of consciousness. PERCEPTUAL RICHNESS How well an animal can discriminate different details in each of its senses. EVALUATIVE RICHNESS Broadly speaking, the capacity to differentiate between positive rewards and noxious stimuli, which could be analogous to human emotions such as pleasure or pain. UNITY The extent to which an animal integrates the information from its sensory organs into a single experience. TEMPORALITY Whether a creature’s past experience influences its present behaviour, and whether it can plan for the future and make decisions. SELFHOOD This may be…

ON THE face of things, it seems obvious that we sleep so our brains and bodies can rest and recuperate. But why not rest while conscious, so that we can also watch out for threats? And if recuperation means things are being repaired, why can’t that take place while we are awake? Scientists who study how animals eat, learn or mate are unburdened by questions about the purpose of these activities. But for sleep researchers, the “why” is maddeningly mysterious. Sleep is such a widespread phenomenon that it must be doing something useful. Even fruit flies and nematode worms experience periods of inactivity from which they are less easily roused, suggesting sleep is a requirement of the simplest of animals. But surveying the animal kingdom reveals no clear correlation between…

IT WAS a Japanese surgeon who performed the first known surgery under anaesthetic, in 1804, using a mixture of potent herbs. In the West, the first operation under general anaesthetic took place at Massachusetts General Hospital in 1846. A flask of sulphuric ether was held close to the patient’s face until he fell unconscious. Since then, a slew of chemicals have been co-opted to serve as anaesthetics, some inhaled, like ether, and some injected. The people who gained expertise in administering these agents developed into their own medical speciality. Although long overshadowed by the surgeons who patch you up, the humble “gas man” does just as important a job, holding you in the twilight between life and death. The development of general anaesthesia has transformed surgery from a horrific ordeal…

THERE is no lack of rare conditions that seem to suggest altered states of consciousness. Take phantom limb syndrome – the sensation some people have that their missing limb is still present – or Cotard syndrome, in which people believe they are dead. Or calendar synaesthesia, perhaps one of the most striking examples of how the body and brain interact to shape our minds. When most people think about what they plan to do in November, say, they have a hazy concept of the months ahead. But people with calendar synaesthesia can actually see a calendar in front of them, often in a strange formation – a hula hoop that touches them in the centre of their chest, for instance. Neuroscientist V. S. Ramachandran, who has studied calendar synaesthesia and…

BRAIN DEAD A person is brain dead when they no longer have any brain activity. They won’t regain consciousness or be able to breathe without artificial life support. COMA Someone in a coma is unconscious and has low levels of brain activity. They will be unresponsive to sound and pain and will have greatly reduced reflexes, such as swallowing or coughing. They may be able to breathe on their own. VEGETATIVE STATE A state in which a person may have some reflexes, including yawning and eye movements, but shows no awareness of themselves or their environment. MINIMALLY CONSCIOUS As a person begins to show intermittent awareness of themselves or their environment, they are said to be in a minimally conscious state. As they develop the ability to communicate, they are…

Consciousness is all we have, but what is its place in the world? The relationship between our internal world and the external one is another of the great mysteries of consciousness with as yet few answers. It is a conundrum with two sides. The first, already touched on, is how the physical processes that we understand to underlie the workings of reality contrive to make conscious experience. The second is the role consciousness itself plays in constructing reality – which is where matters become very murky indeed.…

THE unique difficulty of the hard problem of consciousness stems from the inherently subjective nature of felt experience. Whatever it is, you might think, it isn’t something you can prod and measure – not a natural fit for our mathematically based models of physical phenomena. Then again, mathematics has a track record with hard problems. Physicist Eugene Wigner coined the phrase the “unreasonable effectiveness of mathematics” in the 1960s to encapsulate the curious fact that merely by manipulating numbers, we can describe and predict all manner of natural phenomena with astonishing clarity, from the movements of planets and the strange behaviour of fundamental particles to the consequences of a collision between two black holes billions of light years away. That success is down to the ability of mathematics to translate…