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Day to Day Behaviour Programmed by Evolution |
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How much free choice do we in fact have? |
| Research discovers 'generosity hormone'
The reason why some people are more generous than others is down to levels of a single hormone in the brain. Daily Telegraph 07/11/2007 A new study suggests that those who give more to charity, open their wallets and act kindly to strangers have higher than normal levels of oxytocin hormone in the brain, while mean-spirited people have relatively lower levels. The brain chemical could explain one of the most important traits of human, as opposed to animal society: we are altruistic towards people we do not know, are proud of being Good Samaritans, and are generous and charitable when we do not have to be. advertisementThe new study of the hormone is published by Prof Paul Zak of Claremont Graduate University in PLoS ONE, and colleagues, extending work linking the same hormone to levels of trust, revealing what he said is a "huge increase" in generosity linked to higher levels of oxytocin. His team gave doses of oxytocin and a placebo to participants, who were then offered a decision on how to split a sum of money with a stranger who could accept or reject the split. The results were overwhelming: Those given oxytocin offered 80 per cent more money than those given a placebo. There is even evidence that brain oxytocin levels in society are increasing, as annual levels of charity in American have gone up 187% since 1954. But this is not because genes responsible for high oxytocin are spreading, or because people are inhaling the chemical, but it is because the hormone is made at greater levels as a result of touching, receiving signals of trust from other people, or when presented by advertisers with an image that touches the heart strings, such as a photograph of a poverty-stricken child. "Oxytocin specifically and powerfully affected generosity using real money when participants had to think about another's feelings," Prof Zak explains. "This result confirms our earlier work showing that oxytocin affects trust, but with a dramatically larger effect for generosity." As for data on average oxytocin levels in Scots, who have a reputation for meanness, he said he had "no data." Oxytocin's effect on generosity is more than three times larger than observed in the work he published in Nature in 2005 with colleagues in Zurich, showing that people who inhaled an oxytocin nasal spray are more likely to trust a stranger with their cash. "Trust with oxytocin goes up 17%," said Prof Zak, "but in the present paper we show generosity increases 80% with oxytocin." The paper was co-written by Angela Stanton of Claremont Graduate University and Sheila Ahmadi of UCLA's Geffen School of Medicine. As for fears about the abuse of oxytocin by snake oil salesmen, Prof Zak said: "we have to put a lot up people's noses to get an effect (about two teaspoons worth) - not a lot of oxytocin gets into the brain, so lots needs to be used, so spritzing it around won't have an effect." Good causes who want to boost their takings this way should beware of other side effects: 20 percent of the men who take it get erections, and pregnant women would want to avoid it because it could trigger contractions. Besides, Prof Zak said that oxytocin sprays are unnecessary: con men, sales people and advertisers already know how to use powerful images to boost oxytocin levels in the brain. |
| Study finds left-wing brain, right-wing
brain Even in humdrum nonpolitical decisions, liberals and conservatives literally think differently, researchers show. By Denise Gellene Los Angeles Times Staff Writer September 10, 2007 Exploring the neurobiology of politics, scientists have found that liberals tolerate ambiguity and conflict better than conservatives because of how their brains work. In a simple experiment reported todayin the journal Nature Neuroscience, scientists at New York University and UCLA show that political orientation is related to differences in how the brain processes information. Previous psychological studies have found that conservatives tend to be more structured and persistent in their judgments whereas liberals are more open to new experiences. The latest study found those traits are not confined to political situations but also influence everyday decisions. The results show "there are two cognitive styles -- a liberal style and a conservative style," said UCLA neurologist Dr. Marco Iacoboni, who was not connected to the latest research. Participants were college students whose politics ranged from "very liberal" to "very conservative." They were instructed to tap a keyboard when an M appeared on a computer monitor and to refrain from tapping when they saw a W. M appeared four times more frequently than W, conditioning participants to press a key in knee-jerk fashion whenever they saw a letter. Each participant was wired to an electroencephalograph that recorded activity in the anterior cingulate cortex, the part of the brain that detects conflicts between a habitual tendency (pressing a key) and a more appropriate response (not pressing the key). Liberals had more brain activity and made fewer mistakes than conservatives when they saw a W, researchers said. Liberals and conservatives were equally accurate in recognizing M. Researchers got the same results when they repeated the experiment in reverse, asking another set of participants to tap when a W appeared. Frank J. Sulloway, a researcher at UC Berkeley's Institute of Personality and Social Research who was not connected to the study, said the results "provided an elegant demonstration that individual differences on a conservative-liberal dimension are strongly related to brain activity." Analyzing the data, Sulloway said liberals were 4.9 times as likely as conservatives to show activity in the brain circuits that deal with conflicts, and 2.2 times as likely to score in the top half of the distribution for accuracy. Sulloway said the results could explain why President Bush demonstrated a single-minded commitment to the Iraq war and why some people perceived Sen. John F. Kerry, the liberal Massachusetts Democrat who opposed Bush in the 2004 presidential race, as a "flip-flopper" for changing his mind about the conflict. Based on the results, he said, liberals could be expected to more readily accept new social, scientific or religious ideas. "There is ample data from the history of science showing that social and political liberals indeed do tend to support major revolutions in science," said Sulloway, who has written about the history of science and has studied behavioral differences between conservatives and liberals. Lead author David Amodio, an assistant professor of psychology at New York University, cautioned that the study looked at a narrow range of human behavior and that it would be a mistake to conclude that one political orientation was better. The tendency of conservatives to block distracting information could be a good thing depending on the situation, he said. Political orientation, he noted, occurs along a spectrum, and positions on specific issues, such as taxes, are influenced by many factors, including education and wealth. Some liberals oppose higher taxes and some conservatives favor abortion rights. Still, he acknowledged that a meeting of the minds between conservatives and liberals looked difficult given the study results. "Does this mean liberals and conservatives are never going to agree?" Amodio asked. "Maybe it suggests one reason why they tend not to get along." |
| Scientists discover brain trigger for
selfish behaviour Scientists have found that they can make people selfish and egotistical by turning off a brain region at the flick of a switch, providing new insight into social behaviour Telegraph.co.uk 6/10/2006 They set out to show that activation of the area of the brain known as the dorsolateral prefrontal cortex (DLPFC) triggers self-control. The scientists used repetitive transcranial magnetic stimulation on subjects, in which a weak magnetic field was used to temporarily disable the DLPFC. advertisement Then they took part in a bargaining game in which two individuals had to agree on the division of a given amount of money. One person proposed an offer and the other could either accept or reject it — but rejection meant that neither got any money. The researchers found that suppressing the right side of the DLPFC made the volunteers more likely to accept unfair offers instead of rejecting them in order to punish the "proposer" for not sharing more equally. Subjects who had the right DLPFC turned off were far less able to keep their selfish impulses under control, though they still knew what was fair and what was not. "Our study suggests that right, but not left, DLPFC is involved in overriding selfish impulses while it does not affect subjects' fairness judgements," said Prof Ernst Fehr, an economist. The insight into the brain circuits that regulate selfish impulses is published today by Prof Fehr and the neuroscientist Prof Daria Knoch, of Zurich University, with Prof Alvaro Pascual-Leone, of Harvard. Prof Knoch dismissed fears about the unethical use of the method, saying that the effect was of only short duration and required the permission of the person undergoing the stimulation. Earlier studies using a brain scanner method had suggested that self-control depended on the DLPFC, which is among the last brain areas to mature. The new research, published in the journal Science, points out that the same part of the brain is not fully developed in young people, which could account for their notoriously selfish behaviour. Human society depends on fairness, co-operation, politeness, punctuality, and honesty — and on punishing those who violate these norms. |
| Different view for East and West
Western and Eastern people look at the world in different ways, University of Michigan scientists have claimed. BBC online 22 Aug 2005 Researchers compared the way 26 Chinese and 25 US students viewed photographs of animals or inanimate objects set against complex backgrounds. Westerners' eyes tended to focus on the main subject while the eyes of their Eastern counterparts kept flicking to background details, they said. The study is published in Proceedings of the National Academy of Sciences. Its findings appear consistent with previous research which has suggested Eastern people think in a more holistic way than Westerners, instinctively paying greater heed to context. In contrast, Westerners were thought to be more focused and analytical. The latest study found that to start with, both American and Chinese students fixed mainly on the background. But after 420 milliseconds the Americans began to concentrate their attention more on the foreground objects. This was not true for the Chinese, who kept throwing glances at the background. Memory differences The researchers also tested the ability of volunteers to remember previously seen foreground objects when they were superimposed against new backgrounds. The Chinese students were more likely to forget they had been shown an object before. In their memory, the foreground object and its original background appeared to be bound together. The researchers, led by Dr Richard Nisbett, wrote: "The Americans' propensity to fixate sooner and longer on the foregrounded objects suggests that they encoded more visual details of the objects than did the Chinese. "If so, this could explain the Americans' more accurate recognition of the objects even against a new background." The researchers suggested social practices may play a role in the differing approaches. "East Asians live in relatively complex social networks with prescribed role relations. "Attention to context is, therefore, important for effective functioning. "In contrast, Westerners live in less constraining social worlds that stress independence and allow them to pay less attention to context. "The present results provide a useful warning in a world were opportunities to meet people from other cultural backgrounds continue to increase. "People from different cultures may allocate attention differently, even within a shared environment. "The result is that we see different aspects of the world, in different ways." |
| In defence of cynicism By Steve Tomkins I am a cynic. I have a lock on my front door, because I don't trust people not to steal my stuff given the chance. I shop around, because I don't expect shops to sell me CDs at the most reasonable price they can afford. I check up on my children because I know they won't do what they're told if I don't. A friend of mine tells me that people are fundamentally good and honest - but she still keeps a list of everyone she lends a book to, and never fails to check her change. The idea that people are basically motivated by self-interest is not a pleasant one - that advantage goes to my friend's philosophy. But it is true, I think. In years gone by, this was generally accepted, because the church told us that since "the Fall of Man" humans were selfish to the root and needed redemption. Today evolutionary biology repeats the same message, without the remedy. Natural selection favours those who are best at looking after their own interests and those of their offspring. Society has evolved because cooperation and mutual kindness (within limits) benefit the individual better than throwing rocks at everyone. Those who are honest we trust, those who are kindly we like, those who steal lose our respect and their jobs How much of what we call being a good person is actually smart self-interest? I give selflessly to all my friends on their birthdays - and expect them to do exactly the same when mine comes round. Those who are honest we trust, those who are kindly we like, those who steal lose our respect and their jobs. Of course this "the sun shines on the righteous" system has as many loopholes as a fishing net, and that's why most of us get our fair share of sunlight without being shining examples of righteousness. Self interest All the evidence is that we are only as good as it suits us to be. How else can you explain why in 2003 humans beat our previous record high for carbon emissions by 13%, despite the fact that the World Health Organisation says global warming already kills a conservative 150,000 people a year? Why else would a mere 2.4% of UK food and drink spending go on organic produce, and a fraction of even that figure on fair trade goods? How many adverts say "Buy this. It may not be as cool or as efficient as the competition, but you know it's morally right"? Advertisers appeal to our self-interest, because they find that's what gets our wallets out. In 1971, Prof. Philip Zimbardo of Stamford University ran a psychological experiment, which involved groups of "peacenik" student volunteers being put a Big-Brother-house-type prison. They were divided into guards and prisoners, dressed in uniforms and masks and given numbers instead of names. They were left unsupervised and supposedly unobserved. The experiment had to be called off after six days, because the "guards" were physically and mentally assaulting their wards, with midnight strip-searches and toilet cleaning by hand (literally). The moral being, that we aren't moral beings. Take away the advantage in being decent humans, and we aren't. The importance of cynicism is not just that it's true. It's that recognising human selfishness gives us a chance to do something about it. Take away the advantage in being decent humans, and we aren't It is those who do not trust global corporations to protect the interests of their Third-World employees and neighbours who campaign for a fairer world. It is those who do not expect businesses and individuals to be environmentally friendly when left to their own devices who work out incentives and restrictions to cut our reckless pollution. If our society is becoming ever more cynical, then we are less easy prey for the manipulations of advertisers and filmmakers, politicians and media. We listen with sharper ears and read with smarter eyes, which helps us to divide the truth from the propaganda - just so long as we haven't become incapable of believing anything. The First World War was fought with the utter trust and unquestioning support of the British people, and eight and a half million soldiers died in the four years of futile, indefensible butchery. The 2003 Iraq War was fought with less public trust than any other modern war, and about 6,000 combatants have died. Even if there are no winners in war, that arithmetic must in part suggest a small victory for cynicism. Story from BBC NEWS: http://news.bbc.co.uk/go/pr/fr/-/1/hi/magazine/3499307.stm Published: 2004/02/18 11:24:24 GMT |
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NEW YORK POST SHERMER INTERVIEW ON GOOD AND EVIL "BAD TO THE BONE" New York Post, Sunday January 12, 2004 By LOGAN HILL Kobe Bryant cheated on his wife, Vanessa - who followed her more civilized impulses and publicly forgave him. January 11, 2004 -- Britney's quickie Vegas marriage was all anybody was talking about last week. People just couldn't help themselves. As it turns out, that excuse may be exactly right. In his new book, "The Science of Good and Evil: Why People Cheat, Gossip, Care, Share and Follow the Golden Rule" (Times Books, $26), Scientific American columnist and Skeptic Magazine editor Michael Shermer argues that our moral impulses are more a matter of biological hard-wiring than conscious choice. What's more, he says that human beings have stopped evolving morally - and our baser impulses to lie, cheat, gossip and steal are behaviors we'll just have to learn to live with. The author, a self-proclaimed "non-theistic agnostic," uses everything from anthropology to neuroscience and philosophy - but emphatically not religion - to chronicle the evolution of human morality. "Our basic moral principles evolved hundreds of thousands of years ago, before religion came along and encoded them," says Shermer. "People wonder, 'Why should I be moral?' " he says. "In a sense, [they] might as well ask, 'Why should I be in love? Or be hungry?' "It's just basic to human nature." Like the desire for sex or food, "guilt and shame and pride and the sense of justice and injustice" evolved to help the human race survive. But even when we're generous, he says, we're really only interested in what's in it for ourselves. Moral acts of altruism, sympathy or cooperation have historically enabled groups - and the species itself - to prosper. "If everybody in a group did the wrong thing most of the time, these groups would not survive," Shermer explains. "For a social primate species to survive in a fairly harsh world, there must be a level of cooperation." But Shermer holds little hope that human beings will continue to refine their sense of right and wrong - in fact, he thinks that this is as good as society gets. As evidence, he says that several of the same moral qualities found in early human history are still with us today - and they influence everything from how we gossip to why we go to war. So we asked Shermer to explain some specific behavior. For example: Why do we generously tip a waiter we'll never see again? "Fairness is a deep evolutionary feeling that evolved because it's good for the group," Shermer says. Shermer says we have an innate sense of what's fair and what's not, and cites studies done involving both primates and small children. "Young children know whether they're getting a fair [share] or not down to the microscopic difference in the size of slices of birthday cake," Shermer says. "They'll shout, 'I was cheated!' The sense of what's fair and what isn't is deeply ingrained." If we're so inclined to be fair, why would, say, a wealthy man like Sam Waksal break the law just to avoid losing money in the stock market? Shermer says we have an inherent ability to excuse our own immoral desires - to, perhaps, convince ourselves that we "deserve" to break the rules. "We can rationalize all kinds of selfish behaviors," he says, even though we are programmed by culture, history and evolution to resist pursuing our own happiness at the expense of another's. On a grander scale, Shermer says he is not a believer in moral absolutes like good and evil; he believes anything and anyone can be explained, including a terrorist like Osama bin Laden - who Shermer maintains is not pure evil, but a man who, like the rest of us, had potential for both good and evil. The author maintains that environmental conditions informed his decision to choose to commit acts of atrocity. People like bin Laden, says Shermer, somehow "override our evolutionary propensity toward moral behavior and the repulsion most of us would, or at least should, feel." But such extreme acts, he says, are aberrations. Easier to explain, he says, are far more commonplace behaviors like gossip - even about people we don't know, like Ms. Spears and her lamentable ex-husband. We're compelled, he says, to talk about "who's sleeping with who, who's a bully, who's a cooperator, who's not," says Shermer. "It's really important to gossip so you know who's going to [take care of you]," he says. "[Nowadays] we spread a lot of information that's not true, but originally gossip had a good, positive and useful impulse. That's the normal human thing to do - to talk about other people." And when it comes to adultery, the evolutionary benefits are obvious, says Shermer. "For the male, depositing one's genes in more places increases the probability of . . . genetic immortality. For the female, it's a chance to trade up for better genes and higher social status. Still, Shermer holds out a bit of hope that human beings could actually develop even better behavior. "Those guys made a good start of it," he says, referring to the authors of the Bible, Koran and Talmud. "But we live in a completely different world. "It's time," he says, "that we came up with something better." |
| More Than Good Intentions: Holding Fast to
Faith in Free Will New York Times December 31, 2002 JOHN HORGAN When I woke this morning, I stared at the ceiling above my bed and wondered: to what extent will my rising really be an exercise of my free will? Let's say I got up right . . . now. Would my subjective decision be the cause? Or would computations unfolding in a subconscious neural netherworld actually set off the muscular twitches that slide me out of the bed, quietly, so as not to wake my wife, and propel me toward the door? One of the risks of science journalism is that occasionally you encounter research that threatens something you cherish. Free will is something I cherish. I can live with the idea of science killing off God. But free will? That's going too far. And yet a couple of books I've been reading lately have left me brooding over the possibility that free will is as much a myth as divine justice. The chief offender is "The Illusion of Conscious Will," by Dr. Daniel M. Wegner, a psychologist at Harvard. What makes Dr. Wegner's critique more effective than others I've read over the years is that it is less philosophical than empirical, drawing heavily upon recent research in cognitive science and neurology. Dr. Wegner also carries out his vivisection of free will with a disturbing cheerfulness, like a neurosurgeon joking as he cuts a patient's brain. We think of will as a force, but actually, Dr. Wegner says, it is a feeling ‹ "merely a feeling," as he puts it ‹ of control over our actions. I think, "I'm going to get up now," and when I do a moment later, I credit that feeling with having been the instigating cause. But as we all know, correlation does not equal causation. When neurologists make patients' limbs jerk by electrically zapping certain regions of their brains, the patients often insist they meant to move that arm, and they even invent reasons why. Neurologists call these erroneous, post hoc explanations confabulations, but Dr. Wegner prefers the catchier "intention inventions." He suggests that whenever we explain our acts as the outcome of our conscious choice, we are engaging in intention invention, because our actions actually stem from countless causes of which we are completely unaware. He cites experiments in which subjects pushed a button whenever they chose while noting the time of their decision as displayed on a clock. The subjects took 0.2 seconds on average to push the button after they decided to do so. But an electroencephalograph monitoring their brain waves revealed that the subjects' brains generated a spike of brain activity 0.3 seconds before they decided to push the button. The meaning of these widely debated findings, Dr. Wegner says, is that our conscious willing is an afterthought, which "kicks in at some point after the brain has already started preparing for the action." Other research has indicated that the neural circuits underlying our conscious sensations of intention are distinct from the circuits that actually make our muscles move. This disconnect may explain why we so often fail to carry out our most adamant decisions. This morning, I may resolve to drink only one cup of coffee instead of two, or to take a long run through the woods. But I may do neither of these things (and chances are I won't). Sometimes our intentions seem to be self-thwarting. The more I tell myself to go back to sleep instead of obsessing over free will, the wider awake I feel. Dr. Wegner attributes these situations to "ironic processes of mental control." Edgar Allan Poe's phrase "the imp of the perverse" even more vividly evokes that mischievous other we sense lurking within us. Brain disorders can exacerbate experiences of this kind. Schizophrenics perceive their very thoughts as coming from malevolent external sources. Those who have lasting damage to the corpus callosum, a neural cable that transmits signals between the brain's hemispheres, may be afflicted with alien-hand syndrome. They may end up, Dr. Wegner says, like Dr. Strangelove, whose left hand frantically tried to keep his right from jutting out in Nazi salutes. Perfectly healthy people may lose their sense of control over actions their brains have clearly initiated. When we are hypnotized, playing with Ouija boards, or speaking in tongues, we may feel as though someone or something else is acting through us, whether a muse, ghost, devil, or deity. What all these examples imply is that the concept of a unified self, which is a necessary precondition for free will, is itself an illusion. Dr. Wegner quotes Arthur C. Clarke's remark that "any sufficiently advanced technology is indistinguishable from magic." Because we cannot possibly understand how the fantastically complex machines in our skulls really work, Dr. Wegner says, we explain our behavior in terms of such silly, occult concepts as "the self" and "free will." Our belief in our personal identity and self-control does have its uses, Dr. Wegner grants; without it, "we might soon be wearing each other's underclothing." Maybe I should lighten up and embrace my lack of free will and a self. That's what Dr. Susan Blackmore, a British psychologist and a practitioner of Zen, advises. In her book "The Meme Machine," she contends that our minds are really just bundles of memes, the beliefs and habits and predilections that we catch from one another like viruses. Take all of the memes out of a mind, and there is no self left to be free. Once you realize you have no control over your destiny, says Dr. Blackmore, you will expend less energy regretting past decisions and fretting over future ones, and you will be more appreciative of the vital present. Be here now, and so on. In other words, true freedom comes from accepting there is no freedom. Dr. Blackmore's reasoning strikes me as less spiritual than Orwellian. To me, choices, freely made, are what make life meaningful. Moreover, our faith in free will has social value. It provides us with the metaphysical justification for ethics and morality. It forces us to take responsibility for ourselves rather than consigning our fate to our genes or God. Free will works better than any other single criterion for gauging the vitality of a life, or a society. Theologians have proposed that science still allows faith in a "God of the gaps," who dwells within those shadowy realms into which science has not fully penetrated, such as the imaginary time before the Big Bang banged. In the same way, maybe we can have a free will of the gaps. No science is more riddled with gaps, after all, than the science of human consciousness. As I lay in bed this morning, however, my faith in free will wavered. Scanning my mind for something resembling will, I found a welter of roiling thoughts and antithoughts, a few of which transcended virtuality long enough for closer inspection. One thought was that, no matter what my intellect decides, I'm compelled to believe in free will. Abruptly my body, no doubt bored with all this pointless cogitation, slipped out of bed, padded to the door, and closed it behind me. Copyright 2002 The New York Times Company Originally from: http://www.nytimes.com/2002/12/31/science/31ESSA.html |
Hijacking the Brain Circuits With a Nickel Slot Machine New York Times February 19, 2002 By SANDRA BLAKESLEE Compulsive gambling, attendance at sporting events, vulnerability to telephone scams and exuberant investing in the stock market may not seem to have much in common. But neuroscientists have uncovered a common thread. Such behaviors, they say, rely on brain circuits that evolved to help animals assess rewards important to their survival, like food and sex. Researchers have found that those same circuits are used by the human brain to assess social rewards as diverse as investment income and surprise home runs at the bottom of the ninth. And, in a finding that astonishes many people, they found that the brain systems that detect and evaluate such rewards generally operate outside of conscious awareness. In navigating the world and deciding what is rewarding, humans are closer to zombies than sentient beings much of the time. The findings, which are gaining wide adherence among neuroscientists, challenge the notion that people always make conscious choices about what they want and how to obtain it. In fact, the neuroscientists say, much of what happens in the brain goes on outside of conscious awareness. The idea has been around since Freud, said Dr. Gregory Berns, a psychiatrist at Emory University School of Medicine in Atlanta. Psychologists have studied unconscious processing of information in terms of subliminal effects, memory and learning, he said, and they have started to map out what parts of the brain are involved in such processing. But only now are they learning how these different circuits interact, he said. "My hunch is that most decisions are made subconsciously with many gradations of awareness," Dr. Berns said. "For example, I'm vaguely aware of how I got to work this morning. But consciousness seems reserved for more important things." Dr. P. Read Montague, a neuroscientist at Baylor College of Medicine in Houston, says the idea that people can get themselves to work on automatic pilot raises two questions: how does the brain know what it must pay conscious attention to? And how did evolution create a brain that could make such distinctions? The answer emerging from experiments on animals and people is that the brain has evolved to shape itself, starting in infancy, according to what it encounters in the external world. As Dr. Montague explained it, much of the world is predictable: buildings usually stay in one place, gravity makes objects fall, light falling at an oblique angle makes long shadows and so forth. As children grow, their brains build internal models of everything they encounter, gradually learning to identify objects and to predict how they move through space and time. As new information flows into it from the outside world, the brain automatically compares it to what it already knows. If things match up ‹ as when people drive to work every day along the same route ‹ events, objects and the passage of time may not reach conscious awareness. But if there is a surprise ‹ a car suddenly runs a red light ‹ the mismatch between what is expected and what is happening instantly shifts the brain into a new state. A brain circuit involved in decision making is activated, again out of conscious awareness. Drawing on past experience held in memory banks, a decision is made: hit the brake, swerve the wheel or keep going. Only a second or so later, after hands and feet have initiated the chosen action, does the sense of having made a conscious decision arise. Dr. Montague estimates that 90 percent of what people do every day is carried out by this kind of automatic, unconscious system that evolved to help creatures survive. Animals use these circuits to know what to attend to, what to ignore and what is worth learning about. People use them for the same purposes which, as a result of their bigger brains and culture, include listening to music, eating chocolate, assessing beauty, gambling, investing in stocks and experimenting with drugs ‹ all topics that have been studied this past year with brain imaging machines that directly measure the activity of human brain circuits. The two circuits that have been studied most extensively involve how animals and people assess rewards. Both involve a chemical called dopamine. The first circuit, which is in a middle region of the brain, helps animals and people instantly assess rewards or lack of rewards. The circuit was described in greater detail several years ago by Dr. Wolfram Schultz, a neuroscientist at Cambridge University in England, who tracked dopamine production in a monkey's midbrain and experimented with various types of rewards, usually squirts of apple juice that the animal liked. Dr. Schultz found that when the monkey got more juice than it expected, dopamine neurons fired vigorously. When the monkey got an amount of juice that it expected to get, based on previous squirts, dopamine neurons did nothing. And when the monkey expected to get juice but got none, the dopamine neurons decreased their firing rate, as if to signal a lack of reward. Scientists believe that this midbrain dopamine system is constantly making predictions about what to expect in terms of rewards. Learning takes place only when something unexpected happens and dopamine firing rates increase or decrease. When nothing unexpected happens, as when the same amount of delicious apple juice keeps coming, the dopamine system is quiet. In animals, Dr. Montague said, these midbrain dopamine signals are sent directly to brain areas that initiate movements and behavior. These brain areas figure out how to get more apple juice or sit back and do nothing. In humans, though, the dopamine signal is also sent to a higher brain region called the frontal cortex for more elaborate processing. Dr. Jonathan Cohen, a neuroscientist at Princeton, studies a part of the frontal cortex called the anterior cingulate, located in back of the forehead. This part of the brain has several functions, Dr. Cohen said, including the task of detecting errors and conflict in the flow of information being processed automatically. Brain imaging experiments are beginning to show that when a person gets an unexpected reward ‹ the equivalent of a huge shot of delicious apple juice ‹ more dopamine reaches the anterior cingulate. When a person expects a reward and does not get it, less dopamine reaches the region. And when a person expects a reward and gets it, the anterior cingulate is silent. When people expect a reward and do not receive it, their brains need a way to register the fact that something is amiss so it can recalibrate expectations for future events, Dr. Cohen said. As in monkeys, human dopamine neurons project to areas that plan and control movements, he said. Fluctuating levels of dopamine make people get up and do things, outside their conscious awareness. The number of things people do to increase their dopamine firing rates is unlimited, neuroscientists are discovering. Several studies were published last year looking at monetary rewards and dopamine. Money is abstract but to the brain it looks like cocaine, food, sex or anything a person expects is rewarding, said Dr. Hans Breiter, a neuroscientist at Harvard. People crave it. Some people seem to be born with vulnerable dopamine systems that get hijacked by social rewards. The same neural circuitry involved in the highs and lows of abusing drugs is activated by winning or losing money, anticipating a good meal or seeking beautiful faces to look at, Dr. Breiter said. For example, dopamine circuits are activated by cocaine; people become addicted when their reward circuits have been hijacked by the drug, Dr. Montague said. Winning in gambling can also hijack the dopamine system, Dr. Berns said. Many people visit a casino, lose money and are not tempted to go back. But compulsive gamblers seem to have vulnerable dopamine systems, he said. The first time they win, they get a huge dopamine rush that gets embedded in their memory. They keep gambling and the occasional dopamine rush of winning overrides their conscious knowledge that they will lose in the long run. Other experiments show that reward circuits are activated when young men look at photos of beautiful women and that these circuits are defective in women with eating disorders like bulimia. Bulimics say they are addicted to vomiting because it gives them a warm, positive feeling. Music activates neural systems of reward and emotion. Older people with age-related impairments to the frontal cortex do poorly on gambling tasks and, experiments show, are prone to believe misleading advertising. Neuroscientists say that part of the appeal of live sporting events is their inherent unpredictability. When a baseball player with two outs at the bottom of the ninth inning hits a home run to win the game, thousands of spectators simultaneously experience a huge surge of dopamine. People keep coming back, as if addicted to the euphoria of experiencing unexpected rewards. One of the most promising areas for looking at unconscious reward circuits in human behavior concerns the stock market, Dr. Montague said. Economists do not study people, they study collective neural systems in people who form mass expectations. For example, when the Federal Reserve unexpectedly lowered interest rates twice last year, the market went up, he said. When it lowered interest rates on other occasions and investors knew the move was coming, markets did not respond. Economists and neuroscientists use the same mathematical equations for modeling market behavior and dopamine behavior, Dr. Montague said. Neuroscience may provide an entirely new set of constructs for understanding economic decision making. Copyright 2002 The New York Times Company Originally from: www.nytimes.com/2002/02/19/health/19REWA.html?rd=hcmcp?p=042OHR042OId4ANTa012000mq3$vq3yg |