By KAREN BARROW A soldier returns from war unable to get the images of battle out of his head. An earthquake survivor rides out long, anxiety-filled nights. A young woman in a pretty floral dress walks her dog along the streets of Manhattan. All three may be suffering from post-traumatic stress disorder. The woman walking her dog is Robin Hutchins, 25. She looks confident and self-assured, and few would guess that a year ago she discovered that she had the stress disorder. “When I tell people I have P.T.S.D., it’s like I have to convince them it’s a real issue,” she said. The disorder — in which a traumatic experience leaves the patient suffering from severe anxiety for months or years after the event — is often associated with battlefield combat and natural disasters. But as Dr. Frank Ochberg, a clinical professor of psychiatry at Michigan State University, noted in an interview, the typical trigger is more mundane — most commonly, a traffic accident. In Ms. Hutchins’s case, it was sexual violence. During her first year in college, on a weekend home to tend to a broken leg, she was raped by a young man she knew. She returned to college without telling her parents about it. “I just really wanted to be a freshman in college,” she said. Ms. Hutchins spoke to a counselor there and resumed her routine — attending class, hanging out with friends and trying to put the trauma behind her. “Nobody ever said, ‘You need to stop your life and deal with this — you can’t just walk through it,’ ” she said. Copyright 2010 The New York Times Company

Keyword: Stress; Depression
Link ID: 14704 - Posted: 11.23.2010

By SINDYA N. BHANOO The human tendency to form close bonds with people other than kin may have primal roots. Researchers from Germany report in the journal Current Biology that male macaques exhibit a social bonding behavior similar to human friendship. A macaque in Thailand. Scientists say males of the species develop bonds like human friendship. Macaque monkeys live in groups of 50 to 60, but “every male in the group has a few other males he interacts with more than others,” said Oliver Schülke, the study’s lead author and an evolutionary biologist at the University of Göttingen. Dr. Schülke and his colleagues studied male Assamese macaques in Thailand over a period of five years and monitored their behavior. Macaques that spent a lot of time within 1.5 meters of each other were considered friends, since it is easy to attack another macaque at this distance. Males that groomed each other’s bodies frequently and for excessive periods of time were also considered friends. Often, they groomed areas that an individual could groom himself. “The grooming seems to work to foster these bonds,” Dr. Schülke said. “The hygiene aspect was only one part of it.” The bonds can lead to the forming of coalitions, where a group of males might fight another male to improve rank and social status, the researchers found. Copyright 2010 The New York Times Company

Keyword: Aggression; Sexual Behavior
Link ID: 14703 - Posted: 11.23.2010

by Nathan Collins Add this to your list of worries, high schoolers: daylight savings time might mess with your college admissions. For decades, scientists have debated whether spring and fall time changes affect everything from seasonal affective disorder to traffic accidents. The idea is that resetting clocks by "springing forward" and "falling back" can upset sleep patterns and with them the ability to concentrate. Now, it appears that these time changes might just muck up performance on the SAT, the U.S. college admissions exam, which is administered five times a year, including two dates that fall after daylight savings transitions. Using data from Indiana, where until recently individual counties could opt in or out of daylight savings, researchers found that scores in counties that changed their clocks were consistently 16.34 points—or 2%—lower than in counties that did not, they report online this month in the Journal of Neuroscience, Psychology, and Economics. That may not sound like a lot, but it may be enough to keep you out of Harvard. So choose your test dates carefully, kids. Springing forward could land you in your fall-back school. © 2010 American Association for the Advancement of Science.

Keyword: Biological Rhythms; Attention
Link ID: 14702 - Posted: 11.23.2010

MAGIC, it mystifies and captivates us. We shake our heads in disbelief as coins are conjured out of thin air, as cards are mysteriously summoned from a pack, and as the magician's assistant vanishes before our eyes. Of course, there is no such thing as "magic", so how does magic work? It's a question that neuroscientists like Stephen Macknik and Susana Martinez-Conde are trying to answer. In the process they have conjured up a new branch of cognitive research called neuromagic. From misdirection and the magical practice of "forcing", to mirror neurons and synaptic plasticity, Sleights of Mind is a spellbinding mix of magic and science. The authors invite us to sip this heady potion as they show us how understanding the myriad ways in which the brain is deceived by magic may solve some of the mysteries surrounding how it works. "Magic tricks fool us because humans have hard-wired processes of attention and awareness that are hackable," say the authors. Magicians use your mind's intrinsic properties against you. In a magical feat of their own, the authors persuaded magicians such as James Randi and Teller from the Las Vegas headline act Penn and Teller to deconstruct tricks so that Macknik and Martinez-Conde could later attempt to reconstruct what is going on inside your head "as you are suckered". Magic, say the neuroscientists, could reveal how the brain functions in everyday situations such as shopping. However, it is a stretch to believe, as the authors do, that if you've bought an expensive item you never intended to buy, then you were probably a victim of the "illusion of choice", a technique magicians use to rob their dupes of genuine choice. © Copyright Reed Business Information Ltd.

Keyword: Attention
Link ID: 14701 - Posted: 11.23.2010

By FRED VOGELSTEIN Once every three or four months my son, Sam, grabs a cookie or a piece of candy and, wide-eyed, holds it inches from his mouth, ready to devour it. He knows he’s not allowed to eat these things, but like any 9-year-old, he hopes that somehow, this once, my wife, Evelyn, or I will make an exception. We never make exceptions when it comes to Sam and food, though, which means that when temptation takes hold of Sam and he is denied, things can get pretty hairy. Confronted with a gingerbread house at a friend’s party last December, he went scorched earth, grabbing parts of the structure and smashing it to bits. Reason rarely works. Usually one of us has to pry the food out of his hands. Sometimes he ends up in tears. It’s not just cookies and candy that we forbid Sam to eat. Cake, ice cream, pizza, tortilla chips and soda aren’t allowed, either. Macaroni and cheese used to be his favorite food, but he told Evelyn the other day that he couldn’t remember what it tastes like anymore. At Halloween we let him collect candy, but he trades it in for a present. At birthday parties and play dates, he brings a lunchbox to eat from. There is no crusade against unhealthful food in our house. Some might argue that unhealthful food is all we let Sam eat. His breakfast eggs are mixed with heavy cream and served with bacon. A typical lunch is full-fat Greek yogurt mixed with coconut oil. Dinner is hot dogs, bacon, macadamia nuts and cheese. We figure that in an average week, Sam consumes a quart and a third of heavy cream, nearly a stick and a half of butter, 13 teaspoons of coconut oil, 20 slices of bacon and 9 eggs. Sam’s diet is just shy of 90 percent fat. Copyright 2010 The New York Times Company

Keyword: Epilepsy; Obesity
Link ID: 14700 - Posted: 11.23.2010

By Steve Connor, Science Editor Blind patients suffering from a type of eye disease that strikes in childhood will become the second group of people in the world to receive stem cells derived from spare IVF embryos left over from fertility treatment. The US Food and Drug Administration (FDA) has given the go-ahead for the controversial transplant of embryonic stem cells into the eyes of patients with Stargardt's macular degeneration, where the light-sensitive retina cells at the back of eye are destroyed. The announcement follows the first injection of embryonic stem cells into a patient in the US who is partially paralysed as a result of a spinal cord injury. Last October, a US biotechnology company, Geron, announced the start of the first clinical trial of embryonic stem cells with the hope of repairing damaged nerves. Another US biotechnology firm, Advanced Cell Technology, has now been given approval for a second clinical trial involving the injection of thousands of embryonic stem cells into the eyes of a dozen adult patients with a juvenile form of macular degeneration. Robert Lanza, the company's chief scientific officer, said that the first patient could receive the stem cell transplants early in the new year and although the trial is designed primarily to assess safety, the first signs of visual improvement may be apparent within weeks. "Talking to the clinicians, we could see something in six weeks, that's when we think we may see some improvements. It really depends on individual patients but that's a reasonable time frame when something may start to happen," Dr Lanza said. ©independent.co.uk

Keyword: Stem Cells; Vision
Link ID: 14699 - Posted: 11.22.2010

By ANDREW POLLACK LOS ANGELES — Elderly people losing their vision from age-related macular degeneration might one day have a treatment option that requires fewer injections into the eye than the standard drug now used. In testing, an experimental drug being developed by Regeneron Pharmaceuticals, when injected every eight weeks, proved as effective as the standard treatment, Lucentis from Genentech, which was injected every four weeks. The findings are from two clinical trials that Regeneron is expected to announce on Monday. In a separate development, Advanced Cell Technology is expected to announce Monday that it has won regulatory approval to test a therapy derived from human embryonic stem cells in people with Stargardt’s macular dystrophy, another retina disease. It is only the second trial of a therapy derived from human embryonic stem cells to be cleared by the Food and Drug Administration. The first involves a treatment for spinal cord injury developed by Geron. Age-related macular degeneration is the leading cause of blindness in the elderly. Lucentis can restore a person’s ability to drive and read, in some cases. But the drug works best when given every four weeks, which can be inconvenient for patients and doctors. Doctors often give Lucentis less frequently, but even if that regimen produces good results, patients must still get checkups every month to make sure their vision is not deteriorating. Regeneron’s drug, which is called VEGF Trap-Eye, “gives us the opportunity to not have to see them monthly,” said Dr. Jeffrey Heier of Boston, an investigator in one of the trials and a consultant to Regeneron. That would be “very meaningful to patients and their families,” he said. Copyright 2010 The New York Times Company

Keyword: Vision; Stem Cells
Link ID: 14698 - Posted: 11.22.2010

by Andy Coghlan NERVE cells with huge potential for treating paralysis could be made from a person's own skin or hair follicles, making spinal repair a more realistic prospect. Studies in rats and dogs have already demonstrated that olfactory ensheathing cells (OECs), which insulate bundles of nerve cells, can help repair damage to the spinal cord and nerves leading to animals' paws. In rats and dogs, these cells can repair damage to the spinal cord and nerves leading to animals' paws The prospects for using them in treatments have been limited, however, because their only sources were thought to be the lining of the nose and the olfactory bulb in the brain where smell signals are processed. Biopsies from the human nose lining have only yielded tiny numbers of OECs, and obtaining them from the olfactory bulb would be invasive and potentially dangerous. Clare Baker of the University of Cambridge and colleagues injected chicken and mice embryos with neural crest cells genetically engineered to glow green under ultraviolet light. Neural crest cells are primordial cells that have the potential to develop into nervous system cells, among others. By visually tracking the cells in the growing embryos, they found some became OECs (Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.1012248107). Because neural crest cells can also be isolated from skin and hair follicles, OECs could potentially be grown from a patient's own cells. © Copyright Reed Business Information Ltd.

Keyword: Regeneration; Stem Cells
Link ID: 14697 - Posted: 11.22.2010

by Jocelyn Kaiser Tumors are notoriously hard to kill. Attack them with chemotherapy, and they develop drug resistance; surgically remove them, and they may have already metastasized to other parts of the body. Now scientists have found that tumors have yet another trick up their sleeve: They can create their own blood supply by morphing into blood vessels. The observations, reported by two separate teams online today in Nature, could explain why drugs designed to choke off blood to brain tumors often fail. The researchers drew the link between tumor cells and blood vessel cells with a series of experiments on glioblastomas—fast-growing brain tumors that contain tufts of thin, abnormal blood vessels. Neurosurgeon and stem cell scientist Viviane Tabar and colleagues at Memorial Sloan-Kettering Cancer Center in New York City first took glioma samples from the operating room and looked for chromosomal abnormalities in the endothelial cells lining the tumor's blood vessels. They found patterns exactly like those in cells from the tumor itself, suggesting that at least some of the blood vessel cells came from the tumor. The researchers then sorted glioma cells into different types using antibodies that stick to specific proteins on a cell's surface. They showed that the cells that give rise to blood vessels are an immature cancer cell, known as a stemlike cancer cell. Finally, the researchers injected these cancer stem cells into the brains of mice with weakened immune systems and then examined the blood vessels within the resulting tumors. The vessels stained positive for antibodies to human endothelial cells, again showing that some of the cells had to come from the tumor. © 2010 American Association for the Advancement of Science.

Keyword: Glia
Link ID: 14696 - Posted: 11.22.2010

By Courtney Humphries Two years ago, George Winslow’s world was literally thrown off balance. He was working on cars at the auto repair shop he owns in Foxborough when he began to sweat, and every step felt like a struggle. The world began to spin violently. Unable to get his balance, Winslow slammed to the floor. He lost hearing in one ear. He left the shop in an ambulance, and the world didn’t stop moving for more than four grueling hours. Winslow was diagnosed with Meniere’s disease, a progressive disorder of the inner ear that brings severe, unexpected attacks of vertigo, often accompanied by hearing loss, ringing in the ears, and nausea. From then on, Winslow suffered from frequent attacks of intense dizziness, sometimes three or four a week. An active person who had always preferred to work under the hood rather than behind a desk, he was often exhausted and relying more on the help of his staff. “This is the toughest thing I’ve ever gone through,’’ says Winslow, 54. Because a balance disorder is a complex problem to diagnose, people who suffer them often go from doctor to doctor until, like Winslow, they find specialists who can properly treat the problem. After his local doctor offered little help, Winslow eventually found his way to Dr. Steven Rauch, an otologist at the Massachusetts Eye and Ear Infirmary who specializes in treating balance disorders like Meniere’s. Winslow has undergone a series of treatments that have lessened the frequency and duration of the attacks, and he had minor surgery last week that he hopes will further improve the situation. But although his condition has improved, he’s had to adjust to a life out of balance. © 2010 NY Times Co

Keyword: Miscellaneous
Link ID: 14695 - Posted: 11.22.2010

By Steve Connor, Science Editor The elaborate songs of a bird species famed for its wide repertoire of tunes have been decoded for the first time. Scientists have been able to predict the correct sequence of notes and "syllables" in the Bengalese finch's melodious, but erratic songs. The team from Pennsylvania State University now believe they can reproduce the bird's song after studying more than 25,000 melodies recorded from a finch which was kept in a sound-proofed studio on campus for several days. The study, carried out by Dr Dezhe Jin is part of a wider investigation into how individual brain cells can control birdsong, which could help to shed light on the complex neural networks involved in human speech. Earlier work by Dr Jin and his colleagues focused on the simpler songs of the zebra finch – a close relative of the Bengalese version – which has helped to explain how the brain of the bird controlled the complex vocalisation involved when young birds learn to sing the song of their parents. "Unlike dogs and cats, whose vocalisations are innate and unlearned, songbirds learn a song in much the same way as humans learn a language – through cultural transmission," said Dr Jin. ©independent.co.uk

Keyword: Sexual Behavior; Animal Communication
Link ID: 14694 - Posted: 11.20.2010

By Steve Jones Now and again I have a vision. Not of a golden future in which servile oiks queue to put pound coins in a tin before each lecture, nor of a dystopia in which higher education is brought to its knees by a reckless ideological experiment, but of an imaginary cosmos inside my head which projects itself unpredictably upon the real world. The 12th-century mystic and composer Hildegard of Bingen had the same problem: "I saw a great star most splendid and beautiful, and with it an exceeding multitude of falling stars… and suddenly they were all annihilated, being turned to black coals… and cast into the abyss." Almost certainly, she and I had the same condition. My own migraines are restricted to a brief scotoma, a bright but painless pulsing and spinning, circular zigzag that blacks out part of the visual field, while hers – and those of most of the one in 10 of us who experience them – were much more striking. Often the imagined pulse is accompanied by a headache, by vomiting, or by hallucinations of touch, sound, taste or smell. Some people perceive that they are falling, or that their limbs are ballooning or getting smaller. Lewis Carroll is thought to have had the condition, which might have given him the idea for Alice's shrinking when she fell down the rabbit hole and for her massive growth later on. © Copyright of Telegraph Media Group Limited 2010

Keyword: Vision; Pain & Touch
Link ID: 14693 - Posted: 11.20.2010

by Greg Miller Elephants are famous for having a good memory, but they also have complex communication skills and rich social lives. Unfortunately, scientists know virtually nothing about the 5-kilogram brain responsible for these talents. This week, in a presentation at the annual meeting of the Society for Neuroscience and in a paper in Brain Structure and Function, scientists present the first microscopic study of neurons in the cerebral cortex of the African elephant. The cortex is the thin layer of cells on the surface of the brain that governs many functions, and in elephants it contains a greater variety of cell types (such as the extensively branched neuron pictured above) than is found in more frequently studied animals such as rodents and primates. How this complexity contributes to an elephant's smarts isn't known, but the authors say their findings suggest that evolution has found multiple ways to build a complex brain—and an intelligent beast. © 2010 American Association for the Advancement of Science.

Keyword: Evolution
Link ID: 14692 - Posted: 11.20.2010

By Janet Raloff Baby fat can be a harbinger of serious disease later on. Being overweight as a young child is a strong predictor of diabetes and heart disease risk in early adulthood, a new Dutch study finds. Previous research has linked being overweight in childhood with a higher risk of these chronic diseases in adulthood, but the new study is the first to identify the ages between 2 and 6 years as the most important in predicting later risk of metabolic syndrome, says the study’s lead author, physician Marlou de Kroon of Vrije University in Amsterdam. The condition is associated with increased risk of type 2 diabetes and cardiovascular diseases. The new work “is very interesting,” says cardiologist Gerald Berenson, because it reveals the earliest and most critical age for predicting adult weight problems and risk of serious chronic disease. Berenson, who was not involved in the new study, is director of Tulane University’s Center for Cardiovascular Health in New Orleans. In the face of a growing epidemic of childhood obesity, these data are very disturbing, Berenson says. People often disregard children’s weight problems, rationalizing “that kids will grow out of it during puberty,” he says. But the new study shows that the kids may not — and if they don’t, big problems could ensue. To explore the relationship between early weight gain and later disease risk, researchers repeatedly measured the height and weight of 642 Dutch children born between 1977 and 1986 in Terneuzen, the Netherlands. © Society for Science & the Public 2000 - 2010

Keyword: Obesity; Development of the Brain
Link ID: 14691 - Posted: 11.20.2010

Eliza Strickland; How do you track a thought, diagram an emotion, sketch the path of a memory? For as long as humans have tried to understand the mind, we've grappled with such questions. Now in a remarkable new book from Abrams, author Carl Schoonover showcases our species' tenacious attempts to make images of the brain in order to understand ourselves. The image-rich book, titled Portraits of the Mind: Visualizing the Brain From Antiquity to the 21st Century, shows the beautiful results of that quest. "Prod the delicate matter in the head in the appropriate manner, and it just might reveal a small but important flash of insight, a clue among countless other clues," Schoonover writes in the preface. "Prod by prod, glimpse by glimpse, we can begin to form theories about brain structure and function; thus, the history of neuroscience is the history of the techniques we employ to delve into the brain." The book ranges from the earliest cell-staining techniques to the high-tech methods that yield today's "brainbows" and intricate maps of neural architecture. Here we present a sampling of our favorite portraits. © 2010, Kalmbach Publishing Co.

Keyword: Development of the Brain
Link ID: 14690 - Posted: 11.20.2010

by Carl Zimmer Pop quiz: What is 357 times 289? No pencils allowed. No calculators. Just use your brain. Got an answer yet? Got it now? How about now? Chances are you still don’t. As you solved the problem one step at a time, you lost track of the numbers. Maybe you tried to start over, lost track again, and eventually gave up in frustration before you could discover that the answer was 103,173. I used a calculator to get that, I confess. Our mutual failure is absurd. The brain is, in the words of neuroscientist Floyd Bloom, “the most complex structure that exists in the universe.” Its trillions of connections let it carry out all sorts of sophisticated computations in very little time. You can scan a crowded lobby and pick out a familiar face in a fraction of a second, a task that pushes even today’s best computers to their limit. Yet multiplying 357 by 289, a task that demands a puny amount of processing, leaves most of us struggling. For psychologists, this kind of mental shortcoming is like a crack in a wall. They can insert a scientific crowbar and start to pry open the hidden life of the mind. The fact that we struggle with certain simple tasks speaks volumes about how we are wired. It turns out the evolution of our complex brain has come at a price: Sometimes we end up with a mental traffic jam in there. © 2010, Kalmbach Publishing Co.

Keyword: Attention
Link ID: 14689 - Posted: 11.20.2010

Catherine de Lange, The McGurk effect is an auditory illusion. It occurs when a video of a person speaking is given different audio, so the picture and the sounds don't match. Most people will hear a third sound - neither the original audio nor the audio they've just heard (see video above). The illusion demonstrates that we rely on both auditory and visual cues to process speech correctly. Michael Beauchamp and colleagues from the University of Texas in Houston wanted to find out exactly where, and at what point during the perception process, these two senses combine in the brain. Previous studies have pointed to a brain area called the superior temporal sulcus (STS), although some researchers disagree. Now this debate can be laid to rest. Part of the problem is that the STS region for auditory-visual integration is located at a different spot in each person, says Beauchamp. He therefore began by conducting MRI scans to determine its exact location in the brain of each subject. Next, a technique called transcranial magnetic stimulation (TMS) was applied to find out whether the STS really is responsible for the McGurk effect. TMS fires a series of short electromagnetic pulses at a target area of the brain to deactivate it, so if the STS was the key, subjects undergoing TMS to that area wouldn't perceive the illusion. © Copyright Reed Business Information Ltd.

Keyword: Hearing; Language
Link ID: 14688 - Posted: 11.17.2010

By JR Minkel Could some cases of schizophrenia boil down to something as simple as vitamin D deficiency? The idea was first put forth more than a decade ago by schizophrenia researcher John McGrath of the University of Queensland in Australia. The circumstantial evidence fit: people born in winter or spring or at high latitudes are at slightly increased risk of developing schizophrenia, and vitamin D deficiency is also more common in winter months and at high latitudes because of lack of sunlight. It may be that a deficit of vitamin D leaves expecting mothers more vulnerable to illnesses such as influenza, which could in turn sensitize the maturing brain to stress-related damage later in life. [For more on how prenatal infections can lead to mental illness, see “Infected with Insanity,” by Melinda Wenner; Scientific American Mind, April/May 2008.] Now McGrath and his colleagues have put the hypothesis to the test. They analyzed blood samples taken from 424 Danish newborns who went on to develop schizophrenia as well as an equal number of babies who never acquired the disease. In each sample, they measured the amount of the chemical 25OHD, which the body converts into vitamin D. The researchers found that infants who had low levels of 25OHD in their blood—and therefore mothers who were deficient in vitamin D while they were pregnant—were at a higher risk of developing schizophrenia when they grew up. The result, published in the September issue of Archives of General Psychiatry, could be especially interesting for communities of black immigrants living in northern countries. Researchers have found a striking increase in schizo­phrenia risk for the children of dark-skinned migrants living at high latitudes—a finding neatly explained if vitamin D plays a role, because dark skin blocks ultraviolet B radiation, the component of sunlight necessary for the body to synthesize vitamin D. © 2010 Scientific American

Keyword: Schizophrenia; Development of the Brain
Link ID: 14687 - Posted: 11.17.2010

By Laura Sanders SAN DIEGO — In the two-hour window after a stroke, flicking a single whisker completely prevents many damaging effects in a rat, a new study finds. The cheap, simple intervention, described November 15 at a news conference at the annual Society for Neuroscience meeting, may represent a new way to minimize disability after a stroke. “I think it’s one of the most profound findings that have come along in recent years,” said neuroscientist Carol Barnes of the University of Arizona in Tucson. “There is no brain damage. It’s almost a miracle. It’s almost too good to be true. Any protection would be good, but this is more than dramatic.” Researchers led by Ron Frostig of the University of California, Irvine mimicked a stroke by severing a major blood vessel in rats’ brains. Then at times during the two hours immediately afterward, a mechanical rod stimulated a single whisker on the anesthetized rat for a total of less than five minutes. With whisker stimulation, the team saw that blood began to flow backward through the severed vessel and got rerouted through other vessels, ultimately reaching the brain area that would have been deprived of blood. No such rerouting was present in rats that didn’t have a whisker stimulated, or in rats that had whisker stimulation more than two hours after the stroke. The team’s preliminary data suggest that the method works for conscious rats, too. © Society for Science & the Public 2000 - 2010

Keyword: Stroke
Link ID: 14686 - Posted: 11.17.2010

WHAT makes people psychopaths is not an idle question. Prisons are packed with them. So, according to some, are boardrooms. The combination of a propensity for impulsive risk-taking with a lack of guilt and shame (the two main characteristics of psychopathy) may lead, according to circumstances, to a criminal career or a business one. That has provoked a debate about whether the phenomenon is an aberration, or whether natural selection favours it, at least when it is rare in a population. The boardroom, after all, is a desirable place to be—and before the invention of prisons, even crime might often have paid. To shed some light on this question Elsa Ermer and Kent Kiehl of the University of New Mexico, Albuquerque, decided to probe psychopaths’ moral sensibilities and their attitude to risk a little further. Their results do not prove that psychopathy is adaptive, but they do suggest that it depends on specific mechanisms (or, rather, a specific lack of them). Such specificity is often the result of evolution. Past work has established that psychopaths have normal levels of intelligence (they are only rarely Hannibal Lecter-like geniuses). Nor does their lack of guilt and shame seem to spring from a deficient grasp of right and wrong. Ask a psychopath what he is supposed to do in a particular situation, and he can usually give you what non-psychopaths would regard as the correct answer. It is just that he does not seem bound to act on that knowledge. © The Economist Newspaper Limited 2010.

Keyword: Aggression; Emotions
Link ID: 14685 - Posted: 11.16.2010