Chapter 1. An Introduction to Brain and Behavior

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By AMANDA SCHAFFER For years, researchers have investigated how the body loses the ability to produce enough insulin, a hallmark of diabetes. Now an intriguing theory is emerging, and it suggests a potential treatment that few scientists had considered. The hormone insulin helps shuttle glucose, or blood sugar, from the bloodstream into individual cells to be used as energy. But the body can become resistant to insulin, and the beta cells of the pancreas, which produce the hormone, must work harder to compensate. Eventually, the thinking goes, they lose the ability to keep up. “We used to say that the beta cells poop out,” said Alan Saltiel, director of the Life Sciences Institute at the University of Michigan. In reality, he added, this shorthand meant “we have no idea what’s going on.” Some evidence suggested that large numbers of these cells died through a process of programmed cell death called apoptosis. But that was at best a partial explanation. Now, researchers at Columbia University have put forth a surprising alternative. In mice with Type 2 diabetes, the researchers showed that beta cells that had lost function were not dead at all. Most remained alive, but in a changed form. They reverted to an earlier developmental, “progenitor,” state. It’s as if these cells are “stepping back in time to a point where they look like they might have looked during their development,” said Dr. Domenico Accili, director of the Columbia University Diabetes and Endocrinology Research Center, who led the new work. © 2012 The New York Times Company

Keyword: Stress; Aggression
Link ID: 17321 - Posted: 10.02.2012

By Gregory Thomas, During an introductory psychology course at Britain’s University of Essex in 2009, Arnold Wilkins asked his class to participate in a quick experiment. Wilkins projected two images on a wall and asked students to write down whether they found either of them disturbing. One was a photograph of a woody landscape. The other was a close-up of a lotus-flower seedpod — a flat-faced pod pocked with small holes. Most of the students were unmoved, but one, freshman An Le, recalls being both transfixed and revolted by the lotus image. “It felt like I was in shock,” he says. Le is far from alone in his response. Thousands of people claim to suffer trypophobia, a term derived from the Greek “trypo,” which means punching, drilling or boring holes. It refers to an irrational fear of clusters of small holes, such as beehives, ant holes and even bubbles in a pancake on the griddle or air pockets in a chocolate bar. On Web sites and blogs, self-diagnosed trypophobes share tales of vomiting, sleep loss and anxiety attacks at the sight of such objects as honeycombs and rotting wood. They say the fears are haunting and disruptive of their daily lives. But the medical world hasn’t yet embraced the phobia as real. Trypophobia isn’t listed in any major dictionary or in the Diagnostic and Statistical Manual of Mental Disorders. Attempts to add trypophobia to the Oxford English Dictionary and even to establish a Wikipedia page have been rebuffed because there hasn’t been any research published on the subject. A Wikipedia editor who deleted an entry on trypophobia in 2009 noted that trypophobia is “likely hoax and borderline patent nonsense.” © 1996-2012 The Washington Post

Keyword: Emotions; Aggression
Link ID: 17320 - Posted: 10.02.2012

By BENEDICT CAREY Proposed changes to the official diagnosis of autism will not reduce the proportion of children found to have it as steeply as many have feared, scientists reported on Tuesday, in an analysis that contradicts several previous studies. Earlier research had estimated that 45 percent or more of children currently on the “autism spectrum” would not qualify under a new definition now being refined by psychiatric researchers — a finding that generated widespread anxiety among parents who rely on state-financed services for their children. The new report, posted online Tuesday by The American Journal of Psychiatry, concluded that the number who would be excluded is closer to 10 percent. The finding may soothe the anxieties of some parents, but will not likely settle the debate over the effect of the new diagnosis. All sides agree that the proposed criteria are narrower and will likely result in fewer diagnoses of autism, but until doctors begin using the new definition widely, the predictions of its effect are just that: predictions. The debate has simmered over the past year as an expert panel appointed by the American Psychiatric Association has updated its proposals for the association’s Diagnostic and Statistical Manual of Mental Disorders, scheduled to take effect in May 2013. The manual is the field’s standard reference, and several recent studies suggested that the amended autism definition was far narrower than intended. © 2012 The New York Times Company

Keyword: Autism
Link ID: 17319 - Posted: 10.02.2012

By Simon J Makin Humans are born to a longer period of total dependence than any other animal we know of, and we also know that mistreatment or neglect during this time often leads to social, emotional, cognitive and mental health problems in later life. It’s not hard to imagine how a lack of proper stimulation in our earliest years – everything from rich sensory experiences and language exposure to love and care – might adversely affect our development, but scientists have only recently started to pull back the curtain on the genetic, molecular and cellular mechanisms that might explain how these effects arise in the brain. You’ll often hear it said that human beings are “social animals”. What biologists tend to mean by that phrase is behaviour like long-lasting relationships or some kind society, whether that’s the social hierarchy of gorillas or the extreme organisation of bees and ants. But, to an extent, most animals are social. A mother usually bonds with its offspring in any species of bird or mammal you care to mention, and almost all animals indulge in some kind of social behaviour when they mate. But there is another sense in which most animals seem to be fundamentally social. There is an emerging scientific understanding of the way social experience moulds the biochemistry of the brain and it looks like most species don’t just prefer the company of others – they need it to develop properly. Take that staple of genetics research, drosophila – aka the fruit fly. While they are not as social as primates or bees, they are more social than you might think, and there have been studies showing that social isolation can disrupt their mating behaviour or even reduce their lifespan. © 2012 Scientific American,

Keyword: Development of the Brain; Aggression
Link ID: 17318 - Posted: 10.02.2012

By NICHOLAS BAKALAR A small study has found that obese children are more likely than others to have a weak sense of taste. German researchers tested tasting ability in 99 obese and 94 normal-weight children, whose average age was 13, by having them try to identify tastes on strips of filter paper and asking them to distinguish among sweet, sour, salty, umami (savory) and bitter. The children also were asked to rate the taste’s intensity on a five-point scale. Girls were better than boys at distinguishing tastes, and older children scored higher than younger; there were no differences by ethnicity. Obese children scored an average of 12.6 out of a possible 20, while the normal-weight children averaged 14.1, a statistically significant difference. On the intensity scale, obese children rated all flavor concentrations lower than did those in the normal-weight group. “We think it’s important, especially for young children, to get different tastes so that they can improve their taste sensitivity,” said the lead author, Dr. Johanna Overberg, a pediatrician at Charité Children’s Hospital in Berlin. “If you taste more and different things at younger ages, you can do this.” The authors, writing online in the Archives of Disease in Childhood, say the reason for the association is unclear, but they suggest that the hormone leptin may affect both body weight and the sensitivity of taste buds. Copyright 2012 The New York Times Company

Keyword: Obesity; Aggression
Link ID: 17317 - Posted: 10.02.2012

by Jessica Hamzelou California has become the first US state to ban unfounded therapies that attempt to turn gay teenagers straight. "These practices have no basis in science or medicine and they will now be relegated to the dustbin of quackery," said state governor Jerry Brown in a statement to the San Francisco Chronicle. He signed a bill outlawing the therapies on 29 September. Brown's conclusions are in line with those reached a few years ago by a task force of psychologists who were commissioned by the American Psychological Association to assess all published research on the therapies. The group, led by Judith Glassgold, found no evidence that the treatment was effective. "The scientific evidence does not support such therapies," says Clinton Anderson, director of the APA's Lesbian, Gay, Bisexual and Transgender Concerns office. "They were not helpful and could be harmful," says Glassgold, who is based in Washington DC. "Most people became more depressed and anxious, and could become suicidal." "Usually these talk therapies are based on the assumption that homosexuality is a mental illness caused by poor parenting and confused gender roles," she adds. "They attempt to explain that to the patient, and try to get them to act and behave in a heterosexual manner." © Copyright Reed Business Information Ltd

Keyword: Sexual Behavior
Link ID: 17316 - Posted: 10.02.2012

By Tori Rodriguez A common complaint about wrinkle-masking Botox is that recipients have difficulty displaying emotions on their faces. That side effect might be a good thing, however, for people with treatment-resistant depression. In the first randomized, controlled study on the effect of botulinum toxin—known commercially as Botox—on depression, researchers investigated whether it might aid patients with major depressive disorder who had not responded to antidepressant medications. Participants in the treatment group were given a single dose (consisting of five injections) of botulinum toxin in the area of the face between and just above the eyebrows, whereas the control group was given placebo injections. Depressive symptoms in the treatment group decreased 47 percent after six weeks, an improvement that remained through the 16-week study period. The placebo group had a 9 percent reduction in symptoms. The findings appeared in May in the Journal of Psychiatric Research. Study author M. Axel Wollmer, a psychiatrist at the University of Basel in Switzerland, believes the treatment “interrupts feedback from the facial musculature to the brain, which may be involved in the development and maintenance of negative emotions.” Past studies have shown that Botox impairs people's ability to identify others' feelings, and the new finding adds more evidence: the muscles of the face are instrumental for identifying and experiencing emotions, not just communicating them. © 2012 Scientific American

Keyword: Depression; Aggression
Link ID: 17315 - Posted: 10.02.2012

Clint Witchalls James R. Flynn is Professor Emeritus at the University of Otago, New Zealand. Flynn researches intelligence and is best known for the discovery that, over the past century, IQs have been rising at a rate of about 3 points per decade (the Flynn-effect). In advance of his new book on the subject, Clint Witchalls asked him about this and some of Professor Flynn's more recent research findings: Clint Witchalls: How has our way of thinking and of solving problems changed over the past century? James R. Flynn: Today we take it for granted that using logic on the abstract is an ability we want to cultivate and we are interested in the hypothetical. People from 1900 were not scientifically oriented but utilitarian and they used logic, but to use it on the hypothetical or on abstractions was foreign to them. Alexander Luria [a Soviet psychologist] went to talk to headmen in villages in rural Russia and he said to them: "Where there is always snow, bears are white. At the North Pole there is always snow, what colour are the bears there?" And they said: "I've only seen brown bears." And he said: "What do my words convey?" And they said: "Such a thing as not to be settled by words but by testimony." They didn't settle questions of fact by logic, they settled them by experience. Your research found that we have gained 30 points on IQ tests in a century. What is the reason? The ultimate cause of why IQs are rising is the industrial revolution. The proximate cause is how our minds differ from people in 1900 when in the test room. And the intermediate causes, of course, are more cognitively demanding work roles, more cognitively demanding leisure, more formal schooling, and smaller families. © independent.co.uk

Keyword: Intelligence; Aggression
Link ID: 17307 - Posted: 09.27.2012

By Melissa Healy Los Angeles Times Measuring human intelligence may be controversial and oh-so-very-tricky to do. But like obscenity, we think we know it when we see it. A new study, however, demonstrates a more rigorous way to see and measure differences in intelligence between individuals. It finds that connectedness among the brain's disparate regions is a key factor that separates the plodding from the penetrating. As many researchers have long suspected, intelligence does have a "seat" in the human brain: an area just behind each of the temples called the lateral prefrontal cortex. But researchers writing in the journal Neuroscience found that human behavior that is exceptionally flexible, responsive and capable of navigating complexity requires something beyond a strong and active prefrontal cortex: strong and agile runners must link that seat to brain regions involved in perception, memory, language and mobility. The researchers estimate that the strength of those connections, as measured when subjects rested between mental tasks, explains about 10% of differences in intelligence among individuals. That makes this measure an even better predictor of intelligence than brain size -- a measure that scientists believe may explain about 7% of the variation in intelligence among individuals. To detect this relationship, the Neuroscience study compared functional magnetic resonance imaging (fMRI) brain scans of 78 men and women between 18 and 40 years old with those subjects' performance on tests of cognitive performance that required "fluid intelligence" and "cognitive control." Subjects, for instance, were asked to count backwards by, say, nine, or to watch a series of visual images and then indicate whether a single image shown had been among them. Copyright 2012

Keyword: Intelligence; Aggression
Link ID: 17117 - Posted: 08.04.2012

By Maria Konnikova It’s 1879, and psychology is just about to be born. The place: the University of Leipzig. The birth parent: Wilhelm Wundt. The deed: establishing the first official university laboratory for the study of psychology, an event taken by many as the line that marks unofficial explorations from empirical, accepted science. The laboratory has four rooms and a handful of students. By the early 1880s, it will grow to an astounding six rooms—and a total of 19 students. In 1883, it will award its first doctoral degree, to the first of Wundt’s advisees, Max Friedrich, on the topic of the time-course of individual psychological processes. That same year will see the publication of the first issue of the Journal Philosophische Studien, the first journal of experimental psychology, established—fittingly—by none other than Wundt. From that point on, the future of the discipline will be assured: psychology will survive, and perhaps even flourish, with the dawn of the new century. It will not be just another experiment gone wrong. That, at least, is the most straightforward story. It’s difficult to pinpoint a date for the birth of Psychology as such. That 1879 laboratory is but one contender, and Wundt, but one possible father. But just think of how many paved the way for Wundt’s achievements. Is it fair to call him the start, or is he rather more of a point of coalescence (if that)? And how far back must we go, if we’re to be really fair? © 2012 Scientific American,

Keyword: Miscellaneous
Link ID: 17114 - Posted: 08.01.2012

by Michael Balter Many children (and adults) have heard Aesop's fable about the crow and the pitcher. A thirsty crow comes across a pitcher partly filled with water but can't reach the water with his beak. So he keeps dropping pebbles into the pitcher until the water level rises high enough. A new study finds that both young children and members of the crow family are good at solving this problem, but children appear to learn it in a very different ways from birds. Recent studies, particularly ones conducted by Nicola Clayton's experimental psychology group at the University of Cambridge in the United Kingdom have shown that members of the crow family are no birdbrains when it comes to cognitive abilities. They can make and use tools, plan for the future, and possibly even figure out what other birds are thinking, although that last claim is currently being debated. A few years ago, two members of Clayton's group showed that rooks can learn to drop stones into a water-filled tube to get at a worm floating on the surface. And last year, a team led by Clayton's graduate student Lucy Cheke reported similar experiments with Eurasian jays: Using three different experimental setups, Cheke and her colleagues found that the jays could solve the puzzle as long as the basic mechanism responsible for raising the water level was clear to the birds. To explore how learning in children might differ from rooks, jays, and other members of the highly intelligent crow family, Cheke teamed up with a fellow Clayton lab member, psychologist Elsa Loissel, to try the same three experiments on local schoolchildren aged 4 to 10 years. Eighty children were recruited for the experiments, which took place at their school with the permission of their parents. © 2010 American Association for the Advancement of Science

Keyword: Intelligence; Aggression
Link ID: 17092 - Posted: 07.26.2012

by Elizabeth Pennisi OTTAWA—With big brains comes big intelligence, or so the hypothesis goes. But there may be trade-offs as well. Humans and other creatures with large brains relative to their body size tend to have smaller guts and possibly fewer offspring. Scientists have debated for decades whether the two phenomena are related. Now a team of researchers says that they are—and that big brains do indeed make us smart. The finding comes thanks to an unusual experiment reported here yesterday at the Evolution Ottawa evolutionary biology meeting in which scientists shrank and grew the brains of guppies over several generations. "This is a real experimental result," says David Reznick, an evolutionary biologist at the University of California, Riverside, who was not involved in the study. "The earlier results were just correlations." Researchers first began to gather evidence that big brains were advantageous after 19th century U.S. biologist Hermon Bumpus examined the brains of sparrows, some of whom had succumbed in a blizzard and some of whom survived. The survivors had relatively larger brains. More recently, evolutionary biologist Alexei Maklakov from Uppsala University in Sweden found evidence that songbirds that colonize cities tend to have larger brains relative to their body size than species still confined to the countryside. The challenge of urban life might require bigger brains, he and his colleagues concluded last year in Biology Letters. Yet in humans and in certain electric fish, larger brain size seems to have trade-offs: smaller guts and fewer offspring. That's led some scientists to suggest there are constraints on how big brains can become because they are expensive to build and maintain. © 2010 American Association for the Advancement of Science.

Keyword: Evolution; Aggression
Link ID: 17026 - Posted: 07.11.2012

Meredith Wadman Loretta, Ricky, Tiffany and Torian lead increasingly quiet lives, munching peppers and plums, perching and swinging in their 16-cubic-metre glass enclosures. They are the last four chimpanzees at Bioqual, a contract firm in Rockville, Maryland, that since 1986 has housed young chimpanzees for use by the nearby National Institutes of Health (NIH). Now an animal-advocacy group is demanding that the animals' roles as research subjects is brought to an end. Researchers at the NIH’s National Institute of Allergy and Infectious Diseases (NIAID) and the Food and Drug Administration have used the juvenile chimpanzees to study hepatitis C and malaria, as well as other causes of human infection, such as respiratory syncytial virus and norovirus. But now the NIH’s demand for ready access to chimpanzees is on the wane as the scientists who relied on them retire and social and political pressures against their use grow. The four remaining chimps are set to be returned soon to their owner, the New Iberia Research Center (NIRC) near Lafayette, Louisiana. “Much of what I have done over the past years has been research in chimps,” says Robert Purcell, 76, who heads the hepatitis viruses section at the NIAID’s Laboratory of Infectious Diseases. “It’s just a good time now [to retire] as the chimps are essentially no longer available.” Last December, a report from the US Institute of Medicine concluded that most chimpanzee research was scientifically unnecessary and recommended that the NIH sharply curtail its support. © 2012 Nature Publishing Group,

Keyword: Animal Rights
Link ID: 17010 - Posted: 07.09.2012

By Jason G. Goldman Yogi Bear always claimed that he was smarter than the average bear, but the average bear appears to be smarter than once thought. Psychologists Jennifer Vonk of Oakland University and Michael J. Beran of Georgia State University have taken a testing methodology commonly used for primates and shown not only that the methodology can be more widely used, but also that bears can distinguish among differing numerosities. Numerical cognition is perhaps the best understood of the core building blocks of the mind. Decades of research have provided evidence for the numerical abilities of gorillas, chimpanzees, rhesus, capuchin, and squirrel monkeys, lemurs, dolphins, elephants, birds, and fish. Pre-linguistic human infants share the same mental modules for representing and understanding numbers as those non-human animal species. Each of these species is able to precisely count sets of objects up to three, but after that, they can only approximate the number of items in a set. Even human adults living in cultures whose languages have not developed an explicit count list must rely on approximation rather than precision for quantities larger than three. For this reason, it is easier for infants and animals to distinguish thirty from sixty than it is to distinguish thirty from forty, since the 1:2 ratio (30:60) is smaller than the 3:4 ratio (30:40). As the ratios increase, the difference between the two sets becomes smaller, making it more difficult to discriminate between them without explicit counting. Given that species as divergent as humans and mosquitofish represent number in the same ways, subject to the same (quantity-based and ratio-based) limits and constraints, it stands to reason that the ability to distinguish among two quantities is evolutionarily-ancient. © 2012 Scientific American

Keyword: Intelligence; Aggression
Link ID: 16949 - Posted: 06.21.2012

by Moheb Costandi Researchers have yet to understand how genes influence intelligence, but a new study takes a step in that direction. An international team of scientists has identified a network of genes that may boost performance on IQ tests by building and insulating connections in the brain. Intelligence runs in families, but although scientists have identified about 20 genetic variants associated with intelligence, each accounts for just 1% of the variation in IQ scores. Because the effects of these genes on the brain are so subtle, neurologist Paul Thompson of the University of California, Los Angeles, devised a new large-scale strategy for tackling the problem. In 2009, he co-founded the ENIGMA Network, an international consortium of researchers who combine brain scanning and genetic data to study brain structure and function. Earlier this year, Thompson and his colleagues reported that they had identified genetic variants associated with head size and the volume of the hippocampus, a brain structure that is crucial for learning and memory. One of these variants was also weakly associated with intelligence. Those carrying it scored on average 1.29 points better on IQ tests than others, making it one of the strongest candidate intelligence genes so far. The researchers have now used the same strategy to identify more genetic variants associated with brain structure and IQ. In the new study, they analyzed brain images and whole-genome data from 472 Australians, including 85 pairs of identical twins, 100 pairs of nonidentical twins, and their nontwin siblings. They identified 24 genetic variations within six different genes, all of which were linked to differences in the structural integrity of major brain pathways. © 2010 American Association for the Advancement of Science

Keyword: Genes & Behavior; Aggression
Link ID: 16942 - Posted: 06.20.2012

By JAMES GORMAN The extremes of animal behavior can be a source of endless astonishment. Books have been written about insect sex. The antics of dogs and cats are sometimes hard to believe. And birds, those amazing birds: They build elaborate nests, learn lyrical songs, migrate impossibly long distances. But “Gifts of the Crow,” by John N. Marzluff and Tony Angell, includes a description of one behavior that even Aesop never imagined. “On Kinkazan Island in northern Japan,” the authors write, “jungle crows pick up deer feces — dry pellets of dung — and deftly wedge them in the deer’s ears.” What!? I checked the notes at the back of the book, and this account comes from another book, written in Japanese. So I can’t give any more information on this astonishing claim, other than to say that Dr. Marzluff, of the University of Washington, and Mr. Angell, an artist and observer of birds, think that the crows do it in the spirit of fun. Deer droppings, it must be said, are only one of the crows’ gifts. The authors’ real focus is on the way that crows can give us “the ephemeral and profound connection to nature that many people crave.” To that end, however, they tell some wild anecdotes and make some surprising assertions. Many of the behaviors they describe — crows drinking beer and coffee, whistling and calling dogs and presenting gifts to people who feed them — are based on personal testimony and would seem to fall into the category of anecdote rather than science. © 2012 The New York Times Company

Keyword: Intelligence; Aggression
Link ID: 16902 - Posted: 06.12.2012

By Gary Stix “Superwoman has been rumbled,” declared a Daily Telegraph article in 2001 that chronicled how the human brain’s inability to “multitask” undercuts the prospects for a woman to juggle career and family with any measure of success. The brain as media icon has emerged repeatedly in recent years as new imaging techniques have proliferated—and, as a symbol, it seems to confuse as much as enlighten. The steady flow of new studies that purport to reduce human nature to a series of illuminated blobs on scanner images have fostered the illusion that a nouveau biological determinism has arrived. More often than not, a “neurobiological correlate”— tying together brain activity with a behavioral attribute (love, pain, aggression)—supplies the basis for a journal publication that translates instantly into a newspaper headline. The link between blob and behavior conveys an aura of versimilitude that often proves overly seductive to the reporter hard up to fill a health or science quota. A community of neuroscience bloggers, meanwhile, has taken on the responsibility of rectifying some of these misinterpretations. A study published last week by University College of London researchers—“Neuroscience in the Public Sphere”—tried to imbue this trend with more substance by quantifying and formally characterizing it. “Brain-based information possesses rhetorical power,” the investigators note. “Logically irrelevant neuroscience information [the result of the multitude of correlations that turn up] imbues an argument with authoritative, scientific credibility.” © 2012 Scientific American,

Keyword: Miscellaneous
Link ID: 16754 - Posted: 05.05.2012

By Brian Alexander Good news for all those who ever had a teacher or a parent say “If you would just apply yourself you could learn anything! You’re only using 10 percent of your brain!” All those people were wrong. If we did use only 10 percent of our brains we’d be close to dead, according to Eric Chudler, director of the Center for Sensorimotor Neural Engineering at the University of Washington, who maintains an entertaining brain science website for kids. “When recordings are made from brain EEGs, or PET scans, or any type of brain scan, there’s no part of the brain just sitting there unused,” he said. Larry Squire, a research neuroscientist with the Veterans Administration hospital in San Diego, and at the University of California San Diego, pointed out that “any place the brain is damaged there is a consequence.” Damaged brains may have been where this myth originated. During the first half of the last century, a pioneering neuroscientist named Karl Lashley experimented on rodents by excising portions of their brains to see what happened. When he put these rodents in mazes they’d been trained to navigate, he found that animals with missing bits of brain often successfully navigated the mazes. This wound up being transmuted into the idea humans must be wasting vast brain potential. With the rise of the human potential movement in the 1960s, some preached that all sorts of powers, including bending spoons and psychic abilities, were laying dormant in our heads and that all we had to do was get off our duffs and activate them. © 2012 msnbc.com

Keyword: Brain imaging
Link ID: 16676 - Posted: 04.19.2012

by Andy Coghlan A massive genetics study relying on fMRI brain scans and DNA samples from over 20,000 people has revealed what is claimed as the biggest effect yet of a single gene on intelligence – although the effect is small. There is little dispute that genetics accounts for a large amount of the variation in people's intelligence, but studies have consistently failed to find any single genes that have a substantial impact. Instead, researchers typically find that hundreds of genes contribute. Following a brain study on an unprecedented scale, an international collaboration has now managed to tease out a single gene that does have a measurable effect on intelligence. But the effect – although measurable – is small: the gene alters IQ by just 1.29 points. According to some researchers, that essentially proves that intelligence relies on the action of a multitude of genes after all. "It seems like the biggest single-gene impact we know of that affects IQ," says Paul Thompson of the University of California, Los Angeles, who led the collaboration of 207 researchers. "But it's not a massive effect on IQ overall," he says. The variant is in a gene called HMGA2, which has previously been linked with people's height. At the site of the relevant mutation, the IQ difference depends on a change of a single DNA "letter" from C, standing for cytosine, to T, standing for thymine. © Copyright Reed Business Information Ltd.

Keyword: Intelligence; Aggression
Link ID: 16667 - Posted: 04.17.2012

Chris McManus, professor of psychology and medical education at University College London, responds: if by intelligent you mean someone who performs better on IQ tests, the simple answer is no. Studies in the U.K., U.S. and Australia have revealed that left-handed people differ from right-handers by only one IQ point, which is not noteworthy. If by intelligent you mean someone who performs better on IQ tests, the simple answer is no. Studies in the U.K., U.S. and Australia have revealed that left-handed people differ from right-handers by only one IQ point, which is not noteworthy. Left-handedness is, however, much more common among individuals with severe learning difficulties, such as mental retardation. A slightly higher proportion of left-handers have dyslexia or a stutter. Other problems, such as a higher rate of accidents reported in left-handers, mostly result from a world designed for the convenience of right-handers, with many tools not made for left-handed use. Although some people claim that a higher percentage of left-handers are exceptionally bright, large research studies do not support this idea. If by smarter you mean more talented in certain areas, left-handers may have an advantage. Left-handers’ brains are structured differently from right-handers’ in ways that can allow them to process language, spatial relations and emotions in more diverse and potentially creative ways. Also, a slightly larger number of left-handers than right-handers are especially gifted in music and math. A study of musicians in professional orchestras found a significantly greater proportion of talented left-handers, even among those who played instruments that seem designed for right-handers, such as violins. Similarly, studies of adolescents who took tests to assess mathematical giftedness found many more left-handers in the population. The fact that mathematicians are often musical may not be a coincidence. © 2012 Scientific American,

Keyword: Laterality; Aggression
Link ID: 16656 - Posted: 04.16.2012