Links for Keyword: Intelligence

Follow us on Facebook and Twitter, or subscribe to our mailing list, to receive news updates. Learn more.

Links 81 - 100 of 237

Crows make monkeys out of chimps in mental test

Emma Young Crows seem to be able to use causal reasoning to solve a problem, a feat previously undocumented in any other non-human animal, including chimps. Alex Taylor at the University of Auckland, New Zealand, and his team presented six New Caledonian crows with a series of "trap-tube" tests. A choice morsel of food was placed in a horizontal Perspex tube, which also featured two round holes in the underside, with Perspex traps below. For most of the tests, one of the holes was sealed, so the food could be dragged across it with a stick and out of the tube to be eaten. The other hole was left open, trapping the food if the crows moved it the wrong way. Three of the crows solved the task consistently, even after the team modified the appearance of the equipment. This suggested that these crows weren't using arbitrary features – such as the colour of the rim of a hole – to guide their behaviour. Instead they seemed to understand that if they dragged food across a hole, they would lose it. To investigate further, the team presented the crows with a wooden table, divided into two compartments. A treat was at the end of each compartment, but in one, it was positioned behind a rectangular trap hole. To get the snack, the crow had to consistently choose to retrieve food from the compartment without the hole. © Copyright Reed Business Information Ltd

Related chapters from BP7e: Chapter 1: Biological Psychology: Scope and Outlook; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 1: An Introduction to Brain and Behavior
Link ID: 12054 - Posted: 06.24.2010

The 10 smartest animals

We humans have the ability to learn, to reason and solve problems. We're self-aware, and we’re also conscious of the presence, thoughts and feelings of others. We make tools and practice the art of deception. We're creative. We think abstractly. We have language and use it to express complex ideas. All of these are arguably signs of intelligence. Scientists may not agree on the best and fullest definition of intelligence – but they generally agree that humans are highly intelligent. Other members of the animal kingdom exhibit signs of intelligence as well, and some scientists might say the definition of animal vs. human intelligence is merely a matter of degree – a point that was brought home in 2005 when the London Zoo put “Homo sapiens” on display in the exhibit pictured here. Click the "Next" arrow above to learn about nine other species that stand out for their smarts. © 2008 MicrosoftMSN

Big bird-brains boost beneficial behaviours

Bigger brained birds have a better chance of survival, according to a study that looked at the mortality rates of 200 bird species around the world. Daniel Sol at the Autonomous University of Barcelona in Spain and colleagues looked for a correlation between two factors. The first factor was the birds' mortality – a measure of how likely individuals are to survive from one year to the next using data from tagged birds – and their brain-to-body-weight ratio. Statistical analysis showed that birds with bigger brains relative to their weight were more likely to survive, which could explain why birds with small brains, such as pheasants, find it harder to avoid a moving car than those with larger brains, such as magpies. The finding may seem intuitive, but it is not necessarily about birds with bigger brains being “smarter” than others. In fact, Sol is not sure what makes bigger-brained birds more likely to survive, but reckons it has something to do with their ability to better adapt to changes to their environment. This idea is called the "cognitive buffer hypothesis" and was originally put forward to explain why animals – humans included – have evolved larger brains, despite the resource cost of developing and maintaining that brain. Previous research suggests that species with larger brains have more flexible behaviours, Sol says. Indeed, in 2005 he and colleagues observed birds inventing new foraging behaviours to adapt to changing environments: swallows feeding on insects attracted to street lights, for instance, or birds adopting new types of food (Proceedings of the National Academy of Science, DOI:10.1073/pnas.0408145102). © Copyright Reed Business Information Ltd.

Scans suggest IQ scores reflect brain structure

Jim Giles Researchers say that a remarkable data set on the developing brain adds to the idea that IQ is a meaningful concept in neuroscience. The study, which is published on page 676 of this issue, suggests that performance in IQ tests is associated with changes in the brain during adolescence. Claims that IQ is a valid measure of intelligence tend to attract angry responses, in part because of studies that have attempted to link group differences in IQ with race. In their 1994 book The Bell Curve, political scientist Charles Murray and psychologist Richard Herrnstein argued that the lower-income status of some US ethnic minorities was linked to below-average IQ scores among those groups. These were in turn attributed to mainly genetic factors. Before that, Harvard University entomologist Edward Wilson provoked outrage with work that proposed evolutionary explanations for human behaviour and individual differences in intelligence; critics called the work racist. And this month, the journal Intelligence printed an editorial note defending its policy regarding the publication of controversial papers. The note comes after a study linking IQ and skin colour (D. I. Templer and H. Arikawa Intelligence 34, 121–139; 2006), published online last November, prompted a string of complaints from scientists. ©2006 Nature Publishing Group

Related chapters from BP7e: Chapter 1: Biological Psychology: Scope and Outlook; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 1: An Introduction to Brain and Behavior; Chapter 13: Memory, Learning, and Development
Link ID: 8733 - Posted: 06.24.2010

African grey parrot is first bird to comprehend numerical concept akin to zero

Waltham, Mass. – A Brandeis University researcher has shown that an African grey parrot with a walnut-sized brain understands a numerical concept akin to zero – an abstract notion that humans don't typically understand until age three or four, and that can significantly challenge learning-disabled children Strikingly, Alex, the 28-year-old parrot who lives in a Brandeis lab run by comparative psychologist and cognitive scientist Dr. Irene Pepperberg, spontaneously and correctly used the label "none" during a testing session of his counting skills to describe an absence of a numerical quantity on a tray. This discovery prompted a series of trials in which Alex consistently demonstrated the ability to identify zero quantity by saying the label "none." Dr. Pepperberg's research findings, published in the current issue of The Journal of Comparative Psychology, add to a growing body of scientific evidence that the avian brain, though physically and organizationally somewhat different from the mammalian cortex, is capable of higher cognitive processing than previously thought. Chimpanzees and possibly squirrel monkeys show some understanding of the concept of zero, but Alex is the first bird to demonstrate an understanding of the absence of a numerical set, Dr. Pepperberg noted. "It is doubtful that Alex's achievement, or those of some other animals such as chimps, can be completely trained; rather, it seems likely that these skills are based on simpler cognitive abilities they need for survival, such as recognition of more versus less," explained Dr. Pepperberg.

VCU STUDY SHOWS BIG-BRAINED PEOPLE ARE SMARTER

RICHMOND, Va. – People with bigger brains are smarter than their smaller-brained counterparts, according to a study conducted by a Virginia Commonwealth University researcher published in the journal “Intelligence.” The study, published on line June 16, could settle a long-standing scientific debate about the relationship between brain size and intelligence. Ever since German anatomist and physiologist Frederick Tiedmann wrote in 1836 that there exists “an indisputable connection between the size of the brain and the mental energy displayed by the individual man,” scientists have been searching for biological evidence to prove his claim. “For all age and sex groups, it is now very clear that brain volume and intelligence are related,” said lead researcher Michael A. McDaniel, Ph.D., an industrial and organizational psychologist who specializes in the study of intelligence and other predictors of job performance. The study is the most comprehensive of its kind, drawing conclusions from 26 previous – mostly recent – international studies involving brain volume and intelligence. It was only five years ago, with the increased use of MRI-based brain assessments, that more data relating to brain volume and intelligence became available.

Related chapters from BP7e: Chapter 1: Biological Psychology: Scope and Outlook
Related chapters from MM:Chapter 1: An Introduction to Brain and Behavior
Link ID: 7520 - Posted: 06.24.2010

New research opens a window on the minds of plants

By Patrik Jonsson | Correspondent of The Christian Science Monitor RALEIGH, N.C. – Hardly articulate, the tiny strangleweed, a pale parasitic plant, can sense the presence of friends, foes, and food, and make adroit decisions on how to approach them. Mustard weed, a common plant with a six-week life cycle, can't find its way in the world if its root-tip statolith - a starchy "brain" that communicates with the rest of the plant - is cut off. The ground-hugging mayapple plans its growth two years into the future, based on computations of weather patterns. And many who visit the redwoods of the Northwest come away awed by the trees' survival for millenniums - a journey that, for some trees, precedes the Parthenon. As trowel-wielding scientists dig up a trove of new findings, even those skeptical of the evolving paradigm of "plant intelligence" acknowledge that, down to the simplest magnolia or fern, flora have the smarts of the forest. Some scientists say they carefully consider their environment, speculate on the future, conquer territory and enemies, and are often capable of forethought - revelations that could affect everyone from gardeners to philosophers. Indeed, extraordinary new findings on how plants investigate and respond to their environments are part of a sprouting debate over the nature of intelligence itself. Copyright © 2005 The Christian Science Monitor.

Dualists from Birth

Ethan Remmel When I teach about the mind/body issue, I am often struck by how many of my students are dualists. I'm not talking about modern hedged positions such as property dualism or explanatory dualism; I'm talking about good old–fashioned Cartesian substance dualism, which maintains that our physical bodies/brains are inhabited by immaterial souls/minds and that body and soul are intimately linked, yet distinct and dissociable (at death, for example, when the soul may depart the body). And these students are not wild–eyed religious evangelists; they are sober–minded science majors. I pose what seem to me to be serious problems with this position: For example, how could material and immaterial substances interact? But many of these students seem unable even to see the problem. I end up perplexed by their lack of perplexity. Paul Bloom has an explanation. In his new book, Descartes' Baby, he maintains that dualism is innate—that is, not learned. We naturally see the world as containing both material objects, which are governed by physical laws, and mental entities, whose behavior is intentional and goal–directed. Some things in the world, such as people, can be seen either way, as physical bodies or as intentional agents. However, as Bloom describes, we tend toward the latter interpretation whenever possible, even attributing intentions to animated shapes on a computer screen if they move in certain ways. According to Bloom, dualism is the product not of nurture but of nature—specifically, evolution by natural selection. It was adaptive for our ancestors to be able to predict the behavior of physical objects and social creatures (especially conspecifics). © Sigma Xi, The Scientific Research Society

MEASURES TAKEN TO COMPENSATE FOR RISING IQ SCORES AFFECT WHO IS DIAGNOSED WITH MENTAL RETARDATION

Making IQ Tests Harder Due To Flynn Effect Has Educational, Financial, Legal and Military Recruiting Implications WASHINGTON — The steady rising of IQ scores over the last century – known as the Flynn effect – causes IQ tests norms to become obsolete over time. To counter this effect, IQ tests are “renormed” (made harder) every 15-20 years by resetting the mean score to 100 to account for the previous gains in IQ scores. But according to new research, such renorming may have unintended consequences, particularly in the area of special education placements for children with borderline or mild mental retardation. The findings are reported on in the October issue of American Psychologist, a journal of the American Psychological Association (APA). Researchers Tomoe Kanaya, M.A. and Stephen J. Ceci, Ph.D., of Cornell University and Matthew H. Scullin, Ph.D., of West Virginia University used IQ data from nearly 9,000 school psychologist special education assessments from nine school districts across the U.S. to document how the Flynn effect influences mental retardation diagnoses for several years after a new test is introduced. The students (ages 6 – 17) were from different geographical regions, neighborhood types and socioeconomic status. © 2003 American Psychological Association

The ghost hunters

Scientists and novelists share insights into the enduring mystery of human consciousness BY JAY TOLSON Four years ago, as he tells it, philosopher Colin McGinn met the English novelist Edward St Aubyn at a conference on human consciousness at the University of Arizona. A couple of years later, McGinn discovered that he had become a character in St Aubyn's new novel, A Clue to the Exit. "McGinn," Charlie Fairburn (the screenwriter-protagonist who has been told that he has only six months to live), and others are returning on a train from an Oxford conference on consciousness. Amid much heady talk, "McGinn" provides Fairburn with an argument for why science will never adequately explain what consciousness is (an argument that the real McGinn published in his 1999 book, The Mysterious Flame).Perhaps paradoxically, the explanation brings Fairburn peace of mind. Although this story within a story does not appear in David Lodge's new book, Consciousness & the Novel, it is an apt illustration of the phenomenon to which he calls attention: Consciousness, though long an indirect concern of fiction, has recently become the explicit preoccupation of many literary novelists–at the same time that scientists in many fields have taken a renewed interest in the subject. This is more than a coincidence, Lodge says. It is a conjunction of interests that illuminates both the problem of consciousness andthe respective methods, goals, and limitations of the novelists and scientists who are engaged with it. Even more valuable to Lodge, who is a novelist and a former professor of literature at the University of Birmingham, the two ways of looking at consciousness shed new light on the old questions of how literature does what it does and even ''why literature exists, why we need it, and why we value it." On the science side, Lodge points to a confluence of new approaches, theories, and technologies. These include advances in computer science that give promise of constructing artificial intelligence and even consciousness itself; a new understanding of the neurochemistry behind different mental states and moods; and a host of brain-scanning and brain-imaging techniques. All have boosted confidence that close scrutiny of the brain (the hardware) will eventually explain mind and consciousness (the software), thus dissolving the mystery of the "ghost in the machine." Copyright © 2002 U.S. News & World Report, L.P.

Consciousness and the Novel, by David Lodge

A consciousness-raising study of the many minds of David Lodge By Nick Groom Craig Raine, in the interview that concludes this collection, asks if David Lodge thinks he has a distinctive style and if it could be parodied. Lodge does not know: "I think I'm rather a ventriloqual kind of novelist. I imitate a lot of different voices rather than having an obvious distinctive one of my own." Lodge's fiction is famous for pastiches of other writers, but he could as easily be talking about his criticism. Consciousness and the Novel consists of recent lectures, essays, introductions and reviews, in which several Lodges emerge: the dapper professor lecturing on the latest fashionable ideas; the meticulous teacher outlining the fascination of Howards End ; the impatient dilettante carelessly taking quotations from the web and video sleeves; and the chatty, urbane champion of Evelyn Waugh. By writing differently on each subject, be becomes a different writer for each – the most striking thing about this collection. At one level, then, this is simply the latest "best of", showing Lodge's range as a critical impressionist. The blurb, however, makes the claim that the book is about how the latest theories of the mind help us to understand how the novel represents human consciousness. So Lodge is interested in literature and "consciousness studies": artificial intelligence, evolutionary biology and so forth. All this boils down to the question of how the brain is "hardwired" and how competing "software" programmes for, say, "identity" or "soul" are run on the biological system. But by writing in so many styles, Lodge presents a powerful argument against the new maps of consciousness proposed by trendy polemicists such as Steven Pinker. © 2002 Independent Digital (UK) Ltd

Related chapters from BP7e: Chapter 1: Biological Psychology: Scope and Outlook; Chapter 19: Language and Hemispheric Asymmetry
Related chapters from MM:Chapter 1: An Introduction to Brain and Behavior; Chapter 15: Language and Our Divided Brain
Link ID: 3053 - Posted: 06.24.2010

Clever Crows, Complex Cognition?

by Gisela Telis Called “feathered apes” for their simianlike smarts, crows use tools, understand physics, and recognize themselves and humans. But new research suggests that the brainy birds may be even smarter than was previously thought. Given a complex problem and an assortment of tools, New Caledonian crows came up with a creative solution that hints at higher-order thinking. A native of New Caledonia and the Loyalty Islands in the Pacific Ocean, the New Caledonian crow makes tools from sticks or leaves and uses these to draw tasty grubs from hollows in trees. That in itself wouldn’t be so impressive—even some insects use tools this way—but the crows also combine tools when they needed to. In a 2007 experiment conducted by graduate student Alex Taylor and colleagues at the University of Auckland in New Zealand, the crows used a shorter stick to grab another that was long enough to get food outside their reach. This kind of action seems to indicate insight or reasoning. But not everyone was convinced, says Taylor. “Some scientists suggested the tools became valuable in themselves because they were associated with food,” he says. That would mean the birds sought each stick because they wanted it, not because they understood the stick’s potential function. The distinction, although subtle, marks the difference between high- and low-level learning, and it speaks to a central question of cognition research: How do you determine whether an animal is thinking through its actions, or simply learning through association a series of behaviors and combining them? © 2010 American Association for the Advancement of Science

Related chapters from BP7e: Chapter 6: Evolution of the Brain and Behavior; Chapter 1: Biological Psychology: Scope and Outlook
Related chapters from MM:Chapter 0: ; Chapter 1: An Introduction to Brain and Behavior
Link ID: 13997 - Posted: 06.24.2010

The Brain Why Athletes Are Geniuses

by Carl Zimmer The qualities that set a great athlete apart from the rest of us lie not just in the muscles and the lungs but also between the ears. That’s because athletes need to make complicated decisions in a flash. One of the most spectacular examples of the athletic brain operating at top speed came in 2001, when the Yankees were in an American League playoff game with the Oakland Athletics. Shortstop Derek Jeter managed to grab an errant throw coming in from right field and then gently tossed the ball to catcher Jorge Posada, who tagged the base runner at home plate. Jeter’s quick decision saved the game—and the series—for the Yankees. To make the play, Jeter had to master both conscious decisions, such as whether to intercept the throw, and unconscious ones. These are the kinds of unthinking thoughts he must make in every second of every game: how much weight to put on a foot, how fast to rotate his wrist as he releases a ball, and so on. In recent years neuroscientists have begun to catalog some fascinating differences between average brains and the brains of great athletes. By understanding what goes on in athletic heads, researchers hope to understand more about the workings of all brains—those of sports legends and couch potatoes alike. As Jeter’s example shows, an athlete’s actions are much more than a set of automatic responses; they are part of a dynamic strategy to deal with an ever-changing mix of intricate challenges. Even a sport as seemingly straightforward as pistol shooting is surprisingly complex. A marksman just points his weapon and fires, and yet each shot calls for many rapid decisions, such as how much to bend the elbow and how tightly to contract the shoulder muscles.

Related chapters from BP7e: Chapter 11: Motor Control and Plasticity; Chapter 1: Biological Psychology: Scope and Outlook
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 1: An Introduction to Brain and Behavior
Link ID: 13985 - Posted: 06.24.2010

Is a Dolphin a Person?

by David Grimm, SAN DIEGO—Are dolphins as smart as people? And if so, shouldn't we be treating them a bit better than we do now? Those were the topics of discussion at a session on the ethical and policy implications of dolphin intelligence here today at the annual meeting of the American Association for the Advancement of Science (which publishes ScienceNOW). First up, just how smart are dolphins? Researchers have been exploring the question for three decades, and the answer, it turns out, is pretty darn smart. In fact, according to panelist Lori Marino, an expert on cetacean neuroanatomy at Emory University in Atlanta, Georgia, they may be Earth's second smartest creature (next to humans, of course). Marino bases her argument on studies of the dolphin brain. Bottlenose dolphins have bigger brains than humans (1600 grams versus 1300 grams), and they have a brain-to-body-weight ratio greater than great apes do (but lower than humans). "They are the second most encephalized beings on the planet," says Marino. But it's not just size that matters. Dolphins also have a very complex neocortex, the part of the brain responsible for problem solving, self awareness, and variety of other traits we associate with human intelligence. And researchers have found gangly neurons called Von Economo neurons, which in humans and apes have been linked to emotions, social cognition, and even theory of mind—the ability to sense what others are thinking. Overall, said Marino, "dolphin brains stack up quite well to human brains." © 2010 American Association for the Advancement of Science.

Physics? It's All the Same to Birds and Babies

By Michael Torrice Even with their tiny bird brains, rooks comprehend basic principles of physics at the same level as a 6-month-old baby--and beyond that of chimpanzees--a new study reports. But whether this understanding conveys any advantages remains an open question. Rooks and other members of the crow family can manipulate tools and solve laboratory puzzles like those of Aesop's fables. Some scientists believe that these feats suggest the birds have a sophisticated understanding of physical principles—--an understanding that allows them to solve problems they wouldn't encounter in the real world. To further test the theory, Christopher Bird, a zoologist at the University of Cambridge in the United Kingdom, and his colleague Nathan Emery at of Queen Mary, University of London, "quizzed" rooks on a basic concept of physics they call "support." The duo adapted a standard experiment: Infants and other primates know that an object will fall if something is not holding it up; they stare for longer than normal at images of a ball or banana floating in mid air, for example, suggesting they know that something unusual is going on. Rooks, it turns out, do the same. The researchers set up a peep hole for the birds to peer into. (Rooks are natural peeping tToms and will spy through small holes or cracks looking for other rooks.) On the other side were images depicting eggs in various situations, both possible and impossible. Some eggs rested on a table, whilereas others floated above it. And in a more subtle twist, the researchers added a picture of an egg hovering in the air while its side or bottom touched the table's side. © 2009 American Association for the Advancement of Science

Bear-Proof Can Is Pop-Top Picnic for a Crafty Thief

By LISA W. FODERARO NORTH ELBA, N.Y. — It was built to be impenetrable, from its “super rugged transparent polycarbonate housing” to its intricate double-tabbed lid that would keep campers’ food in and bears’ paws out. The BearVault 500 withstood the ravages of the test bears at the Folsom City Zoo in California. It has stymied mighty grizzlies weighing up to 1,000 pounds in the backcountry of Yellowstone National Park. But in one corner of the Adirondacks, campers started to notice that the BearVault, a popular canister designed to keep food and other necessities safe, was being compromised. First through circumstantial evidence, then from witness reports, it became clear that in most cases, the conqueror was a relatively tiny, extremely shy middle-aged black bear named Yellow-Yellow. Some canisters fail in the testing stage when large bears are able to rip off the lid. But wildlife officials say that Yellow-Yellow, a 125-pound bear named for two yellow ear tags that help wildlife officials keep tabs on her, has managed to systematically decipher a complex locking system that confounds even some campers. In the process, she has emerged as a near-mythical creature in the High Peaks region of the northeastern Adirondacks. “She’s quite talented,” said Jamie Hogan, owner of BearVault, based in San Diego. “I’m an engineer, and if one genius bear can do it, sooner or later there might be two genius bears. We’re trying to work on a new design that we can hopefully test on her.” Copyright 2009 The New York Times Company

Mosquito fish count comrades to stay alive

By Bruce Bower Mosquito fish don’t just count on each other for protection from predators — they literally count each other for such protection. These guppylike fish can use numerical information to identify the larger of two nearby groups of fellow fish, report psychologist Marco Dadda of the University of Padova in Italy and his colleagues in an upcoming Cognition. That’s a useful skill to have, the researchers say. Larger groups, or shoals, offer a more effective shield against bigger fish with empty bellies. The researchers allowed individual mosquitofish in a tank to see groups of other fish, but barricades prevented them from seeing an entire group at once. When viewing fish one at a time in each of two groups, mosquito fish spent much more time near larger groups, Dadda and his colleagues report. The fish preferred groups of three over two fish and groups with eight fish over four fish. “We have provided the first evidence that fish are capable of selecting the larger group of social companions by relying exclusively on numerical information,” Dadda says. In two earlier studies, Dadda’s group demonstrated that mosquito fish can distinguish between large quantities, such as 16 versus 8, provided that the numerical ratio is at least 2:1. Such distinctions draw on an ability to estimate large amounts without counting, such as noting the greater area or density of the larger of two shoals, the researchers say. © Society for Science & the Public 2000 - 2009

Related chapters from BP7e: Chapter 6: Evolution of the Brain and Behavior; Chapter 19: Language and Hemispheric Asymmetry
Related chapters from MM:Chapter 0: ; Chapter 15: Language and Our Divided Brain
Link ID: 12965 - Posted: 06.24.2010

The Coming Superbrain

By JOHN MARKOFF Mountain View, Calif. — It’s summertime and the Terminator is back. A sci-fi movie thrill ride, “Terminator Salvation” comes complete with a malevolent artificial intelligence dubbed Skynet, a military R.&D. project that gained self-awareness and concluded that humans were an irritant — perhaps a bit like athlete’s foot — to be dispatched forthwith. The notion that a self-aware computing system would emerge spontaneously from the interconnections of billions of computers and computer networks goes back in science fiction at least as far as Arthur C. Clarke’s “Dial F for Frankenstein.” A prescient short story that appeared in 1961, it foretold an ever-more-interconnected telephone network that spontaneously acts like a newborn baby and leads to global chaos as it takes over financial, transportation and military systems. Today, artificial intelligence, once the preserve of science fiction writers and eccentric computer prodigies, is back in fashion and getting serious attention from NASA and from Silicon Valley companies like Google as well as a new round of start-ups that are designing everything from next-generation search engines to machines that listen or that are capable of walking around in the world. A.I.’s new respectability is turning the spotlight back on the question of where the technology might be heading and, more ominously, perhaps, whether computer intelligence will surpass our own, and how quickly. Copyright 2009 The New York Times Company

Fact or Fiction: When It Comes to Intelligence, Does Brain Size Matter?

By Kayt Sukel Research has shown that lead kills neurons (nerve cells), resulting in smaller brains. It has long been hypothesized that such changes in the brain caused by childhood lead exposure may be behind a higher incidence of poor cognitive performance and criminal behavior. And although it is difficult to disentangle the confounding effects of race, class and economics, a recent study by Kim Dietrich, a professor of environmental health at the University of Cincinnati, found that individuals who suffered from the highest lead exposure as children had the smallest brain sizes—as well as the most arrests. "That early lead exposure was associated with smaller volumes of cortical gray matter [the parts of the brain rich in neural cell bodies and synapses] in the prefrontal area," he says. "And the fact that we saw both criminal behavior and volume loss in this critical area for executive function is probably more than just a coincidence." That may be so, however, new scientific studies across several animal species, including humans, are challenging the notion that brain size alone is a measure of intelligence. Rather, scientists now argue, it is a brain's underlying organization and molecular activity at its synapses (the communication junctions between neurons through which nerve impulses pass) that dictate intelligence. Two years ago, Paul Manger, a professor of health sciences at the University of the Witwatersrand in Johannesburg, South Africa, caused quite a stir when he referred to the beloved bottlenose dolphin, owner of a large, nearly human-size brain, as "dumber than a goldfish." © 1996-2009 Scientific American Inc.

Searching for Intelligence in Our Genes

By Carl Zimmer In Robert Plomin’s line of work, patience is essential. Plomin, a behavioral geneticist at the Institute of Psychiatry in London, wants to understand the nature of intelligence. As part of his research, he has been watching thousands of children grow up. Plomin asks the children questions such as “What do water and milk have in common?” and “In what direction does the sun set?” At first he and his colleagues quizzed the children in person or over the telephone. Today many of those children are in their early teens, and they take their tests on the Internet. In one sense, the research has been a rousing success. The children who take the tests are all twins, and throughout the study identical twins have tended to get scores closer to each other than those of nonidentical twins, who in turn have closer scores than unrelated children. These results—along with similar ones from other studies—make clear to the scientists that genes have an important influence on how children score on intelligence tests. But Plomin wants to know more. He wants to find the specific genes that are doing the influencing. And now he has a tool for pinpointing genes that he could not have even dreamed of when he began quizzing children. Plomin and his colleagues have been scanning the genes of his subjects with a device called a microarray, a small chip that can recognize half a million distinctive snippets of DNA. The combination of this powerful tool with a huge number of children to study meant that he could detect genes that had only a tiny effect on the variation in scores. © 1996-2008 Scientific American Inc.

Previous Page | Next Page

Links By Chapter:

Links for Keyword: Intelligence