By MARIA CHENG LONDON - Lithium doesn't help patients with ALS, or Lou Gehrig's disease, contrary to previous study results, new research says. Results from a small study published two years ago suggested the drug, often used for depression, could slow the fatal neurological disorder. Many ALS sufferers and their families rushed to try it, spearheading a patient-led effort to test lithium without doctors. In the first trial to scientifically assess whether lithium works for Lou Gehrig's disease, doctors found it had no effect — and stopped the study early because it seemed futile. The results were published online Tuesday in the medical journal, Lancet Neurology. American and Canadian doctors enrolled 84 patients with Lou Gehrig's disease into their study across both countries. About half the patients got lithium and riluzole, the standard drug used for the disease. The other half got riluzole plus placebo pills. After nearly six months, researchers didn't see any difference: 22 of the 40 patients in the lithium group had gotten worse versus 20 of 44 patients in the placebo group. Patients on lithium were more likely to have fallen and suffer back pain. The study was funded by the U.S. National Institute of Neurological Disorders and Stroke, the ALS Association and the ALS Society of Canada. Copyright 2010 The Associated Press.

Keyword: ALS-Lou Gehrig's Disease
Link ID: 13946 - Posted: 06.24.2010

By BENEDICT CAREY MEDFORD, Mass. — The woman was afraid and alone, a fragile soul in a wheelchair who had managed to stuff a few possessions into a plastic garbage bag before being evacuated. Like many of the Hurricane Katrina refugees who straggled into Baton Rouge, La., in the summer of 2005, she needed more than food and shelter. She needed company, sympathy — someone, anyone, to see and feel her loss — and searched the face of her assigned social worker in vain. But the social worker, barely out of college, seemed somehow emotionally removed. Something was missing. “I could see the breakdown in the emotional connection between us, could see it happening and there was nothing I could do,” said Kathleen Bogart, 28, the social worker who is now a psychology researcher at Tufts University here. Ms. Bogart has Moebius syndrome, a rare congenital condition named for a 19th-century neurologist that causes facial paralysis. When the people she helped made a sad expression, she continued, “I wasn’t able to return it. I tried to do so with words and tone of voice, but it was no use. Stripped of the facial expression, the emotion just dies there, unshared. It just dies.” Researchers have long known that facial expressions are crucial to social interaction and have categorized them in great detail. They know which expressions are universal; they can distinguish slight differences in expression, for example between a polite smile and a genuine one. Copyright 2010 The New York Times Company

Keyword: Emotions
Link ID: 13945 - Posted: 06.24.2010

by Emma Young "THERE is no great genius without a tincture of madness." So wrote the Roman philosopher Seneca, nearly 2000 years ago. Today it is routine for creative geniuses from history to get retrospective diagnoses of mental illness - some more believable than others. Schizophrenia and other forms of psychosis are the most common illnesses cited, with Newton and Einstein among the most famous subjects. Vincent van Gogh and Virginia Woolf have been linked with bipolar disorder. Few would argue that full-blown psychosis is conducive to creative accomplishment, but perhaps a little bit helps. Psychiatrists view mental health as a spectrum, with serious illness at one end and "normality" at the other. Perhaps those in the middle have enhanced creative tendencies. Some evidence comes from considering the relative dominance of the right and left hemispheres of the brain. There is much dubious pop psychology written about "right-brain people" and "left-brain people", but it is accepted that the left side is mainly involved in language and logical analysis, while the right side is more involved in creative thought. Various techniques for studying dominance do seem to show that people with schizophrenia have more right-brain activity. There is also genetic evidence relating to a protein called neuregulin 1, which is involved in brain development in the womb. Jeremy Hall of the University of Edinburgh, UK, found that a mutation in the gene that codes for the protein is linked to a higher risk of schizophrenia. And last year, Szabolcs Kéri at Semmelweis University in Hungary found that people with two copies of the mutation scored higher on a creativity test than people with one copy, who in turn scored higher than people with no copies (Psychological Science, vol 20, p 1070). © Copyright Reed Business Information Ltd.

Keyword: Schizophrenia; Depression
Link ID: 13944 - Posted: 06.24.2010

By Scott O. Lilienfeld and Hal Arkowitz The notion that men have shorter fuses than women has acquired the status of a psychological shibboleth. More than 30 years ago Stanford University psychologists Eleanor Maccoby and Carol Jacklin concluded in an influential book that sex differences were minimal in most psychological traits but considerable when it comes to aggression. This opinion has endured ever since. Were Maccoby and Jacklin right? Recent research bears out the broad brushstrokes of their claim but reveals that women can be equally, if less dangerously, belligerent. In 1995 the late psychologist David Lykken of the University of Minnesota wrote that if we could magically place all boys and men between the ages of 12 and 28 in a cryogenic freeze, we would slash the rate of violent crime by two thirds. The data bear out Lykken’s thought experiment. In the U.S., the rate of violent crime for girls and women aged 10 and older is one in 56; the corresponding figure among their male counterparts is one in nine. Men commit close to 90 percent of the murders in the U.S. and more murders than women in all the countries researchers have examined, according to a 1999 report by psychologist Anne Campbell of Durham University in England. Indeed, investigators have consistently found that short of criminal activity, men exhibit more frequent and more extreme levels of physical aggression with one exception: in domestic disputes, as we will see, the tables are often turned. In a 2004 mathematical synthesis of 196 studies (known as a meta-analysis), psychologist John Archer of the University of Central Lancashire in England found that men are more physically aggressive (by various measures) than women across all ages, with the difference peaking between the ages of 20 and 30. © 2010 Scientific American

Keyword: Aggression; Sexual Behavior
Link ID: 13943 - Posted: 06.24.2010

By Michael Shermer In the 1922 poem The Waste Land, T. S. Eliot writes, cryptically: Who is the third who always walks beside you?/When I count, there are only you and I together /But when I look ahead up the white road/There is always another one walking beside you. In his footnotes to this verse, Eliot explained that the lines “were stimulated by the account of one of the Antarctic expeditions [Ernest Shackleton’s] ... that the party of explorers, at the extremity of their strength, had the constant delusion that there was one more member than could actually be counted.” Third man, angel, alien or deity—all are sensed presences, so I call this the sensed-presence effect. In his gripping book, The Third Man Factor (Penguin, 2009), John Geiger documents the effect in mountain climbers, solo sailors and ultraendurance athletes. He lists conditions associated with it: monotony, darkness, barren landscapes, isolation, cold, injury, dehydration, hunger, fatigue and fear. I would add sleep deprivation; I have repeatedly experienced its effects and witnessed it in others during the 3,000-mile nonstop transcontinental bicycle Race Across America. Four-time winner Jure Robic, a Slovenian soldier, recounted to the New York Times that during one race he engaged in combat a gaggle of mailboxes he was convinced were enemy troops; another year he found himself being chased by a “howling band” of black-bearded horsemen: “Mujahedeen, shooting at me. So I ride faster.” © 2010 Scientific American

Keyword: Emotions
Link ID: 13942 - Posted: 06.24.2010

By NATALIE ANGIER I recently tried taking a couple of online personality tests, and I must say I was disappointed by the exercise. I was asked bland amorphisms like whether I was “someone who tends to find fault” with people (duh), is generally “friendly and agreeable” (see previous response), and always “does a thorough job” (can I just skip this question?). Nowhere were there any real challenges like the following: Let’s say you are very hungry, and you go over to your favorite food dish. Inside you see, in addition to the standard blend of peanuts and insect parts, a bright pink plastic frog. How long before you work up the nerve to eat your dinner anyway? Or: You have just been ushered into a room that is in every way familiar, except that somebody has put a scrap of old, brown carpet in the middle of the floor. Do you keep your distance from the novelty item, or do you rush over and start pecking at it? These and other vividly tangible gems are taken from the burgeoning field of animal personality research, the effort to understand why individual members of the same species can be so mulishly themselves, and so unlike one another on a wide variety of behavioral measures. Scientists studying animals from virtually every niche of the bestial kingdom have found evidence of distinctive personalities — bundled sets of behaviors, quirks, preferences and pet peeves that remain stable over time and across settings. They have found stylistic diversity in chimpanzees, monkeys, barnacle geese, farm minks, blue tits and great tits, bighorn sheep, dumpling squid, pumpkinseed sunfish, zebra finches, spotted hyenas, even spiders and water striders, to name but a few. They have identified hotheads and tiptoers, schmoozers and loners, divas, dullards and fearless explorers, and they have learned that animals, like us, often cling to the same personality for the bulk of their lives. The daredevil chicken of today is the one out crossing the road tomorrow. Copyright 2010 The New York Times Company

Keyword: Emotions; Evolution
Link ID: 13941 - Posted: 06.24.2010

By Lisa Grossman The part of the brain that’s used to decode a sentence depends on the grammatical structure of the language it’s communicated in, a new study suggests. Brain images showed that subtly different neural regions were activated when speakers of American Sign Language saw sentences that used two different kinds of grammar. The study, published online this week in Proceedings of the National Academy of Sciences, suggests neural structures that evolved for other cognitive tasks, like memory and analysis, may help humans flexibly use a variety of languages. “We’re using and adapting the machinery we already have in our brains,” says study coauthor Aaron Newman of Dalhousie University in Halifax, Canada. “Obviously we’re doing something different [from other animals], because we’re able to learn language. But it’s not because some little black box evolved specially in our brain that does only language, and nothing else.” Most spoken languages express relationships between the subject and object of a sentence — the “who did what to whom,” Newman says — in one of two ways. Some languages, like English, encode information in word order. “John gave flowers to Mary” means something different than “Mary gave flowers to John.” And “John flowers Mary to gave” doesn’t mean anything at all. © Society for Science & the Public 2000 - 2010

Keyword: Language
Link ID: 13940 - Posted: 06.24.2010

by David Robson AT EINSTEIN's autopsy in 1955, his brain was something of a disappointment: it turned out to be a tad smaller than the average Joe's. Indeed, later studies have suggested a minimal link between brain size and intelligence. It seems brain quality rather than quantity is key. One important factor seems to be how well our neurons can talk to each other. Martijn van den Heuvel, a neuroscientist at Utrecht University Medical Center in the Netherlands, found that smarter brains seem to have more efficient networks between neurons - in other words, it takes fewer steps to relay a message between different regions of the brain. That could explain about a third of the variation in a population's IQ, he says. Another key factor is the insulating fatty sheath encasing neuron fibres, which affects the speed of electrical signals. Paul Thompson at the University of California, Los Angeles, has found a correlation between IQ and the quality of the sheaths (The Journal of Neuroscience, vol 29, p 2212). We still don't know exactly how much genes contribute to intelligence, with various studies coming up with estimates ranging from 40 to 80 per cent. This wide range of estimates might have arisen because genes contribute more to IQ as we get older, according to a study published last year. By comparing the intelligence of 11,000 pairs of twins, Robert Plomin of King's College London found that at age 9, genes explain 40 per cent of the variation, but by 17 they account for roughly two-thirds (Molecular Psychiatry, DOI: 10.1038/mp.2009.55). © Copyright Reed Business Information Ltd.

Keyword: Intelligence; Genes & Behavior
Link ID: 13939 - Posted: 06.24.2010

The autism-spectrum disorders encompass a wide range of symptoms, from social awkwardness to a complete inability to interact and communicate. Here, six men and women speak about living with an autism-spectrum disorder. (Join the discussion here.) Copyright 2010 The New York Times Company

Keyword: Autism
Link ID: 13938 - Posted: 04.05.2010

By Rachel Ehrenberg You don’t need to lead a fly to water to make it drink. A new discovery by neuroscientists helps explain why. Researchers have illuminated the biochemical mechanism that fruit flies use to detect water in their environment. The finding may lead to a better understanding of how all cells control their water content, and perhaps to similar discoveries in people. Researchers report online in Nature April 4 that a protein known as PPK28 helps fruit flies taste water. The protein makes up a channel that spans the membrane of a water-sensing nerve cell in the feeding tube of Drosophila, the fruit fly. PPK28 is from a larger family of channel proteins that includes one mammals use to taste salt. But none had been pegged as a mediator of water flow into cells. It’s possible that related proteins have similar tasks in the cells of mammals, says Charles Bourque of the Centre for Research in Neuroscience at McGill University in Montreal, Canada, who was not involved in the work. Peter Cameron of the University of California, Berkeley and his colleagues identified the water-sensing role of PPK28 by comparing the genes of normal flies to a group whose taste cells had been transformed into touch sensors. The genetics pointed to PPK28 as a likely fly divining rod. When the researchers marked the protein with a fluorescent tag and gave the flies various solutions to drink, PPK28 lit up when the flies tasted water, revealing a “drink me” signal that was going right to their brains. © Society for Science & the Public 2000 - 2010

Keyword: Chemical Senses (Smell & Taste)
Link ID: 13937 - Posted: 06.24.2010

By OLIVIA JUDSON Males and females are different. This is so obvious that, at first, it hardly seems worth pointing out. But in fact, it is remarkable. It is also the cause of a profound sexual tension. The problem is, often, the pressures on males and females are not the same. In the fruit fly Drosophila melanogaster, for example, males must perform an elaborate song-and-dance routine to seduce each female; females, in contrast, must give off a certain smell to be attractive to a male. Females need to eat a high protein diet so as to be able to produce eggs; males can skimp on the proteins. male sage-grouseAssociated Press A strutting male sage-grouse. Among greater sage-grouse, Centrocercus urophasianus, females are smaller than males and have straw-colored feathers. Males have flamboyant feathers and strut and cavort and puff themselves up to seduce females. (The behavior of male and female sage grouse is well known; click here to see a male display.) Needless to say, in this species females do all the childcare: they choose a nest site, sit on the eggs, then feed and protect the chicks. In sum, the traits that make a “good” male are often different from those that make a “good” female. (Note: I’m only talking about “good” in evolutionary terms. That means a trait that improves your chance of having surviving offspring.) Since many of these traits have a genetic underpinning, male and female genes are thus being sculpted by different forces. Copyright 2010 The New York Times Company

Keyword: Evolution; Sexual Behavior
Link ID: 13936 - Posted: 06.24.2010

By JON MOOALLEM The Laysan albatross is a downy seabird with a seven-foot wingspan and a notched, pale yellow beak. Every November, a small colony of albatrosses assembles at a place called Kaena Point, overlooking the Pacific at the foot of a volcanic range, on the northwestern tip of Oahu, Hawaii. Each bird has spent the past six months in solitude, ranging over open water as far north as Alaska, and has come back to the breeding ground to reunite with its mate. Albatrosses can live to be 60 or 70 years old and typically mate with the same bird every year, for life. Their “divorce rate,” as biologists term it, is among the lowest of any bird. When I visited Kaena Point in November, the first birds were just returning, and they spent a lot of their time gliding and jackknifing in the wind a few feet overhead or plopped like cushions in the sand. There are about 120 breeding albatrosses in the colony, and gradually, each will arrive and feel out the crowd for the one other particular albatross it has been waiting to have sex with again. At any given moment in the days before Thanksgiving, some birds may be just turning up while others sit there killing time. It feels like an airport baggage-claim area. Once together, pairs will copulate and collaboratively incubate a single egg for 65 days. They take shifts: one bird has to sit at the nest while the other flaps off to fish and eat for weeks at a time. Couples preen each other’s feathers and engage in elaborate mating behaviors and displays. “Like when you’re in a couple,” Marlene Zuk, a biologist who has visited the colony, explained to me. “All those sickening things that couples do that gross out everyone else but the two people in the couple? . . . Birds have the same thing.” Copyright 2010 The New York Times Company

Keyword: Sexual Behavior
Link ID: 13935 - Posted: 06.24.2010

By Tina Hesman Saey When faced with a choice between carb loading and a protein-rich, Atkins-style diet, honeybees let their guts decide. Insulin signals from fat cells in the bees’ abdomens help determine whether they forage for high-protein pollen or sugar-filled nectar, a new study shows. The study, published April 1 in PLoS Genetics, is the first to manipulate insulin signals in honeybees and to show how changes in the signals influence behavior. Reducing the activity of the insulin receptor substrate, or IRS, gene caused bees to forage more for pollen than for nectar, report researchers led by Gro Amdam, a biologist at Arizona State University in Tempe and the Norwegian University of Life Sciences in Aas. The researchers showed that the gene, which is involved in sugar uptake by cells, regulates not just how nutrients are turned into energy but also the bees’ preferences for which foods to consume in the first place. Reducing the gene’s activity in fat cells affects the bees’ behavior even if the gene is functioning normally in the brain, Amdam’s group discovered. That suggests the gene causes fat cells to generate a chemical signal that tells the brain what kind of food to look for. “That’s something that I find quite remarkable,” says Thomas Flatt, a geneticist at the University of Veterinary Medicine in Vienna, Austria. “I don’t think many people have considered how insulin is affecting food choices, not just what happens after food has entered the body. The behavior dimension is new and interesting.” © Society for Science & the Public 2000 - 2010

Keyword: Obesity
Link ID: 13934 - Posted: 06.24.2010

By Katie Moisse More than 15 years after a genetic variant was shown to predispose its carriers to schizophrenia, scientists have finally uncovered how the chromosomal abnormality might cause symptoms of the brain disorder. By studying mice with a similar gene defect, the research team from Columbia University Medical Center linked abnormalities in behavior to a faulty connection between the hippocampus and the prefrontal cortex—two brain areas important for learning and memory. "We know that this genetic deficit predisposes us to schizophrenia, and now we have identified a clear pathophysiological mechanism of how [it] confers this risk…," Maria Karayiorgou, co-author on the study published April 1 in Nature and lead author on the 1994 publication identifying the genetic variant in Brain Research, said in a prepared statement. (Scientific American is part of Nature Publishing Group.) Thirty percent of people carrying the variant—a small deletion of genetic material on chromosome 22—will go on to develop the schizophrenia, making it "one of largest genetic risk factors" for the disease, according to senior author Joshua Gordon. The odds of someone in the general U.S. population developing the disorder are one in 100, but those odds jump to one in 10 for people with an affected first-degree relative, and one in three for people with a schizophrenic identical twin, highlighting the role of genes in the development of the disease. © 2010 Scientific American,

Keyword: Schizophrenia; Genes & Behavior
Link ID: 13933 - Posted: 06.24.2010

by MacGregor Campbell "THE leg wasn't bouncing all over the table, but there were substantial twitches," says Matthew Schiefer, a neural engineer at Case Western Reserve University in Cleveland, Ohio. Schiefer is describing an experiment in which pulses of electricity are used to control the muscles of an unconscious patient, as if they were a marionette. It represents the beginnings of a new generation of devices that he hopes will allow people with paralysed legs to regain control of their muscles and so be able to stand, or even walk again. His is one of a raft of gadgets being developed that plug into the network of nerves that normally relay commands from the spinal cord to the muscles, but fall silent when a spinal injury breaks the chain. New ways to connect wires to nerves (see diagram) allow artificial messages to be injected to selectively control muscles just as if the signal had originated in the brain. Limbs that might otherwise never again be controlled by their owners can be brought back to life. The potential of this approach was demonstrated in 2006 when a different Case Western team enabled someone who was paralysed from the waist down to watch their usually motionless knees straighten at the push of a button. With a little support they even stood for 2 minutes while signals injected into nerves in their thighs kept their knees straight. © Copyright Reed Business Information Ltd

Keyword: Regeneration
Link ID: 13932 - Posted: 06.24.2010

By GINA KOLATA Dr. Bastiaan R. Bloem of the Radboud University Nijmegen Medical Center in the Netherlands thought he had seen it all in his years of caring for patients with Parkinson’s disease. But the 58-year-old man who came to see him recently was a total surprise. A video from the Netherlands of a 58-year-old man with a 10-year history of Parkinson’s disease showed him freezing in his movements after a few steps. Yet he was able to ride a bicycle. The man had had Parkinson’s disease for 10 years, and it had progressed until he was severely affected. Parkinson’s, a neurological disorder in which some of the brain cells that control movement die, had made him unable to walk. He trembled and could walk only a few steps before falling. He froze in place, his feet feeling as if they were bolted to the floor. But the man told Dr. Bloem something amazing: he said he was a regular exerciser — a cyclist, in fact — something that should not be possible for patients at his stage of the disease, Dr. Bloem thought. “He said, ‘Just yesterday I rode my bicycle for 10 kilometers’ — six miles,” Dr. Bloem said. “He said he rides his bicycle for miles and miles every day.” “I said, ‘This cannot be,’ ” Dr. Bloem, a professor of neurology and medical director of the hospital’s Parkinson’s Center, recalled in a telephone interview. “This man has end-stage Parkinson’s disease. He is unable to walk.” Copyright 2010 The New York Times Company

Keyword: Parkinsons
Link ID: 13931 - Posted: 06.24.2010

By Carolyn Y. Johnson The pungent sting of wasabi, the searing pain of tear gas, and the watery eyes we get from chopping an onion are all triggered by an ancient chemical sensor that is found in everything from humans to mollusks and may hold the key to developing new kinds of insect repellents and pain medications. Research by Brandeis University scientists finds that the ability to detect noxious compounds comes from a biological pathway older than our sense of smell, emerging far in the evolutionary past, about half a billion years ago. “This chemical sense, as far as we can tell, appears to have been essentially unchanged,’’ said Paul Garrity, a biology professor at Brandeis and senior author of a paper published in the journal Nature this month. The sensor’s ubiquity and stability suggested it does something essential for the survival of animals, but what? For years, researchers had been interested in the sensor, a molecule called TRPA1 that is known to be involved in pain perception. It responds to chemicals that can damage tissue, such as ingredients in wasabi or cigarette smoke. Those chemicals are created by many plants to ward off predators that might chew on their leaves. Researchers interested in finding ways to dampen pain had studied the sensor, which occurs in humans. But they did not know why the chemical sensor existed in the first place. © 2010 NY Times Co.

Keyword: Chemical Senses (Smell & Taste); Emotions
Link ID: 13930 - Posted: 06.24.2010

By PATRICIA COHEN To illustrate what a growing number of literary scholars consider the most exciting area of new research, Lisa Zunshine, a professor of English at Kentucky University, refers to an episode from the TV series “Friends.” (Follow closely now; this is about the science of English.) Phoebe and Rachel plot to play a joke on Monica and Chandler after they learn the two are secretly dating. The couple discover the prank and try to turn the tables, but Phoebe realizes this turnabout and once again tries to outwit them. As Phoebe tells Rachel, “They don’t know that we know they know we know.” This layered process of figuring out what someone else is thinking — of mind reading — is both a common literary device and an essential survival skill. Why human beings are equipped with this capacity and what particular brain functions enable them to do it are questions that have occupied primarily cognitive psychologists. Now English professors and graduate students are asking them too. They say they’re convinced science not only offers unexpected insights into individual texts, but that it may help to answer fundamental questions about literature’s very existence: Why do we read fiction? Why do we care so passionately about nonexistent characters? What underlying mental processes are activated when we read? Ms. Zunshine, whose specialty is 18th-century British literature, became familiar with the work of evolutionary psychologists while she was a graduate student at Stanford in the 1990s. “I thought this could be the most exciting thing I could ever learn,” she said. Copyright 2010 The New York Times Company

Keyword: Language; Brain imaging
Link ID: 13929 - Posted: 06.24.2010

By Tina Hesman Saey Zebra finches have something to tweet about. The little songbirds’ genetic instruction book has just been deciphered. An international team of scientists announced the accomplishment in the April 1 Nature. Zebra finches are the first songbirds and the second bird, after the chicken, with a completely decoded genetic blueprint. Contained within the finch’s DNA could be clues to how songbirds learn vocal information and use songs in social situations, a model for human language and communication. Whales, dolphins, some bats and several other species of birds also learn vocally, but the mouse-sized zebra finch has become a model system for studying the process in the laboratory. Male zebra finches memorize their fathers’ songs and practice singing the song for a month or two. Once learned, a male’s song is his signature. Unlike other songbirds that can change their songs, he sings his for life. Discovering the molecular mechanisms behind how songbirds learn their songs could also help scientists better understand human communication disorders such as autism and stuttering, says David Clayton, a neurobiologist at the University of Illinois at Urbana-Champaign, who was one of the leaders of the study. Neuroscientists have studied zebra finches for years to learn which parts of the birds’ brains become active as the animals hear and learn new songs. The new genetic information will add molecular details to help scientists better understand vocal learning, says Allison Doupe, a neuroscientist and psychiatrist at the University of California, San Francisco. She was not involved in the new study, but says the genetic information is a welcome tool for researchers who study the finches. © Society for Science & the Public 2000 - 2010

Keyword: Animal Communication; Genes & Behavior
Link ID: 13928 - Posted: 06.24.2010

by Lauren Schenkman Birds do it, monkeys do it, humans do it-learning from the individuals around you is a crucial skill if you want to survive in a group. Scientists have thought that the ability to learn from others evolved in step with communal living. Now a study demonstrates an exception: A solitary reptile is an adept social learner. From the time young red-footed tortoises (Geochelone carbonaria) hatch in their native South American rainforests, they are alone. They grow up without parents or siblings, and adults rarely cross paths. If a head-bobbing display determines that a stranger is of the opposite sex, the two will mate perfunctorily-otherwise they just ignore each other. In a species so uninterested in social interactions, it's hard to see how the ability to learn from others could have evolved, says Anna Wilkinson, a cognitive biologist at the University of Vienna. But one day she scattered dandelions, a favorite snack, near a female tortoise named Wilhelmina, who began to eat. A second tortoise ignored a clump that had fallen near him and followed Wilhelmina to her clump instead. This made Wilkinson wonder whether the second tortoise had "learned that the dandelions were there" by observing where Wilhelmina was eating. So Wilkinson set out to test whether tortoises learned a navigation task better by watching other tortoises or on their own. She set up a v-shaped wire fence and placed a bowl containing a few tidbits of strawberry and mushroom inside the fence at the point of the "V". Then she set Wilhelmina outside the tip of the "V", with the treats on the other side of the fence. In 12 trials, Wilhelmina tried to force her way through the barrier but never tried to walk around. The same was true of three other control tortoises Wilkinson and her colleagues tested. "In later trials, they would ... go up the arm [of the "V"] and go to sleep," says Wilkinson. © 2010 American Association for the Advancement of Science.

Keyword: Learning & Memory
Link ID: 13927 - Posted: 06.24.2010