By Bruce Bower Indo-European languages range throughout Europe and South Asia and even into Iran, yet the roots of this widespread family of tongues have long been controversial. A new study adds support to the proposal that the language family expanded out of Anatolia — what’s now Turkey — between 8,000 and 9,500 years ago, as early farmers sought new land to cultivate. A team led by psychologist Quentin Atkinson of the University of Auckland in New Zealand came to that conclusion by using a mathematical method to calculate the most likely starting point and pattern of geographic spread for a large set of Indo-European languages. The new investigation, published in the Aug. 24 Science, rejects a decades-old idea that Kurgan warriors riding horses and driving chariots out of West Asia’s steppes 5,000 to 6,000 years ago triggered the rise of Indo-European speakers. “Our analysis finds decisive support for an Anatolian origin over a steppe origin of Indo-European languages,” Atkinson says. He and his colleagues generated likely family trees for Indo-European languages, much as geneticists use DNA from different individuals to reconstruct humankind’s genetic evolution. Many linguists, who compare various features of languages to establish their historical connections, consider Atkinson’s statistical approach unreliable (SN: 11/19/11, p. 22). © Society for Science & the Public 2000 - 2012

Keyword: Language; Aggression
Link ID: 17200 - Posted: 08.25.2012

By Susan Milius Black bears, which live relatively solitary lives as adults, show an ability to learn concepts, a new study finds. Dave Allen Photography/Shutterstock American black bears that take computerized tests by pawing, nose-bumping or licking a touch screen may rival great apes when it comes to learning concepts. Using three zoo bear siblings as classroom subjects, comparative cognitive psychologist Jennifer Vonk of Oakland University in Rochester, Mich., and her colleagues presented pairs of pictures to the bears on a rugged computer screen and gave them food treats for pawing the image from a certain category. To demonstrate learning a concept, bears had to figure out what kind of picture would earn a treat and then pick that kind of image from a new set. One challenge, picking the portrait of a black bear instead of an image of a person, could be mastered by relying on a mix of visual clues such as furriness or snout shape. But picking out all the animals from non-animals — cars or landscapes, for example — required finding more abstract connections among pictures that didn’t look much at all alike. At least one of the three bears showed some capacity at each of the five levels tested, Vonk and colleagues report in an upcoming Animal Behaviour. Bear behavior has been “very underappreciated,” says comparative ethologist Gordon Burghardt of the University of Tennessee at Knoxville. “They’re very smart and they have large brains.” They also live relatively solitary lives, which make them an important contrast to the mostly social animals tested for complex mental capacities to date. © Society for Science & the Public 2000 - 2012

Keyword: Intelligence; Aggression
Link ID: 17195 - Posted: 08.25.2012

by Hannah Krakauer Kanzi the bonobo continues to impress. Not content with learning sign language or making up "words" for things like banana or juice, he now seems capable of making stone tools on a par with the efforts of early humans. Eviatar Nevo of the University of Haifa in Israel and his colleagues sealed food inside a log to mimic marrow locked inside long bones, and watched Kanzi, a 30-year-old male bonobo chimp, try to extract it. While a companion bonobo attempted the problem a handful of times, and succeeded only by smashing the log on the ground, Kanzi took a longer and arguably more sophisticated approach. Both had been taught to knap flint flakes in the 1990s, holding a stone core in one hand and using another as a hammer. Kanzi used the tools he created to come at the log in a variety of ways: inserting sticks into seams in the log, throwing projectiles at it, and employing stone flints as choppers, drills, and scrapers. In the end, he got food out of 24 logs, while his companion managed just two. Perhaps most remarkable about the tools Kanzi created is their resemblance to early hominid tools. Both bonobos made and used tools to obtain food – either by extracting it from logs or by digging it out of the ground. But only Kanzi's met the criteria for both tool groups made by early Homo: wedges and choppers, and scrapers and drills. © Copyright Reed Business Information Ltd.

Keyword: Evolution; Aggression
Link ID: 17191 - Posted: 08.22.2012

By Jason G. Goldman The largest fish in the ocean is the whale shark (Rhincodon typus). This massive, migratory fish can grow up to twelve meters in length, but its enormous mouth is designed to eat the smallest of critters: plankton. While the biggest, the whale shark isn’t the only gigantic filter-feeding shark out there: the basking shark and the megamouth shark also sieve enormous amounts of the tiny organisms from the sea in order to survive. While scientists like Al Dove and Craig McClain (of Deep Sea News) are learning more and more about the basic biology and behavior of these magnificent creatures, other scientists are busy investigating their neuroanatomy. A few years ago, Kara E. Yopak and Lawrence R. Frank from the University of California in San Diego got their hands on two whale shark brains from an aquarium, and put them into an MRI scanner. But they weren’t just interested in imaging the brains of the whale sharks. What they wanted to know was how the organization of whale shark brains compared to the brains of other shark species for which scientists had previously obtained neuroanatomical data. Would the brains of two species be more similar if they shared a recent evolutionary ancestor, and were therefore more genetically related? Or would shark brains be more similar among species that shared a similar lifestyle, such as those that patrol the middle and surface of the water column (pelagic sharks, such as the great white, oceanic whitetip, blue, mako, and whale sharks) versus those that live along the sea floor (benthic sharks, such as the nurse and cat sharks). Or perhaps the brains of sharks would be grouped according to their habitat, such as those that live in coastal waters, around reefs, or in the open ocean. Maybe sharks brains ought to be grouped according to behavioral specialization, such as hunting methods. Answers to these questions could shed some important light on brain evolution, both in sharks as well as more generally. © 2012 Scientific American

Keyword: Evolution; Aggression
Link ID: 17180 - Posted: 08.18.2012

By Susan Milius COLLEGE PARK, Md. — A mantis shrimp, which has one of the most elaborate visual systems ever discovered, turns out to be pretty lousy at distinguishing one color from another. The puzzling underachievement may mean that the mantis shrimp brain perceives color in a way new to science, says Hanne Thoen of the University of Queensland in Brisbane, Australia. She presented results from her ongoing study August 6 at the 10th International Congress of Neuroethology. The stalked eyes of mantis shrimp species that live in shallow water can have up to 16 kinds of photoreceptor cells, 12 of which are specialized for different colors. People make do with four kinds, three of which pick up colors. Yet tests with pairs of increasingly similar colors found that the mantis shrimp Haptosquilla trispinosa flunks out when choices narrow to colors 15 nanometers apart in wavelength, Thoen said. At sweet spots in the color spectrum, people can distinguish between colors only 1 or 2 nanometers apart. “Hanne’s results are a bit of a shock to us,” says Thomas Cronin of the University of Maryland, Baltimore County, whose lab also studies mantis shrimp vision. Thoen tested the color vision of mantis shrimp by training them to scoot out of their burrows toward a pair of optical fibers and punch at the one glowing a particular color. As she narrowed the color gap between the two fibers, she could tell when the animals no longer discerned a difference. © Society for Science & the Public 2000 - 2012

Keyword: Vision; Aggression
Link ID: 17165 - Posted: 08.15.2012

By Bruce Bower An ancient finger bone recently landed a genetic sucker punch on scientists studying human evolution. DNA extracted from this tiny fossil, unearthed in Siberia’s Denisova Cave, unveiled a humanlike population that interbred with people in East Asia at least 44,000 years ago. Denisovans supplied nearly 5 percent of the genes of native groups now living in Australia, New Guinea and on several nearby islands. That molecular shocker followed a revelation that the genetic instruction books of people from Australia to the Americas contain a roughly 2.5 percent contribution from Neandertals, modern humans’ evolutionary cousins that died out around 30,000 years ago. Pulling the DNA shades up on ancient human dalliances with Neandertals and closely related Denisovans has sparked a scientific consensus that members of mobile human groups interbred with closely related populations in the Homo genus during the Stone Age. “The question is no longer ‘When did ancient populations such as Neandertals go extinct?’ but ‘What happened to those populations and to modern humans as a result of interbreeding?’ ” says anthropologist John Hawks of the University of Wisconsin–Madison. Clear signs of interbreeding have left archaeologists and other students of the Stone Age scrambling to revisit existing ideas about Homo sapiens’ evolutionary past. A dominant theory holding that humans evolved in Africa and left on neat one-way routes to Asia and Europe has to be revised. Instead, these ancient people must have followed a tangled web of paths taking them to other continents and sometimes reversing course. During these travels, humans encountered Neandertals, Denisovans and probably other humanlike populations that were already traipsing interconnected avenues through Asia and Europe. © Society for Science & the Public 2000 - 2012

Keyword: Evolution
Link ID: 17161 - Posted: 08.14.2012

ROBINS appear to have an eye for numbers, at least when it comes to choosing the biggest meal. "Discriminating between two large groups of objects that are close in number would be pretty exceptional for any animal or human, but that's exactly what the robins did," says Alexis Garland at Victoria University of Wellington in New Zealand. Garland let 36 wild North Island robins choose one of two wells after seeing different numbers of mealworms dropped en masse into each. Most picked the fuller well as long as the ratio was below 0.75 - correctly selecting, say, 64 over 32 worms. The mechanism at work here is called ratio-based representation and involves guessing which large group of items has the bigger bulk. The robins did even better when the worms were dropped into the wells one by one and covered so that the masses could not be compared: they managed a ratio of 0.88, albeit with a smaller number of worms. For the largest trial at this ratio - 14 versus 16 worms - most robins chose correctly (Animal Cognition, DOI: 10.1007/s10071-012-0537-3). Other animals tested like this have only managed to track about four items. Robins hide multiple food items in several places so it may be advantageous to distinguish more from less quickly, says Garland. © Copyright Reed Business Information Ltd.

Keyword: Intelligence; Aggression
Link ID: 17144 - Posted: 08.11.2012

By Stephanie Pappas Senior Writer Parrots can draw conclusions about where to find a food reward not only from clues as to its location, but also from the absence of clues — an ability previously only seen in humans and other apes. In a new study, researchers tested African Grey parrots on their reasoning abilities by shaking empty boxes and boxes filled with food so that the parrots could hear the snacks rattling around. To pick the box that would win them a treat, the parrots had to figure out that the sound indicated food and that a lack of sound from one box probably meant food in the other. It's a challenge that even human children can't reason through until about age 3. "It suggests that Grey parrots have some understanding of causality and that they can use this to reason about the world," study scientist Christian Schloegl, a researcher at the University of Vienna, told LiveScience. African Grey parrots are known to be clever, as are many other birds. In earlier studies with Grey parrots, researchers have shown them two opaque boxes, one full of food and one empty. When the parrots are shown that one box has no food in it, they almost always pick the second box in search of a treat. This could be because the parrots infer that if one box is empty, the other is likely full, Schloegl said. But researchers couldn't rule out that they were simply avoiding the empty box for some unknown reason. © 2012 NBCNews.com

Keyword: Intelligence; Aggression
Link ID: 17142 - Posted: 08.08.2012

By Michael Harré As humans, we aren't born with formidable armaments or defenses, nor are we the strongest, fastest, or biggest species, yet despite this we are amazingly successful. For a long time it was thought that this success was because our enlarged brains allows each of us to be smarter than our competitors: better at abstract thinking, better with tools and better at adapting our behavior to those of our prey and predators. But are these really the most significant skills our brains provide us with? Another possibility is that we are successful because we can form long-lasting relationships with many others in diverse and flexible ways, and that this, combined with our native intelligence, explains why homo sapiens came to dominate the planet. In every way from teaching our young to the industrial division of labour we are a massively co-operative species that relies on larger and more diverse networks of relationships than any other species. In 1992 British anthropologist Robin Dunbar published an article showing that, in primates, the ratio of the size of the neo-cortex to that of the rest of the brain consistently increases with increasing social group size. For example, the Tamarin monkey has a brain size ratio of about 2.3 and an average social group of size of about 5 members. On the other hand, a Macaque monkey has a brain size ratio of around 3.8 but a very large average group size of about 40 members. From this work Dunbar put forward what is now known as the “social brain hypothesis.” The relative size of the neo-cortex rose as social groups became larger in order to maintain the complex set of relationships necessary for stable co-existence. Most famously, Dunbar suggested that given the human brain ratio we have an expected social group size of around 150 people, about the size of what Dunbar called a “clan.” © 2012 Scientific American,

Keyword: Evolution
Link ID: 17141 - Posted: 08.08.2012

By Stephanie Pappas Senior Writer For women looking to pass on their genes, it pays to be short. For men, tall is the ideal. The result? An evolutionary tug-of-war in which neither gender reaches their perfect height. Those are the results of a new study published Aug. 7 in the journal Biology Letters. The research finds that an evolutionary battle of the sexes keeps the genders in an endless feedback loop of height variations across the generations. "We should not simply assume that when a trait is beneficial for one sex, that selection or evolution will necessarily favor this trait," study researcher Gert Stulp, a scientist at the University of Groningen in the Netherlands, told LiveScience in an email. In the same way, traits that harm one sex but not the other may not be "weeded out" by natural selection, Stulp said. "This may even hold for health-related traits, such that genetic underpinnings beneficial to the health of one sex may increase the susceptibility to disease in the other sex," he said. In modern western societies, studies have found that women who are on the short side tend to have more children. In contrast, average-height men do the best, reproductively speaking, outpacing short and tall men in number of children fathered, Stulp said. © 2012 NBCNews.com

Keyword: Sexual Behavior; Aggression
Link ID: 17140 - Posted: 08.08.2012

by Michael Marshall The relatively sophisticated brain of a songbird has been transplanted into the body of a distantly related, less intelligent species. The study could help us understand how brains develop, perhaps opening the way to treating some brain conditions. Since 2009, Chun-Chun Chen of Duke University in Durham, North Carolina, has performed over 100 brain transplants in birds. In her latest study she transferred the cells destined to become the forebrain of zebra finches (Taeniopygia guttata) into Japanese quail (Coturnix japonica) embryos, after removing the equivalent quail cells. After the transplants, Chen incubated the eggs for up to 16 days, before opening them to find that the transplanted cells had integrated into their hosts, forming the normal neural pathways. None of the chimeric embryos hatched, however, perhaps because their hybrid brains could not trigger breathing. Chen says she will try to crack the hatching problem by transplanting just half a zebra finch forebrain, leaving half the quail forebrain still in place. Researchers have been attempting such transplants for decades. In 1957, Petar Martinovitch of Yale University transplanted the heads of one set of chicken embryos to another (Proceedings of the National Academy of Sciences, vol 43, p 354). Few survived. © Copyright Reed Business Information Ltd.

Keyword: Development of the Brain; Aggression
Link ID: 17134 - Posted: 08.07.2012

by Will Ferguson Let's face it, child rearing isn't for everyone. Midnight diaper changes, a seriously compromised social life, and trading in the two-seater coupe for a mid-size sedan can be too much for some of us to handle. Readers who find themselves in this category might be reassured to know there's at least one other creature on the planet that is, in all likelihood, even more keen to shirk parental responsibility. The common cuckoo is notorious for pawning off its young on other birds, like the Eurasian Reed Warbler (Acrocephalus scirpaceus). Unfortunately for these more willing caregivers, the cuckoo is a ruthless parasite. Upon hatching, young cuckoos push their surrogate brothers and sisters from the nest, leaving the unsuspecting host with a single cuckoo chick rather than a brood of its own. For obvious reasons, reed warblers have never been happy with the arrangement. They will attack female cuckoos on sight, reducing the chance of their nest being targeted. However, the sly cuckoo has developed an innovative way to avoid hostilities. Female cuckoos have evolved two different guises to minimise the chance of being recognised and attacked by warblers. It's unusual for female birds of a single species to come in different colours, but the phenomenon is surprisingly common for female cuckoos. Some are brownish-red, while others have grey, hawk-like plumage that deters other birds from attacking them. © Copyright Reed Business Information Ltd.

Keyword: Sexual Behavior; Aggression
Link ID: 17127 - Posted: 08.06.2012

by Nicholas St. Fleur With their trumpet-like calls, elephants may seem like some of the loudest animals on Earth. But we can't hear most of the sounds they make. The creatures produce low-frequency noises between 1 to 20 Hertz, known as infrasounds, that help them keep in touch over distances as large as 10 kilometers. A new study reveals for the first time how elephants produce these low notes. Scientists first discovered that elephants made infrasounds in the 1980s. The head female in a herd may produce the noises to guide her group's movements, whereas a male who’s in a mating state called musth might use the calls to thwart competition from other males. Mother elephants even rely on infrasounds to keep tabs on a separated calf, exchanging "I'm here" calls with the wayward offspring in a fashion similar to a game of Marco Polo. These noises, which fall below the hearing range for humans, are often accompanied by strong rumbles with slightly higher frequencies that people can hear. By recording the rumbles and then speeding up the playback, the scientists can increase the frequency of the infrasounds, making them audible. Good vibrations. The vocal folds of the excised larynx vibrating according to the myoelastic-aerodynamic method. Researchers have speculated that the noises come from vibrations in the vocal folds of the elephant larynx. This could happen in two ways. In the first, called active muscular contraction (AMC), neural signals cause the muscles in the larynx to contract in a constant rhythm. Cats do this when they purr. The second possibility is known as the myoelastic-aerodynamic (MEAD) method, and it occurs when air flows through the vocal folds causing them to vibrate—this also happens when humans talk. © 2010 American Association for the Advancement of Science

Keyword: Hearing; Aggression
Link ID: 17125 - Posted: 08.04.2012

By Tina Hesman Saey Expeditions to Africa may have brought back evidence of a hitherto unknown branch in the human family tree. But this time the evidence wasn’t unearthed by digging in the dirt. It was found in the DNA of hunter-gatherer people living in Cameroon and Tanzania. Buried in the genetic blueprints of 15 people, researchers found the genetic signature of a sister species that branched off the human family tree at about the same time that Neandertals did. This lineage probably remained isolated from the one that produced modern humans for a long time, but its DNA jumped into the Homo sapiens gene pool through interbreeding with modern humans during the same era that other modern humans and Neandertals were mixing in the Middle East, researchers report in the August 3 Cell. The evidence for ancient interbreeding is surprisingly convincing, says Richard “Ed” Green, a genome biologist at the University of California, Santa Cruz. “There is a signal that demands explanation, and archaic admixture seems to be the most reasonable one at this point,” he says. Scientists have discovered that some people with ancestry outside Africa have DNA inherited from Neandertals or Denisovans, a mysterious group known only through DNA derived from a fossil finger bone found in a Siberian cave (SN: 6/5/10, p. 5; SN: 1/15/11, p.10). But those researchers had DNA from fossils to guide their research. This time, researchers led by Sarah Tishkoff at the University of Pennsylvania in Philadelphia didn’t have fossil DNA, or even fossils. © Society for Science & the Public 2000 - 2012

Keyword: Evolution
Link ID: 17112 - Posted: 08.01.2012

By JOHN NOBLE WILFORD In the widening search for the origins of modern human evolution, genes and fossils converge on Africa about 200,000 years ago as the where and when of the first skulls and bones that are strikingly similar to ours. So this appears to be the beginning of anatomically modern Homo sapiens. But evidence for the emergence of behaviorally modern humans is murkier — and controversial. Recent discoveries establish that the Homo sapiens groups who arrived in Europe some 45,000 years ago had already attained the self-awareness, creativity and technology of early modern people. Did this behavior come from Africa after gradual development, or was it an abrupt transition through some profound evolutionary transformation, perhaps caused by hard-to-prove changes in communication by language? Now, the two schools of thought are clashing again, over new research showing that occupants of Border Cave in southern Africa, who were ancestors of the San Bushmen hunter-gatherers in the area today, were already engaged in relatively modern behavior at least 44,000 years ago, twice as long ago as previously thought. Two teams of scientists reported these findings Monday in the journal Proceedings of the National Academy of Sciences. Since this early date for the San culture is close to when modern humans first left Africa and reached Europe, proponents of the abrupt-change hypothesis took the findings as good news. Richard G. Klein, a paleoanthropologist at Stanford University, said in an e-mail from South Africa that the new evidence “supports my view that fully modern hunter-gatherers emerged in Africa abruptly around 50,000 years ago, and I remain convinced that the behavior shift, or advance, underlies the successful expansion of modern Africans to Eurasia.” © 2012 The New York Times Company

Keyword: Evolution
Link ID: 17108 - Posted: 07.31.2012

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 Michael Marshall If you believe the Manic Street Preachers, there is no true love – just a finely-tuned jealousy. Once we've decided that another person is our special someone, we can become dangerously possessive and murderously unwilling to share them with others. Such all-consuming jealousy has a major downside: it's just so much effort. What if you can't be bothered? That seems to be how Hoffmann's two-toed sloths treat their sexual partners. Males do defend territories from rivals, but their slothful natures mean they aren't much good at holding onto females. Slow, so slow All sloths have a reputation for being lazy. This is sometimes exaggerated – they don't sleep much more than humans do – but basically correct. Sloths have unusually low metabolic rates and spend hours each day doing nothing. Hoffmann's two-toed sloth is a case in point. It spends the day hanging upside-down from branches high in trees, often hidden away within tangles of vines. During the night the sloths move around and feed, often for 7 or even 11 hours. But they're not exactly athletes, moving along branches at just 14 centimetres per second. They are also completely and utterly antisocial. Unless they're mating or caring for a youngster, you hardly ever see more than one sloth in a tree. © Copyright Reed Business Information Ltd.

Keyword: Sexual Behavior; Aggression
Link ID: 17084 - Posted: 07.24.2012

by Sarah C. P. Williams To escape a hungry wolf, a sheep doesn't have to outrun the wolf, just the other sheep in its flock. Many researchers think that such selfish behavior, not cooperation for the benefit of the whole crowd, shapes the movements of groups of animals. But the decades-old "selfish herd theory" has been hard to back up with data. Now, a detailed analysis of how a flock of sheep moves to avoid a sheepdog has found that the theory holds true. Each sheep heads to safety in the center of the flock, rather than running directly away from the dog. "It's really difficult to measure 2D spatial information on large animals in the wild," says biologist Theodore Stankowich of the University of Massachusetts, Amherst, who was not involved in the new work. "They've taken advantage of a unique opportunity to work with the sheep to answer these types of questions in a controlled environment." Studies on seals, crabs, and pigeons have shown that those animals seem to herd for selfish reasons, but the data have often been crude. Biologist Andrew King and colleagues at the Royal Veterinary College of the University of London attached GPS backpacks to 46 sheep and to a trained Australian Kelpie dog. When they released the dog to herd the sheep, they recorded the location of each animal every second. Then, they analyzed the data to determine what factors influenced each sheep's path. The movements of the sheep, the researchers reveal today online in Current Biology, could be best predicted by the center of the flock. Rather than run in a line away from the dog, scatter in all directions, or follow their nearest neighbors, the sheep all hurried toward the flock's center. The sheep began to converge when the dog was 70 meters away. Even as the flock as a whole moved, each sheep continuously competed to be as near the middle as possible. © 2010 American Association for the Advancement of Science.

Keyword: Aggression; Aggression
Link ID: 17079 - Posted: 07.24.2012

by Joseph Bennington-Castro Whether we realize it or not, most of us have a knee-jerk reaction when we see someone with a facial disfigurement, such as psoriasis, a cleft lip, or a birthmark. We may sit away from them on the bus, hesitate to shake their hand, or even give a barely masked look of revulsion. A new study suggests these disgust reactions stem from an ancient disease-avoidance system that normally prevents us from catching illnesses. Essentially, we treat facial disfigurements like infectious diseases. Psychologists have recently begun to uncover where disgust comes from, with some researchers believing the emotion is similar to fear. "Fear evolved to keep you away from large animals that want to eat you from the outside," says Valerie Curtis, a behavioral scientist at the London School of Hygiene and Tropical Medicine, who wasn't involved in the study. "Disgust evolved to keep you away from smaller animals that kill you from the inside." Our subconscious minds constantly scan the environment for signs of potential diseases, she says. If we see one, disgust kicks in and we avoid that object or person like the plague. But it seems our disease-avoidance system sometimes gets it wrong. Previous studies suggested these mistakes underlie the aversion people have to various disfigurements. For this to be true, our responses to people with facial disfigurements, which aren't contagious, would have to be the same as our responses to people with infectious diseases. © 2010 American Association for the Advancement of Science.

Keyword: Emotions; Aggression
Link ID: 17075 - Posted: 07.21.2012

Matt Kaplan Neanderthals have long been viewed as meat-eaters. The vision of them as inflexible carnivores has even been used to suggest that they went extinct around 25,000 years ago as a result of food scarcity, whereas omnivorous humans were able to survive. But evidence is mounting that plants were important to Neanderthal diets — and now a study reveals that those plants were roasted, and may have been used medicinally. The finding comes from the El Sidrón Cave in northern Spain, where the roughly 50,000-year-old skeletal remains of at least 13 Neanderthals (Homo neanderthalensis) have been discovered. Many of these individuals had calcified layers of plaque on their teeth. Karen Hardy, an anthropologist at the Autonomous University of Barcelona in Spain, wondered whether it might be possible to use this plaque to take a closer look at the Neanderthal menu. Using plaque to work out the diets of ancient animals is not entirely new, but Hardy has gone further by looking for organic compounds in the plaque. To do this she and a team including Stephen Buckley, an archaeological chemist at the University of York, UK, used gas chromatography and mass spectrometry to analyse the plaque collected from ten teeth belonging to five Neanderthal individuals from the cave. The plaque contained a range of carbohydrates and starch granules, hinting that the Neanderthals had consumed a variety of plant species. By contrast, there were few lipids or proteins from meat. © 2012 Nature Publishing Group

Keyword: Evolution
Link ID: 17067 - Posted: 07.19.2012