By STEPH YIN Despite being just the size of a rice grain, robber flies, which live all over the world, are champion predators. In field experiments, they can detect targets the size of sand grains from nearly two feet away — 100 times the fly’s body length — and intercept them in under half a second. What’s more, they never miss their mark. A team led by scientists at the University of Cambridge has started to unveil the secrets to the robber fly’s prowess. In a study published Thursday in Current Biology, the team outlined the mechanics of the fly’s pursuit, from its impressive eye anatomy to how it makes a successful catch every time. Notably, the researchers observed a behavior never before described in a flying animal: About 30 centimeters from its prey, the insect slows, turns slightly and brings itself in for a close catch. “This ‘lock-on’ phase and change in behavior during a flight is quite remarkable,” said Sam Fabian, a graduate student at Cambridge and an author of the study. “We would actually expect them to do something very simple — just accelerate and hit the target.” The scientists surveyed robber flies in the field using a “fly teaser,” which consisted of beads on a rapidly moving fishing line controlled by a motor. As the flies charged at the bait, the researchers captured their movements using high-speed cameras. At the start of the robber fly’s conquest, it sits on a perch and scans the sky for passing prey. When it glimpses a potential meal, it takes flight, maintaining a steady angle between itself and its target. This proactive strategy, using a “constant bearing angle,” is also employed by fish, bats and sailors, Mr. Fabian said. © 2017 The New York Times Company

Keyword: Vision
Link ID: 23346 - Posted: 03.11.2017

By Diana Kwon Deep in the Amazon rainforests of Bolivia live the Tsimane’, a tribe that has remained relatively untouched by Western civilization. Tsimane’ people possess a unique characteristic: they do not cringe at musical tones that sound discordant to Western ears. The vast majority of Westerners prefer consonant chords to dissonant ones, based on the intervals between the musical notes that compose the chords. One particularly notable example of this is the Devil’s Interval, or flatted fifth, which received its name in the Middle Ages because the sound it produced was deemed so unpleasant that people associated it with sinister forces. The flatted fifth later became a staple of numerous jazz, blues, and rock-and-roll songs. Over the years, scientists have gathered compelling evidence to suggest that an aversion to dissonance is innate. In 1996, in a letter to Nature, Harvard psychologists, Marcel Zentner and Jerome Kagan, reported on a study suggesting that four-month-old infants preferred consonant intervals to dissonant ones. Researchers subsequently replicated these results: one lab discovered the same effect in two-month-olds and another in two-day-old infants of both deaf and hearing parents. Some scientists even found these preferences in certain animals, such as young chimpanzees and baby chickens. “Of course the ambiguity is [that] even young infants have quite a bit of exposure to typical Western music,” says Josh McDermott, a researcher who studies auditory cognition at MIT. “So the counter-argument is that they get early exposure, and that shapes their preference.” © 1986-2017 The Scientist

Keyword: Hearing; Emotions
Link ID: 23345 - Posted: 03.11.2017

By Aylin Woodward Noise is everywhere, but that’s OK. Your brain can still keep track of a conversation in the face of revving motorcycles, noisy cocktail parties or screaming children – in part by predicting what’s coming next and filling in any blanks. New data suggests that these insertions are processed as if the brain had really heard the parts of the word that are missing. “The brain has evolved a way to overcome interruptions that happen in the real world,” says Matthew Leonard at the University of California, San Francisco. We’ve known since the 1970s that the brain can “fill in” inaudible sections of speech, but understanding how it achieves this phenomenon – termed perceptual restoration – has been difficult. To investigate, Leonard’s team played volunteers words that were partially obscured or inaudible to see how their brains responded. The experiment involved people who already had hundreds of electrodes implanted into their brain to monitor their epilepsy. These electrodes detect seizures, but can also be used to record other types of brain activity. The team played the volunteers recordings of a word that could either be “faster” or “factor”, with the middle sound replaced by noise. Data from the electrodes showed that their brains responded as if they had actually heard the missing “s” or “c” sound. © Copyright Reed Business Information Ltd.

Keyword: Hearing; Attention
Link ID: 23344 - Posted: 03.11.2017

By JESS BIDGOOD SALEM, Mass. — A few years ago, Bevil Conway, then a neuroscientist at Wellesley College, got an interesting request: Could he give a lecture to the curators and other staff at the Peabody Essex Museum, the art and culture museum here? So Mr. Conway gathered his slides and started from the beginning, teaching the basics of neuroscience — “How neurons work, how neurons talk to each other, issues of evolutionary biology,” Mr. Conway said — to people who run an institution best known for its venerable collections of maritime and Asian art. It was an early step in what has become a galvanizing mission for the museum’s director, Dan L. Monroe: harnessing the lessons of brain science to make the museum more engaging as attendance is falling around the country. “If one’s committed to creating more meaningful and impactful art experiences, it seems a good idea to have a better idea about how our brains work,” he said. “That was the original line of thinking that started us down this path.” The museum, known as P.E.M., has been looking at neuroscience to incorporate its lessons into exhibitions ever since. In an effort to build shows that engage the brain, it has tried breaking up exhibition spaces into smaller pieces; posting questions and quotes on the wall, instead of relying only on explanatory wall text; and experimenting with elements like smell and sound in visual exhibitions. And those efforts are about to increase. The museum recently received a $130,000 grant from the Barr Foundation, a Boston-based philanthropic organization, to bring a neuroscience researcher on staff, add three neuroscientists to the museum as advisers and publish a guide that will help other museums incorporate neuroscience into their exhibition planning. “A lot of what we’re seeing in museums right now is the interpretation of pieces, or artwork,” said E. San San Wong, a senior program officer with the foundation. “What this is looking at is: How do we more actively engage people with art, in multiple senses?” © 2017 The New York Times Company

Keyword: Vision; Emotions
Link ID: 23343 - Posted: 03.11.2017

Many epilepsy patients in Australia are turning to medicinal cannabis to manage their seizures, a survey has shown. The nationwide survey found 14% of people with epilepsy had used cannabis products to manage the condition. Of those, 90% of adults and 71% of children with epilepsy, according to their parents, reported success in managing seizures. GW Pharmaceuticals doubles in value after cannabis drug success in epilepsy trial Read more Published in the journal Epilepsy & Behaviour, the Epilepsy Action Australia study, in partnership with the Lambert Initiative at the University of Sydney, surveyed 976 respondents to examine cannabis use in people with epilepsy, reasons for use and any perceived benefits self-reported by consumers. The main reason given for trying cannabis products was to seek a treatment with “more favourable” side-effects compared with standard antiepileptic drugs. The lead author of the study, Anastatsia Suraeve from the Lambert Initiative, said researchers had gained further insight into the reasons that influence use. “Despite the limitations of a retrospective online survey, we cannot ignore that a significant proportion of adults and children with epilepsy are using cannabis-based products in Australia, and many are self-reporting considerable benefits to their condition,” Suraeve said. “More systematic clinical studies are urgently needed to help us better understand the role of cannabinoids in epilepsy,” she said. © 2017 Guardian News and Media Limited

Keyword: Epilepsy; Drug Abuse
Link ID: 23342 - Posted: 03.11.2017

Susan Milius Catch sight of someone scratching and out of nowhere comes an itch, too. Now, it turns out mice suffer the same strange phenomenon. Tests with mice that watched itchy neighbors, or even just videos of scratching mice, provide the first clear evidence of contagious scratching spreading mouse-to-mouse, says neuroscientist Zhou-Feng Chen of Washington University School of Medicine in St. Louis. The quirk opens new possibilities for exploring the neuroscience behind the spread of contagious behaviors. For the ghostly itch, experiments trace scratching to a peptide nicknamed GRP and areas of the mouse brain better known for keeping the beat of circadian rhythms, Chen and colleagues found. They report the results in the March 10 Science. In discovering this, “there were lots of surprises,” Chen says. One was that mice, nocturnal animals that mostly sniff and whisker-brush their way through the dark, would be sensitive to the sight of another mouse scratching. Yet Chen had his own irresistible itch to test the “crazy idea,” he says. Researchers housed mice that didn’t scratch any more than normal within sight of mice that flicked and thumped their paws frequently at itchy skin. Videos recorded instances of normal mice looking at an itch-prone mouse mid-scratch and, shortly after, scratching themselves. In comparison, mice with not-very-itchy neighbors looked at those neighbors at about the same frequency but rarely scratched immediately afterward. |© Society for Science & the Public 2000 - 2017.

Keyword: Pain & Touch; Learning & Memory
Link ID: 23341 - Posted: 03.10.2017

By Abby Olena Researchers have shown that a hormone secreted by bone, called lipocalin 2 (LCN2), suppresses appetite in mice. The results, published today (March 8) in Nature, suggest that LCN2 crosses the rodents’ blood-brain barrier and binds a receptor in the hypothalamus. The team also found a link between body weight and LCN2 levels in people with type 2 diabetes. The authors “have identified a protein that’s secreted from bone that has a pretty significant impact on feeding behavior,” Lora Heisler of the University of Aberdeen in Scotland, who did not participate in the work, told The Scientist. “And the fact that they found that some supporting evidence in humans is really exciting.” “We have found a new role for bone as an endocrine organ, and that is its ability to regulate appetite,” said study coauthor Stavroula Kousteni of Columbia University in New York City. Scientists had previously identified LCN2 as a protein expressed in fat cells, but Kousteni and colleagues showed that it is enriched 10-fold in osteoblasts. When they generated mice without LCN2 in their osteoblasts, levels of the circulating hormone dropped 67 percent. These mice ate more than control animals and showed increases in fat mass and body weight. When the authors injected LCN2 into wild-type or obese mice, the rodents ate less food. The treated animals showed decreases in body weight, fat mass, and weight gain. LCN2 injections also led to increases in insulin levels and glucose tolerance, the scientists showed. © 1986-2017 The Scientist

Keyword: Obesity; Hormones & Behavior
Link ID: 23340 - Posted: 03.10.2017

By Andy Coghlan Tiny particles secreted in response to head injury in the brains of mice could help explain how inflammation spreads and ultimately boosts the risk of developing dementia. Head injuries are increasingly being linked to cognitive problems and degenerative brain disease in later life. Mysterious particles a micrometre in diameter have previously been found in the spinal fluid of people with traumatic brain injury, but their function has remained unknown. Now Alan Faden at the University of Maryland School of Medicine in Baltimore and his colleagues have discovered that activated immune cells called microglia secrete such microparticles in response to brain injury, and they seem to spread inflammation well beyond the injury site itself. They can even cause brain inflammation when injected into uninjured animals. The particles have receptors that latch onto cells, and are packed with chemicals such as interleukins, which trigger inflammation, and fragments of RNA capable of switching whole suites of genes on or off. When Faden injured the brains of sedated mice, the microparticles spread well beyond the site of damage. Further experiments on cultured microglial cells revealed that the microparticles activate resting microglia, making them capable of triggering further inflammation themselves. © Copyright Reed Business Information Ltd.

Keyword: Brain Injury/Concussion; Glia
Link ID: 23339 - Posted: 03.10.2017

Researchers at Vanderbilt University in Nashville, Tennessee, have discovered that in zebrafish, decreased levels of the neurotransmitter gamma-aminobutyric acid (GABA) cue the retina, the light-sensing tissue in the back of the eye, to produce stem cells. The finding sheds light on how the zebrafish regenerates its retina after injury and informs efforts to restore vision in people who are blind. The research was funded by the National Eye Institute (NEI) and appears online today in Stem Cell Reports. NEI is part of the National Institutes of Health. “This work opens up new ideas for therapies for blinding diseases and has implications for the broader field of regenerative medicine,” said Tom Greenwell, Ph.D., NEI program officer for retinal neuroscience. For years, vision scientists have studied zebrafish to understand their retinal regenerative capacity. Zebrafish easily recover from retinal injuries that would permanently blind a person. Early studies in zebrafish led to the idea that dying retinal cells release signals that trigger support cells in the retinal called Muller glia to dedifferentiate — return to a stem-like state — and proliferate. However, recent studies in the mouse brain and pancreas suggest GABA, a well-characterized neurotransmitter, might also play an important role in regeneration distinct from its role in communicating local signals from one neuron to the next. Scientists studying a part of the brain called the hippocampus found that GABA levels regulate the activity of neural stem cells. When GABA levels are high, the stem cells stay quiet, and if GABA levels decrease, then the stem cells start to divide, explained James Patton, Ph.D., Stevenson Professor of Biological Sciences at Vanderbilt and senior author of the new study in zebrafish retina. A similar phenomenon was reported in mouse pancreas.

Keyword: Development of the Brain; Vision
Link ID: 23338 - Posted: 03.10.2017

By Torah Kachur, A simple, non-invasive, non-medicinal, safe and cheap way to get a better night's sleep is to play some pink noise, according to a study published on Wednesday in the journal Frontiers in Human Neuroscience. Pink noise has more lower octaves than typical white noise and is hardly soothing. For example, it can be one-second pulses of the sound of a rushing waterfall. The short pieces of quick, quiet sounds would be really annoying if you were trying to fall asleep. But the pink noise isn't trying to get you to fall asleep; it's trying to keep you in a very deep sleep where you have slow brainwaves. This is one of our deepest forms of sleep and, in particular, seems to decline in aging adults. "When you play the pulses at particular times during deep sleep, it actually leads to an enhancement of the electrical signal. So it leads to essentially more of a synchronization of the neurons," said Nelly Papalambros, a PhD student at Northwestern University and the first author on the work. The pulses are timed to coincide with your entry into slow wave sleep. They sound to the same beat as your brainwaves, and they seem to increase the effectiveness of your very valuable and very elusive deep sleep. That slow wave sleep is critical for memory consolidation or, basically, your ability to incorporate new material learned that day with old material and memories. ©2017 CBC/Radio-Canada.

Keyword: Sleep; Learning & Memory
Link ID: 23337 - Posted: 03.10.2017

If I was the late Andy Rooney, I’d say “You know what really bothers me? When science shows some facts about nature, and then someone rejects those facts because they’re inconvenient or uncomfortable for their ideology.” Indeed, when people ignore such inconvenient truths, it not only makes their cause look bad, but can produce palpable harm. Case in point: the damage that the Russian charlatan-agronomist Lysenko did to Soviet agriculture under Stalin. Rejecting both natural selection and modern genetics, Lysenko made all sorts of wild promises about improving Soviet agriculture based on bogus treatment of plants that would supposedly change their genetics. It not only didn’t work, failing to relieve Russia of its chronic famines, but Lyesnko’s Stalin-supported resistance to modern (“Western”) genetics led to the imprisonment and even the execution of really good geneticists and agronomists like Niklolia Vavilov. The ideological embrace of an unevidenced but politically amenable view of science set back Russian genetics for decades. Other cases in point: the denial of evolution by creationists, and of anthropogenic global warming by conservatives. I needn’t belabor these. But the opposition to research on group and sex differences continues. One of its big exponents is the author Cordelia Fine, who has written two books with the explicit aim of showing that there are no reliably accepted evolved and biological differences in behavior between men and women. I read her first book, Delusions of Gender, and found it a mixed bag: some of her targets did indeed do bad science, and she properly called them out; but the book was also tendentious, and wasn’t objective about other studies. I’m now about to read her second book, Testosterone Rex: Myths of Sex, Science, and Society. Judging from the reviews, which have been positive, it’s just as much a polemic as the first book, and has an ideological aim.

Keyword: Sexual Behavior; Evolution
Link ID: 23336 - Posted: 03.10.2017

By Meredith Wadman The U.S. Fish and Wildlife Service (FWS) is considering repealing a rule that exempts captive members of 11 threatened primate species from protection under the federal Endangered Species Act (ESA). If the agency approves a repeal, the captive animals would be designated as threatened, like their wild counterparts, and researchers would need to apply for permits for experiments. To be approved, studies would have to be aimed at species survival and recovery. A rule change would affect biomedical researchers who work with several hundred captive Japanese macaques housed in Oregon. People for the Ethical Treatment of Animals (PETA), a Norfolk, Virginia–based animal rights organization, petitioned FWS this past January, asking it to extend ESA protections to captive members of the 11 species housed in research labs, zoos, and held as pets. For obscure reasons, a “special rule” exempted these captive populations from ESA protection in 1976. Among the 11 species, the Japanese macaque (Macaca fuscata) appears to be the only one regularly used in U.S. research. A troop of roughly 300 resides at the Oregon National Primate Research Center in Hillsboro. That is where the main impact of a successful PETA petition would be felt by scientists. “The importance of protecting endangered animals can’t be minimized,” says Jared Goodman, the director of animal law at the PETA Foundation in Los Angeles, California. “These animals are not listed lightly [under the Endangered Species Act],” he adds. “And the agencies until now have unlawfully provided differential treatment to animals in captivity who are similarly threatened.” © 2017 American Association for the Advancement of Science.

Keyword: Animal Rights
Link ID: 23335 - Posted: 03.10.2017

There has been much gnashing of teeth in the science-journalism community this week, with the release of an infographic that claims to rate the best and worst sites for scientific news. According to the American Council on Science and Health, which helped to prepare the ranking, the field is in a shoddy state. “If journalism as a whole is bad (and it is),” says the council, “science journalism is even worse. Not only is it susceptible to the same sorts of biases that afflict regular journalism, but it is uniquely vulnerable to outrageous sensationalism”. News aggregator RealClearScience, which also worked on the analysis, goes further: “Much of science reporting is a morass of ideologically driven junk science, hyped research, or thick, technical jargon that almost no one can understand”. How — without bias or outrageous sensationalism, of course — do they judge the newspapers and magazines that emerge from this sludge? Simple: they rank each by how evidence-based and compelling they subjectively judge its content to be. Modesty (almost) prevents us from naming the publication graded highest on both (okay, it’s Nature), but some names are lower than they would like. Big hitters including The New York Times, The Washington Post and The Guardian score relatively poorly. It’s a curious exercise, and one that fails to satisfy on any level. It is, of course, flattering to be judged as producing compelling content. But one audience’s compelling is another’s snoozefest, so it seems strikingly unfair to directly compare publications that serve readers with such different interests as, say, The Economist and Chemistry World. It is equally unfair to damn all who work on a publication because of some stories that do not meet the grade. (This is especially pertinent now that online offerings spread the brand and the content so much thinner.) © 2017 Macmillan Publishers Limited

Keyword: Miscellaneous
Link ID: 23334 - Posted: 03.09.2017

Mo Costandi To many of us, having to memorize a long list of items feels like a chore. But for others, it is more like a sport. Every year, hundreds of these ‘memory athletes’ compete with one another in the World Memory Championships, memorising hundreds of words, numbers, or other pieces of information within minutes. The current world champion is Alex Mullen, who beat his competitors by memorizing a string of more than 550 digits in under 5 minutes. You may think that such prodigious mental feats are linked to having an unusual brain, or to being extraordinarily clever. But they are not. New research published in the journal Neuron shows that you, too, can be a super memorizer with just six weeks of intensive mnemonic training, and also reveals the long-lasting changes to brain structure and function that occur as a result of such training. The Homer Simpson effect: forgetting to remember Read more Martin Dresler of Radboud University in the Netherlands and his colleagues recruited 23 memory athletes, all of whom are currently in the top 50 of the memory sports world rankings, and a group of control participants, who had no previous experience of memory training, and who were carefully selected to match the group of champions in age, sex, and IQ. © 2017 Guardian News and Media Limited

Keyword: Learning & Memory
Link ID: 23333 - Posted: 03.09.2017

By Catherine Offord Getting to Santa María, Bolivia, is no easy feat. Home to a farming and foraging society, the village is located deep in the Amazon rainforest and is accessible only by river. The area lacks electricity and running water, and the Tsimane’ people who live there make contact with the outside world only occasionally, during trips to neighboring towns. But for auditory researcher Josh McDermott, this remoteness was central to the community’s scientific appeal. In 2015, the MIT scientist loaded a laptop, headphones, and a gasoline generator into a canoe and pushed off from the Amazonian town of San Borja, some 50 kilometers downriver from Santa María. Together with collaborator Ricardo Godoy, an anthropologist at Brandeis University, McDermott planned to carry out experiments to test whether the Tsimane’ could discern certain combinations of musical tones, and whether they preferred some over others. The pair wanted to address a long-standing question in music research: Are the features of musical perception seen across cultures innate, or do similarities in preferences observed around the world mirror the spread of Western culture and its (much-better-studied) music? “Particular musical intervals are used in Western music and in other cultures,” McDermott says. “They don’t appear to be random—some are used more commonly than others. The question is: What’s the explanation for that?” © 1986-2017 The Scientist

Keyword: Hearing
Link ID: 23332 - Posted: 03.09.2017

By Colin Barras What a difference 1000 kilometres make. Neanderthals living in prehistoric Belgium enjoyed their meat – but the Neanderthals who lived in what is now northern Spain seem to have survived on an almost exclusively vegetarian diet. This is according to new DNA analysis that also suggests sick Neanderthals could self-medicate with naturally occurring painkillers and antibiotics, and that they shared mouth microbiomes with humans – perhaps exchanged by kissing. Neanderthals didn’t clean their teeth particularly well – which is lucky for scientific investigators. Over time, plaque built up into a hard substance called dental calculus, which still clings to the ancient teeth even after tens of thousands of years. Researchers have already identified tiny food fragments in ancient dental calculus to get an insight into the diets of prehistoric hominins. Now Laura Weyrich at the University of Adelaide, Australia, and her colleagues have shown that dental calculus also carries ancient DNA that can reveal both what Neanderthals ate and which bacteria lived in their mouths. The team focused on three Neanderthals – two 48,000-year-old specimens from a site called El Sidrón in Spain and a 39,000-year-old specimen from a site called Spy in Belgium. The results suggested that the Spy Neanderthal often dined on woolly rhinoceros, sheep and mushrooms – but no plants. The El Sidrón Neanderthals ate more meagre fare: moss, bark and mushrooms – and, apparently, no meat. © Copyright Reed Business Information Ltd.

Keyword: Evolution; Pain & Touch
Link ID: 23331 - Posted: 03.09.2017

By Joshua A. Krisch Alcian blue-stained skateUCSF/JULIUS LABSharks, rays, and skates can detect minute fluctuations in electric fields—signals as subtle as a small fish breathing within the vicinity—and rely on specialized electrosensory cells to navigate, and hunt for prey hidden in the sand. But how these elasmobranch fish separate signal from noise has long baffled scientists. In an environment full of tiny electrical impulses, how does the skate home in on prey? See “Sensory Biology Around the Animal Kingdom” In a study published this week (March 6) in Nature, researchers at the University of California, San Francisco (UCSF), have analyzed the electrosensory cells of the little skate (Leucoraja erinacea). They found that voltage-gated calcium channels within these cells appear to work in concert with calcium-activated potassium channels, both specifically tuned in the little skate to pick up on weak electrical signals. “We have elucidated a molecular basis for electrosensation, at least in the little skate, which accounts for this unusual and highly sensitive mechanism for detecting electrical fields,” said coauthor Nicholas Bellono, a postdoc at USCF. “How general it is, we don’t know. But this is really the first instance in which we’ve been able to drill down and ask what molecules could be involved in this kind of system.” © 1986-2017 The Scientist

Keyword: Pain & Touch
Link ID: 23330 - Posted: 03.09.2017

By Jackie Snow Last month, Facebook announced software that could simply look at a photo and tell, for example, whether it was a picture of a cat or a dog. A related program identifies cancerous skin lesions as well as trained dermatologists can. Both technologies are based on neural networks, sophisticated computer algorithms at the cutting edge of artificial intelligence (AI)—but even their developers aren’t sure exactly how they work. Now, researchers have found a way to "look" at neural networks in action and see how they draw conclusions. Neural networks, also called neural nets, are loosely based on the brain’s use of layers of neurons working together. Like the human brain, they aren't hard-wired to produce a specific result—they “learn” on training sets of data, making and reinforcing connections between multiple inputs. A neural net might have a layer of neurons that look at pixels and a layer that looks at edges, like the outline of a person against a background. After being trained on thousands or millions of data points, a neural network algorithm will come up with its own rules on how to process new data. But it's unclear what the algorithm is using from those data to come to its conclusions. “Neural nets are fascinating mathematical models,” says Wojciech Samek, a researcher at Fraunhofer Institute for Telecommunications at the Heinrich Hertz Institute in Berlin. “They outperform classical methods in many fields, but are often used in a black box manner.” © 2017 American Association for the Advancement of Science.

Keyword: Robotics; Learning & Memory
Link ID: 23329 - Posted: 03.08.2017

By Andy Coghlan In primates such as humans, living in cooperative societies usually means having bigger brains — with brainpower needed to navigate complex social situations. But surprisingly, in birds the opposite may be true. Group-living woodpecker species have been found to have smaller brains than solitary ones. Cooperative societies might in fact enable birds to jettison all that brainpower otherwise needed on their own to constantly out-think, outfox and outcompete wily rivals, say researchers. Socialism in birds may therefore mean the individuals can afford to get dumber. The results are based on a comparison of brain sizes in 61 woodpecker species. The eight group-living species identified typically had brains that were roughly 30 per cent smaller than solitary and pair-living ones. “It’s a pretty big effect,” says lead researcher Richard Byrne at the University of St Andrews in the UK. Byrne’s explanation is that a solitary life is more taxing on the woodpecker brain than for those in cooperative groups, in which a kind of group-wide “social brain” takes the strain off individuals when a challenge arises. Group-living acorn woodpeckers in North America, for example, are well known for creating collective “granaries” of acorns by jamming them into crevices accessible to the whole group during hard times. © Copyright Reed Business Information Ltd.

Keyword: Evolution
Link ID: 23328 - Posted: 03.08.2017

By Lindzi Wessel You may have seen the ads: Just spray a bit of human pheromone on your skin, and you’re guaranteed to land a date. Scientists have long debated whether humans secrete chemicals that alter the behavior of other people. A new study throws more cold water on the idea, finding that two pheromones that proponents have long contended affect human attraction to each other have no such impact on the opposite sex—and indeed experts are divided about whether human pheromones even exist. The study, published today in Royal Society Open Science, asked heterosexual participants to rate opposite-sex faces on attractiveness while being exposed to two steroids that are putative human pheromones. One is androstadienone (AND), found in male sweat and semen, whereas the second, estratetraenol (EST), is in women’s urine. Researchers also asked participants to judge gender-ambiguous, or “neutral,” faces, created by merging images of men and women together. The authors reasoned that if the steroids were pheromones, female volunteers given AND would see gender-neutral faces as male, and male volunteers given EST would see gender-neutral faces as female. They also theorized that the steroids corresponding to the opposite sex would lead the volunteers to rate opposite sex faces as more attractive. That didn’t happen. The researchers found no effects of the steroids on any behaviors and concluded that the label of “putative human pheromone” for AND and EST should be dropped. “I’ve convinced myself that AND and EST are not worth pursuing,” says the study’s lead author, Leigh Simmons, an evolutionary biologist at the University of Western Australia in Crawley. © 2017 American Association for the Advancement of Science.

Keyword: Chemical Senses (Smell & Taste); Hormones & Behavior
Link ID: 23327 - Posted: 03.08.2017