thinker_jeff

Here is the classic conclusion for this topic. Mindless Collectives Better at Rational Decision-Making Than Brainy Individuals Humans often make irrational choices when faced with challenging decisions. Ant colonies, however, can make perfectly rational selections when confronted by tough dilemmas. This isn't because lone ants are especially knowledgeablethey're not. Instead, when ants are grouped together, a kind of "wisdom of the crowds" avoids the kind of mistakes that individuals can make, new research shows. In terms of evolutionary biology, animals strive to maximize their fitness. Still, actions that seem counterproductive and irrational occur not only in human societies, but also all over the animal kingdom. For instance, when honeybees and hummingbirds have two equally tempting choices of nectar, a third alternative inferior to both can sway them to prefer one of the initial two options over the other. The animals apparently compare the inferior choice against the originals and conclude that one of the originals is better, even though nothing about them has changed. Such irrationality can lead to deep insight, because "finding what makes the system fail can give a clue about how it works," explains Stephen Pratt, a behavioral ecologist at Arizona State University's School of Life Sciences in Tempe. Of special interest to Pratt is how groups of animals such as ant colonies make collective decisions. "We can even think of a colony as an analogue for a nervous systemby understanding how decisions emerge from interactions among ants in a colony, we may learn something about how decisions emerge from the interactions among neurons in a brain," he says. To see if collectives behave rationally, Pratt and his student Susan Edwards investigated a common acorn ant of eastern North America, Temnothorax curvispinosus, which is tinya colony of 50 to 200 such ants can make its home inside a single nutshell. When their nest is damaged beyond repair, the ants choose their new home en masse. Scouts look for potential nests, and if enough of them close in on the same area, they then carry nest mates over. The researchers made two artificial nests as potential homes. Nest A had a larger, less defensible entrance but a dark interior that suggested strong, thick walls, whereas nest B had a smaller entrance (more defensible) but a bright interior (weaker walls). As expected, when the researchers ran 26 ant colonies past these nests, the insects split roughly equally on the nests. Then they provided inferior "decoy" nests to spur irrational choices. For instance, if they presented a decoy that was similar to nest B yet had an even brighter interior, the ants might irrationally prefer nest B over nest A, if past results with humans and animals are any guide. Surprisingly, the decoys had no effect on the coloniesthey always made rational decisions. "All minds, both collective and individual, have limited capacitythey have to use shortcuts and rules of thumb to solve difficult decision problems, and those shortcuts are expected to sometimes cause mistakes," Pratt says. "The ant colonies, however, were unfazed by a challenge that often elicits such mistakes in other animals." So what makes these colonies so rational? Surprisingly, the very ignorance of the lone ants might be key. Instead of making comparisons between choices that can sway humans toward irrational decisions, individual ants typically know of just one option, which prevents them from making potentially misleading comparisons. Although the researchers expected the ants to behave irrationally, "we accidentally got a different insight about a possible advantage of collective cognition," says Pratt, whose findings appear today online in the Proceedings of the Royal Society B: Biological Sciences. "We thought our brains and those of most animals could not always decide rationally because it was impossible to do so," notes behavioral ecologist Anna Dornhaus of the University of Arizona in Tucson, who did not participate in this study. "The ants show us that…there is a way to construct a decision-making system" that doesn't make irrational choices. The question then, she observes, is why our brains have evolved to act irrationally on occasion. http://www.scientifi...decision-making Now there is a new study about the behavior of ants. Knowledgeable individuals lead collective decisions in ants Self-organisation underlies many collective processes in large animal groups, where coordinated patterns and activities emerge at the group level from local interactions among its members. Although the importance of key individuals acting as effective leaders has recently been recognised in certain collective processes, it is widely believed that self-organised decisions are evenly shared among all or a subset of individuals acting as decision-makers, unless there are significant conflicts of interests among group members. Here, we show that certain individuals are disproportionately influential in self-organised decisions in a system where all individuals share the same interests: nest site selection by the ant Temnothorax albipennis. Workers that visited a good available nest site prior to emigration (the familiar nest) memorised its location, and later used this memory to navigate efficiently and find that nest faster than through random exploration. Additionally, these workers relied on their private information to expedite individual decisions about the familiar nest. This conferred a bias in favour of familiar nests over novel nests during emigrations. Informed workers were shown to have a significantly greater share in both recruitment and transport to the familiar nest than naïve workers. This suggests that they were the main determinants of the collective preference for familiar nests, and thus contributed greatly to enhance collective performance. Overall, these results indicate that self-organised decisions are not always evenly shared among decision-makers, even in systems where there are no conflicts of interest. Animal groups may instead benefit from well-informed, knowledgeable individuals acting as leaders in decisions. http://jeb.biologist...cf-753fd3a881a5

Every day we make thousands of tiny predictions -- when the bus will arrive, who is knocking on the door, whether the dropped glass will break. Now, in one of the first studies of its kind, researchers at Washington University in St. Louis are beginning to unravel the process by which the brain makes these everyday prognostications. While this might sound like a boon to day traders, coaches and gypsy fortune tellers, people with early stages of neurological diseases such as schizophrenia, Alzheimer's and Parkinson's diseases could someday benefit from this research. In these maladies, sufferers have difficulty segmenting events in their environment from the normal stream of consciousness that constantly surrounds them. The researchers focused on the mid-brain dopamine system (MDS), an evolutionarily ancient system that provides signals to the rest of the brain when unexpected events occur. Using functional MRI (fMRI), they found that this system encodes prediction error when viewers are forced to choose what will happen next in a video of an everyday event. Predicting the near future is vital in guiding behavior and is a key component of theories of perception, language processing and learning, says Jeffrey M. Zacks, PhD, WUSTL associate professor of psychology in Arts & Sciences and lead author of a paper on the study in a forthcoming issue of the Journal of Cognitive Neuroscience. "It's valuable to be able to run away when the lion lunges at you, but it's super-valuable to be able to hop out of the way before the lion jumps," Zacks says. "It's a big adaptive advantage to look just a little bit over the horizon." Zacks and his colleagues are building a theory of how predictive perception works. At the core of the theory is the belief that a good part of predicting the future is the maintenance of a mental model of what is happening now. Now and then, this model needs updating, especially when the environment changes unpredictably. "When we watch everyday activity unfold around us, we make predictions about what will happen a few seconds out," Zacks says. "Most of the time, our predictions are right. "Successfull predictions are associated with the subjective experience of a smooth stream of consciousness. But a few times a minute, our predictions come out wrong and then we perceive a break in the stream of consciousness, accompanied by an uptick in activity of primitive parts of the brain involved with the MDS that regulate attention and adaptation to unpredicted changes." Zacks tested healthy young volunteers who were shown movies of everyday events such as washing a car, building a LEGO model or washing clothes. The movie would be watched for a while, and then it was stopped. Participants then were asked to predict what would happen five seconds later when the movie was re-started by selecting a picture that showed what would happen, and avoiding similar pictures that did not correspond to what would happen. Half of the time, the movie was stopped just before an event boundary, when a new event was just about to start. The other half of the time, the movie was stopped in the middle of an event. The researchers found that participants were more than 90 percent correct in predicting activity within the event, but less than 80 percent correct in predicting across the event boundary. They were also less confident in their predictions. "This is the point where they are trying hardest to predict the future," Zacks says. "It's harder across the event boundary, and they know that they are having trouble. When the film is stopped, the participants are heading into the time when prediction error is starting to surge. That is, they are noting that a possible error is starting to happen. And that shakes their confidence. They're thinking, 'Do I really know what's going to happen next?' " Zacks and his group were keenly interested in what the participants' brains were doing as they tried to predict into a new event. In the functional MRI experiment, Zacks and his colleagues saw significant activity in several midbrain regions, among them the substantia nigra -- "ground zero for the dopamine signaling system" -- and in a set of nuclei called the striatum. The substantia nigra, Zacks says, is the part of the brain hit hardest by Parkinson's disease, and is important for controlling movement and making adaptive decisions. Brain activity in this experiment was revealed by fMRI at two critical points: when subjects tried to make their choice, and immediately after feedback on the correctness or incorrectness of their answers. Mid-brain responses "really light up at hard times, like crossing the event boundary and when the subjects were told that they had made the wrong choice," Zacks says. Zacks says the experiments provide a "crisp test" of his laboratory's prediction theory. They also offer hope of targeting these prediction-based updating mechanisms to better diagnose early stage neurological diseases and provide tools to help patients. http://www.scienceda...10817175925.htm

New research by scientists in the Department of Biology at the University of York shows that species have responded to climate change up to three times faster than previously appreciated. These results are published in the latest issue of the leading scientific journal Science. Faster distribution changes. Species have moved towards the poles (further north in the northern hemisphere, to locations where conditions are cooler) at three times the rate previously accepted in the scientific literature, and they have moved to cooler, higher altitudes at twice the rate previously realised. Analysing data for over 2000 responses by animal and plant species, the research team estimated that, on average, species have moved to higher elevations at 12.2 metres per decade and, more dramatically, to higher latitudes at 17.6 kilometres per decade. Project leader Chris Thomas, Professor of Conservation Biology at York, said: "These changes are equivalent to animals and plants shifting away from the Equator at around 20 cm per hour, for every hour of the day, for every day of the year. This has been going on for the last 40 years and is set to continue for at least the rest of this century. " The link to climate change. This study for the first time showed that species have moved furthest in regions where the climate has warmed the most, unambiguously linking the changes in where species survive to climate warming over the last 40 years. First author Dr I-Ching Chen, previously a PhD student at York and now a researcher at the Academia Sinica in Taiwan, said: "This research shows that it is global warming that is causing species to move towards the poles and to higher elevations. We have for the first time shown that the amount by which the distributions of species have changed is correlated with the amount the climate has changed in that region." Co-author Dr Ralf Ohlemüller, from Durham University, said: "We were able to calculate how far species might have been expected to move so that the temperatures they experience today are the same as the ones they used to experience, before global warming kicked in. Remarkably, species have on average moved towards the poles as rapidly as expected." A diversity of changes. These conclusions hold for the average responses of species, but individual species showed much greater variation. Some species have moved much more slowly than expected, others have not moved, and some have even retreated where they are expected to expand. In contrast, other species have raced ahead, perhaps because they are sensitive to a particular component of climate change (rather than to average warming), or because other changes to the environment have also been driving their responses. Co-author Dr David Roy, from the Centre for Ecology & Hydrology, illustrates this variation among species: "In Britain, the high brown fritillary butterfly might have been expected to expand northwards into Scotland if climate warming was the only thing affecting it, but it has in fact declined because its habitats have been lost. Meanwhile, the comma butterfly has moved 220 kilometres northwards from central England to Edinburgh, in only two decades." Similar variation has taken place in other animal groups. Cetti's warbler, a small brown bird with a loud voice, moved northwards in Britain by 150 kilometres during the same period when the Cirl bunting retreated southward by 120 kilometres, the latter experiencing a major decline associated with the intensification of agriculture. How they did the research. The researchers brought together all of the known studies of how species have changed their distributions, and analysed them together in a "meta-analysis." The changes that were studied include species retreating where conditions are getting too hot (at low altitudes and latitudes), species expanding where conditions are no longer too cold (at high altitude and latitudes), and species staying where they are but with numbers declining in hotter parts and increasing in cooler parts of the range. They considered studies of latitudinal and elevational range shifts from throughout the world, but most of the available data were from Europe and North America. Birds, mammals, reptiles, insects, spiders, other invertebrates, and plants featured in the evidence. For example, I-Ching Chen and her colleagues discovered that moths had on average moved 67 metres uphill on Mount Kinabalu in Borneo. Co-author Jane Hill, Professor of Ecology at York, said: "We have taken the published literature and analysed it to detect what the overall pattern of change is, something that is not possible from an individual study. It's a summary of the state of world knowledge about how the ranges of species are responding to climate change. Our analysis shows that rates of response to climate change are two or three times faster than previously realised." Implications. The current research does not explicitly consider the risks posed to species from climate change, but previous studies suggest that climate change represents a serious extinction risk to at least 10 per cent of the world's species. Professor Thomas says: "Realisation of how fast species are moving because of climate change indicates that many species may indeed be heading rapidly towards extinction, where climatic conditions are deteriorating. On the other hand, other species are moving to new areas where the climate has become suitable; so there will be some winners as well as many losers." http://www.sciencedaily.com/releases/2011/08/110818142727.htm

I guess that viewing a computer causes some different problem for your health. It might not make your weight as bad as viewing a TV, but might hurt your musculoskeletal system and eyes more than latter.

The book writer may not be perfect for every detail. I think that your understanding is correct, which is enough.

Watching TV for an average of six hours a day could shorten the viewer's life expectancy by almost five years, indicates research published online in the British Journal of Sports Medicine. The impact rivals that of other well known behavioural risk factors, such as smoking and lack of exercise, the study suggests. Sedentary behaviour -- as distinct from too little exercise -- is associated with a higher risk of death, particularly from heart attack or stroke. Watching TV accounts for a substantial amount of sedentary activity, but its impact on life expectancy has not been assessed, say the authors. They used previously published data on the relationship between TV viewing time and death from analyses of the Australian Diabetes, Obesity and Lifestyle Study (AusDiab), as well as Australian national population and mortality figures for 2008, to construct a lifetime risk framework. AusDiab is a national survey of a representative sample of the population, starting in 1999-2000, and involving more than 11,000 adults aged 25 or older. The authors then constructed a risk framework for the Australian population in 2008, based on the answers the survey participants had given, when quizzed about the total amount of time they had spent in the previous week watching TV or videos. In 2008 the authors estimated that Australian adults aged 25 and older watched 9.8 billion hours of TV, which led them to calculate that every single hour of TV watched after the age of 25 shortened the viewer's life expectancy by just under 22 minutes. Based on these figures, and expected deaths from all causes, the authors calculated that an individual who spends a lifetime average of six hours a day watching TV can expect to live just under five fewer years than someone who does not watch TV. These figures compare with the impact of other well known lifestyle factors on the risk of death from cardiovascular disease after the age of 50, including physical activity and obesity. For example, other research has shown that lifelong smoking is associated with the shortening of life expectancy by more than 4 years after the age of 50, with the average loss of life from one cigarette calculated to be 11 minutes -- equivalent to half an hour of TV watching, according to the authors' risk framework. Their findings "suggest that substantial loss of life may be associated with prolonged TV viewing," say the authors. And they add: "While we used Australian data, the effects in other industrialised and developing countries are likely to be comparable, given the typically large amounts of time spent watching TV and similarities in disease patterns." They conclude: "If these [figures] are confirmed and shown to reflect a causal association, TV viewing is a public health problem comparable in size to established behavioural risk factors." http://www.scienceda...10815191414.htm Question: Does viewing to a computer monitor have the similar problem?

I am glad to take your comment.

Let me make this topic more interesting. Chimpanzees Are Spontaneously Generous After All Researchers at the Yerkes National Primate Research Center have shown chimpanzees have a significant bias for prosocial behavior. This, the study authors report, is in contrast to previous studies that positioned chimpanzees as reluctant altruists and led to the widely held belief that human altruism evolved in the last six million years only after humans split from apes. The current study findings are available in the online edition of Proceedings of the National Academy of Sciences. According to Yerkes researchers Victoria Horner, PhD, Frans de Waal, PhD, and their colleagues, chimpanzees may not have shown prosocial behaviors in other studies because of design issues, such as the complexity of the apparatus used to deliver rewards and the distance between the animals. "I have always been skeptical of the previous negative findings and their over-interpretation," says Dr. de Waal. "This study confirms the prosocial nature of chimpanzees with a different test, better adapted to the species," he continues. In the current study, Dr. Horner and colleagues greatly simplified the test, which focused on offering seven adult female chimpanzees a choice between two similar actions: one that rewards both the "actor," the term used in the paper for the lead study participant, and a partner, and another that rewards only the actor/chooser herself. Examples of the critically important simplified design aspects include allowing the study partners to sit close together and ensuring conspicuous food consumption, which the researchers achieved by wrapping pieces of banana in paper that made a loud noise upon removal. In each trial, the chooser, which was always tested with her partner in sight, selected between differently colored tokens from a bin. One colored token could be exchanged with an experimenter for treats for both members of the pair (prosocial); the other colored token would result in a treat only for the chooser (selfish). All seven chimpanzees showed an overwhelming preference for the prosocial choice. The study also showed the choosers behaved altruistically especially towards partners who either patiently waited or gently reminded them that they were there by drawing attention to themselves. The chimpanzees making the choices were less likely to reward partners who made a fuss, begged persistently or spat water at them, thus showing their altruism was spontaneous and not subject to intimidation. "We were excited to find female after female chose the option that gave both her and her partner food," says Dr. Horner. "It was also interesting to me that being overly persistent did not go down well with the choosers. It was far more productive for partners to be calm and remind the choosers they were there from time to time," she continues. The authors say this study puts to rest a longstanding puzzle surrounding chimpanzee altruism. It is well-known these apes help each other in the wild and show various forms of empathy, such as reassurance of distressed parties. The negative findings of previous studies did not fit this image. These results, however, confirm chimpanzee altruism in a well-controlled experiment, suggesting human altruism is less of an anomaly than previously thought. The study authors next plan to determine whether the altruistic tendency of the chimpanzees towards their partners is related to social interactions within the group, such as reciprocal exchanges of food or social support. For eight decades, the Yerkes National Primate Research Center, Emory University, has been dedicated to conducting essential basic science and translational research to advance scientific understanding and to improve the health and well-being of humans and nonhuman primates. Today, the center, as one of only eight National Institutes of Health-funded national primate research centers, provides leadership, training and resources to foster scientific creativity, collaboration and discoveries. Yerkes-based research is grounded in scientific integrity, expert knowledge, respect for colleagues, an open exchange of ideas and compassionate quality animal care. Within the fields of microbiology and immunology, neurologic diseases, neuropharmacology, behavioral, cognitive and developmental neuroscience, and psychiatric disorders, the center's research programs are seeking ways to: develop vaccines for infectious and noninfectious diseases; treat drug addiction; interpret brain activity through imaging; increase understanding of progressive illnesses such as Alzheimer's and Parkinson's diseases; unlock the secrets of memory; determine how the interaction between genetics and society shape who we are; and advance knowledge about the evolutionary links between biology and behavior. http://www.scienceda...10808152220.htm

The farther that human populations live from the equator, the bigger their brains, according to a new study by Oxford University. But it turns out that this is not because they are smarter, but because they need bigger vision areas in the brain to cope with the low light levels experienced at high latitudes. Scientists have found that people living in countries with dull, grey, cloudy skies and long winters have evolved bigger eyes and brains so they can visually process what they see, reports the journal Biology Letters. The researchers measured the eye socket and brain volumes of 55 skulls, dating from the 1800s, from museum collections. The skulls represented 12 different populations from across the globe. The volume of the eye sockets and brain cavities were then plotted against the latitude of the central point of each individual's country of origin. The researchers found that the size of both the brain and the eyes could be directly linked to the latitude of the country from which the individual came. Lead author Eiluned Pearce, from the Institute of Cognitive and Evolutionary Anthropology in the School of Anthropology, said: 'As you move away from the equator, there's less and less light available, so humans have had to evolve bigger and bigger eyes. Their brains also need to be bigger to deal with the extra visual input. Having bigger brains doesn't mean that higher latitude humans are smarter, it just means they need bigger brains to be able to see well where they live.' Co-author Professor Robin Dunbar, Director of the Institute of Cognitive and Evolutionary, said: 'Humans have only lived at high latitudes in Europe and Asia for a few tens of thousands of years, yet they seem to have adapted their visual systems surprisingly rapidly to the cloudy skies, dull weather and long winters we experience at these latitudes.' That the explanation is the need to compensate for low light levels at high latitudes is indicated by the fact that actual visual sharpness measured under natural daylight conditions is constant across latitudes, suggesting that the visual processing system has adapted to ambient light conditions as human populations have moved across the globe. The study takes into account a number of potentially confounding effects, including the effect of phylogeny (the evolutionary links between different lineages of modern humans), the fact that humans living in the higher latitudes are physically bigger overall, and the possibility that eye socket volume was linked to cold weather (and the need to have more fat around the eyeball by way of insulation). The skulls used in the study were from the indigenous populations of England, Australia, Canary Islands, China, France, India, Kenya, Micronesia, Scandinavia, Somalia, Uganda and the United States. From measuring the brain cavity, the research suggests that the biggest brains belonged to populations who lived in Scandinavia with the smallest being Micronesians. This study adds weight to other research that has looked at the links between eye size and light levels. Other studies have already shown that birds with relatively bigger eyes are the first to sing at dawn in low light. The eyeball size across all primates has been found to be associated with when they choose to eat and forage -- with species with the largest eyes being those that are active at night. http://www.scienceda...10804214410.htm

It sounds all of us believe that the generosity is caused by selfish of the genes. Does anyone think something different?

Thanks for the reminding. The link has been repaired.

Gardeners know that some trees require regular pruning: some of their branches have to be cut so that others can grow stronger. The same is true of the developing brain: cells called microglia prune the connections between neurons, shaping how the brain is wired, scientists at the European Molecular Biology Laboratory (EMBL) in Monterotondo, Italy, discovered. Published online in Science, the findings could one day help understand neurodevelopmental disorders like autism. "We're very excited, because our data shows microglia are critical to get the connectivity right in the brain," says Cornelius Gross, who led the work: "they 'eat up' synapses to make space for the most effective contacts between neurons to grow strong." Microglia are related to the white blood cells that engulf pathogens and cellular debris, and scientists knew already that microglia perform that same clean-up task when the brain is injured, 'swallowing up' dead and dying neurons. Looking at the developing mouse brain under the microscope, Gross and colleagues found proteins from synapses -- the connections between neurons -- inside microglia, indicating that microglia are able to engulf synapses too. To probe further, the scientists introduced a mutation that reduced the number of microglia in the developing mouse brain. "What we saw was similar to what others have seen in at least some cases of autism in humans: many more connections between neurons," Gross says. "So we should be aware that changes in how microglia work might be a major factor in neurodevelopmental disorders that have altered brain wiring." The microglia-limiting mutation the EMBL scientists used has only temporary effects, so eventually the number of microglia increases and the mouse brain establishes the right connections. However, this happens later in development than it normally would, and Gross and colleagues would now like to find out if that delay has long-term consequences. Does it affect the behaviour of the mice behaviour, for example? At the same time, Gross and colleagues plan to investigate what microglia do in the healthy adult brain, where their role is essentially unknown. This work was carried out in collaboration with the groups of Davide Ragozzino at the University of Rome and Maurizio Giustetto and Patrizia Panzanelli at the University of Turin. http://www.sciencedaily.com/releases/2011/07/110721142410.htm

Imagine you're dining at a restaurant in a city you're visiting for the first -- and, most likely the last -- time. Chances are slim to none that you'll ever see your server again, so if you wanted to shave a few dollars off your tab by not leaving a tip, you could do so. And yet, if you're like most people, you will leave the tip anyway, and not give it another thought. These commonplace acts of generosity -- where no future return is likely -- have long posed a scientific puzzle to evolutionary biologists and economists. In acting generously, the donor incurs a cost to benefit someone else. But choosing to incur a cost with no prospect of a compensating benefit is seen as maladaptive by biologists and irrational by economists. If traditional theories in these fields are true, such behaviors should have been weeded out long ago by evolution or by self-interest. According to these theories, human nature is fundamentally self-serving, with any "excess" generosity the result of social pressure or cultural conformity. Recently, however, a team of scientists at UC Santa Barbara conducted a series of computer simulations designed to test whether it was really true that evolution would select against generosity in situations where there is no future payoff. Their work surprisingly shows that generosity -- acting to help others in the absence of foreseeable gains -- emerges naturally from the evolution of cooperation. This means that human generosity is likely to rest on more than social pressure, and is instead built in to human nature. Their findings appear in the current issue of the Proceedings of the National Academy of Sciences. "When past researchers carefully measured people's choices, they found that people all over the world were more generous than the reigning theories of economics and biology predicted they should be," said Max M. Krasnow, a postdoctoral scholar at UCSB's Center for Evolutionary Psychology, and one of the paper's lead authors. "Even when people believe the interaction to be one-time only, they are often generous to the person they are interacting with." "Our simulations explain that the reason people are more generous than economic and biological theory would predict is due to the inherent uncertainty of social life," added Andrew Delton, also a postdoctoral scholar at the Center for Evolutionary Psychology and the paper's other lead author. "Specifically, you can never know for certain whether an interaction you are having right now will be one-time only -- like interacting with a server in a distant city -- or continue on indefinitely -- like interacting with a server at your favorite hometown diner." Krasnow and Delton co-authored the paper with Leda Cosmides, professor of psychology and co-director of the Center for Evolutionary Psychology; and John Tooby, professor of anthropology and also co-director of the Center for Evolutionary Psychology. "There are two errors a cooperating animal can make, and one is more costly than the other," noted Cosmides. "Believing that you will never meet this individual again, you might choose to benefit yourself at his expense -- only to find out later that the relationship could have been open-ended. If you make this error, you lose out on all the benefits you might have had from a long-term, perhaps life-long, cooperative relationship. This is an extraordinarily costly error to make. The other error is to mistakenly assume that you will have additional interactions with the other individual and therefore cooperate with him, only to find out later that it wasn't necessary. Although you were 'unnecessarily' nice in that one interaction, the cost of this error is relatively small. Without knowing why, the mind is skewed to be generous to make sure we find and cement all those valuable, long-term relationships." The simulations, which are mathematical tools for studying how natural selection would have shaped our ancestors' decision making, show that, over a wide range of conditions, natural selection favors treating others as if the relationship will continue -- even when it is rational to believe the interaction is one-time only. "Although it's impossible to know the true state of the world with complete certainty, our simulated people were designed to use the 'gold-standard' for rational reasoning -- a process called Bayesian updating -- to make the best possible guesses about whether their interactions will continue or not," Krasnow noted. Delton continued: "Nonetheless, even though their beliefs were as accurate as possible, our simulated people evolved to the point where they essentially ignored their beliefs and cooperated with others regardless. This happens even when almost 90 percent of the interactions in their social world are actually one-time rather than indefinitely continued." According to Tooby, economic models of rationality and evolutionary models of fitness maximization both predict that humans should be designed to be selfish in one-time only situations. Yet, experimental work -- and everyday experience -- shows that humans are often surprisingly generous. "So one of the outstanding problems in the behavioral sciences was why natural selection had not weeded out this pleasing but apparently self-handicapping behavioral tendency," Tooby said. "The paper shows how this feature of human behavior emerges logically out of the dynamics of cooperation, once an overlooked aspect of the problem -- the inherent uncertainty of social life -- is taken into account. People who help only when they can see a gain do worse than those who are motivated to be generous without always looking ahead to see what they might get in return." http://www.sciencedaily.com/releases/2011/07/110725162523.htm

Show a man a picture of an attractive woman, and he might play riskier blackjack. With a real-life pretty woman watching, he might cross traffic against a red light. Such exhibitions of agility and bravado are the behavioral equivalent in humans of physical attributes such as antlers and horns in animals. “Mate with me,” they signal to women. “I can brave danger to defend you and the children.” So says Lei Chang, a psychologist at the Chinese University of Hong Kong. With colleagues there and at China’s Hebei University, Chang wondered wheth­er military weaponry and parapherna­lia hold the same seductive value as antlers, horns and risky behavior, allowing warriors to best nonwarriors in the competition for mates. The researchers also speculated about war itself. When raping and pillaging, armies resemble chimps on intergroup sex raids. Might warfare actually be driven by the opportunity it offers males to impregnate females, willing and not willing? To begin to address such questions, Chang showed men pictures of women and tested for statistically significant effects of those pictures on men’s attitudes about war and on their cognitive processes related to war. As he and his colleagues describe in the online March 23 Personality and Social Psychology Bulletin, they asked the men to rate their agreement with war-supporting statements. Men’s responses demonstrated a positive, significant statistical correlation between seeing photographs of attractive faces and endorsing war-supporting statements. This correlation was not demonstrated for photographs of unattractive women’s faces, and the researchers found no statistically significant effect on women of pictures of either attractive or unattractive men in any measure related to war. Chang and his colleagues suggest that any warring-mating relation in men is probably an evolutionary holdover from pre–Homo sapiens days, which explains why raping and pillaging are, unfortunately, alive and well. http://www.scientificamerican.com/article.cfm?id=beauty-and-the-beasts

Before I say anything I have to be clear that I am not expert about PET scan. I would expect some difference of the scanned images between your headache time and no headache time. The reason may or may not be due to the headache itself, instead, may be due to the negative emotion induced by the headache. PET scan can show some of the affection of emotions. Again, you should ask your doctor for this question.

There are very few professions like what Einstein was doing and very few brains like what Einstein had. In reality, the most of the jobs require a lot of memories. For example, if you are a medical doctor you definitely need a great deal of memories to treat patients correctly.

To establish an explict memory, it usually needs help by some kind of motivation. This reseach supports my thought. Such is similar thing happened again and again. For example, the electronic calculators extended users' math power but reduced their math capability in their brains.

I am not expert at all because it is too far from my field. Here is just some idea to share. The air compression is a possible phenomena in a gust of wind. Human body is not very sensitive to such in short period. When you are jogging in a gym (no wind pretty much), the air pressure on your front is higher than its on your back. But you don't noticed that.

Two photos, thirty years apart, move the Web http://news.yahoo.com/blogs/upshot/two-photos-thirty-years-apart-move-192313669.html

It's clear that has been called "social loafing" in psychology. http://en.wikipedia.org/wiki/Social_loafing

Researchers at Columbia Engineering School have built optical nanostructures that enable them to engineer the index of refraction and fully control light dispersion. They have shown that it is possible for light (electromagnetic waves) to propagate from point A to point B without accumulating any phase, spreading through the artificial medium as if the medium is completely missing in space. This is the first time simultaneous phase and zero-index observations have been made on the chip-scale and at the infrared wavelength. The study, to be published in Nature Photonics, was led by Chee Wei Wong, associate professor of mechanical engineering, and Serdar Kocaman, electrical engineering PhD candidate, both at Columbia Engineering, in collaboration with scientists at the University College of London, Brookhaven National Laboratory, and the Institute of Microelectronics of Singapore. "We're very excited about this. We've engineered and observed a metamaterial with zero refractive index," said Kocaman. "What we've seen is that the light disperses through the material as if the entire space is missing. The oscillatory phase of the electromagnetic wave doesn't even advance such as in a vacuum -- this is what we term a zero-phase delay." This exact control of optical phase is based on a unique combination of negative and positive refractive indices. All natural known materials have a positive refractive index. By sculpturing these artificial subwavelength nanostructures, the researchers were able to control the light dispersion so that a negative refractive index appeared in the medium. They then cascaded the negative index medium with a positive refractive index medium so that the complete nanostructure behaved as one with an index of refraction of zero. "Phase control of photons is really important," said Wong. "This is a big step forward in figuring out how to carry information on photonic chips without losing control of the phase of the light." "We can now control the flow of light, the fastest thing known to us," he continued. "This can enable self-focusing light beams, highly directive antennas, and even potentially an approach to cloak or hide objects, at least in the small-scale or a narrow band of frequencies currently." This research was supported by grants from the National Science Foundation and the Defense Advanced Research Projects Agency. http://www.sciencedaily.com/releases/2011/07/110710132825.htm

"Benefits" of having WWI and WWII?! For the sake of the people lost everything in these wars, please DO NOT use such word.

How easy is it to falsify memory? New research at the Weizmann Institute shows that a bit of social pressure may be all that is needed. The study, which appears in the journal Science, reveals a unique pattern of brain activity when false memories are formed -- one that hints at a surprising connection between our social selves and memory. The experiment, conducted by Prof. Yadin Dudai and research student Micah Edelson of the Institute's Neurobiology Department with Prof. Raymond Dolan and Dr. Tali Sharot of University College London, took place in four stages. In the first, volunteers watched a documentary film in small groups. Three days later, they returned to the lab individually to take a memory test, answering questions about the film. They were also asked how confident they were in their answers. They were later invited back to the lab to retake the test while being scanned in a functional MRI (fMRI) that revealed their brain activity. This time, the subjects were also given a "lifeline": the supposed answers of the others in their film viewing group (along with social-media-style photos). Planted among these were false answers to questions the volunteers had previously answered correctly and confidently. The participants conformed to the group on these "planted" responses, giving incorrect answers nearly 70% of the time. But were they simply conforming to perceived social demands, or had their memory of the film actually undergone a change? To find out, the researchers invited the subjects back to the lab to take the memory test once again, telling them that the answers they had previously been fed were not those of their fellow film watchers, but random computer generations. Some of the responses reverted back to the original, correct ones, but close to half remained erroneous, implying that the subjects were relying on false memories implanted in the earlier session. An analysis of the fMRI data showed differences in brain activity between the persistent false memories and the temporary errors of social compliance. The most outstanding feature of the false memories was a strong co-activation and connectivity between two brain areas: the hippocampus and the amygdala. The hippocampus is known to play a role in long-term memory formation, while the amygdala, sometimes known as the emotion center of the brain, plays a role in social interaction. The scientists think that the amygdala may act as a gateway connecting the social and memory processing parts of our brain; its "stamp" may be needed for some types of memories, giving them approval to be uploaded to the memory banks. Thus social reinforcement could act on the amygdala to persuade our brains to replace a strong memory with a false one. An accompanying video is available at: http://www.youtube.com/user/WeizmannInstitute#p/u/0/bKCCYhHUTPE Prof. Yadin Dudai's research is supported by the Norman and Helen Asher Center for Human Brain Imaging, which he heads; the Nella and Leon Benoziyo Center for Neurological Diseases; the Carl and Micaela Einhorn-Dominic Institute of Brain Research, which he heads; the Marc Besen and the Pratt Foundation, Australia; Lisa Mierins Smith, Canada; Abe and Kathryn Selsky Memorial Research Project; and Miel de Botton, UK. Prof. Dudai is the incumbent of the Sara and Michael Sela Professorial Chair of Neurobiology. http://www.scienceforums.net/index.php?app=forums&module=post&section=post&do=new_post&f=23

I like the discussion because I have never been there yet.

Under certain conditions, private and commercial propeller planes and jet aircraft may induce odd-shaped holes or canals into clouds as they fly through them. These holes and canals have long fascinated the public and now new research shows they may affect precipitation in and around airports with frequent cloud cover in the wintertime. Here is how: Planes may produce ice particles by freezing cloud droplets that cool as they flow around the tips of propellers, over wings or over jet aircraft, and thereby unintentionally seed clouds. These seeding ice particles attract more moisture, becoming heavier, and then "snow out" or fall out of the cloud as snow along the path of a plane, thereby creating a hole in a cloud. The effects of this inadvertent cloud seeding are similar to the effects of the intentional seeding of clouds: that is, both processes may increase the amount of precipitation falling from clouds. The study, which was partially funded by the National Center for Atmospheric Research (NCAR) in Boulder, Colo., appears in the July 1, 2011 issue of the journal Science. NCAR is partially funded by the National Science Foundation. "It is unlikely that the hole-punching ability of planes affects global climate," says Andrew Heymsfield of NCAR, the study's lead author. But because the hole-punching ability of planes is particularly high when they fly through low subfreezing clouds, major airports that are covered in low clouds during winter are particularly vulnerable to precipitation associated with this inadvertent seeding. This vulnerability means it may be necessary to de-ice planes more frequently, Heymsfield says. Also, because weather station records that climate modelers incorporate into climate predictions are housed at airports in the Arctic and Antarctic, climate predictions for these areas may be influenced by local weather conditions caused by inadvertent seeding near those airports. Heymsfield says that his team's latest research built on a paper published by the team last year on a similar topic in the Bulletin of the American Meteorological Society by: 1) evaluating the exact types of aircraft that produce airplane induced holes and canals; 2) measuring the spread and persistence of the holes; 3) hypothesizing the mechanisms for the spread of holes; 4) numerically modeling the holes; 5) defining the processes for their spread and persistence; and 6) examining how often hole punched clouds and associate effects may occur near several major airports. http://www.scienceda...10701121623.htm