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 队友们，明天周二的科技文又来了。
速度不难，文章长度也适中。越障的长度。。。就。。。大家Hold住，文章思路挺不错的，内容多了点。这个时候，为了把握中心结构和思路，就要适当地跳读抓重点了。
加油！
Part I Speed
Article I (Check the title later)
A handy tip: Keeping a straight face is not enough
Apr 20th 2013 |From the print edition
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【Time1】
A POKER face. It is the expressionless gaze that gives nothing away. To win at poker, the face must be mastered, and master it is what the best players try their best to do. But a study just published in Psychological Science by Michael Slepian of Stanford University and his colleagues suggests that even people with the best poker faces give the game away. They do so, however, not with their heads but with their hands.
Mr Slepian made his discovery when he showed 78 undergraduate volunteers video clips of players placing bets at the 2009 World Series of Poker. (Bets in poker are placed by pushing chips into the middle of the table.) The clips were 1.6 seconds long, on average, and featured different parts of the players’ anatomies. Some showed everything visible from the table up: chest, arms and head. Some showed just the face. And some showed only the arms and hands. Each volunteer watched only one of the three types of video, but was shown several examples.
After each viewing, volunteers were asked to rate the quality of the player’s hand on a seven-point scale. Then, when they had finished watching all the clips, they were asked to rate their own experience with poker on a similar scale.
Mr Slepian found that students were poor at judging the quality of a player’s hand when shown just that player’s face. Indeed, he noticed a negative correlation of 0.07. This is not huge (a perfect correlation is 1.0). But it meant there was a statistically significant tendency that the better a volunteer believed the hand to be, the worse it actually was. When a player’s whole posture was considered, this misapprehension went away: if a volunteer could see everything about a player from the table up there was no correlation between his judgments of a hand’s value and its actual value. When a volunteer could see only arms and hands, however, Mr Slepian found a positive correlation, of 0.07, between his guesses and reality.
【336 words】
【Time2】
To confirm his discovery, Mr Slepian re-ran the experiment with a different set of clips. The results were the same. Students, even those who were poker novices, could judge the quality of a professional poker player’s cards from the behaviour of his hands. The next question was, how?
Mr Slepian knew from previous studies by other people that anxiety has a tendency to disrupt smooth body movements, and he suspected this might be the explanation. To find out, he showed 40 new volunteers the clips he had used in the previous experiment. Rather than asking them to judge the quality of a player’s cards, however, he asked them to rate either that player’s confidence or how smoothly the player pushed his chips into the middle of the table.
He found that when students rated players as being confident or having hands that moved smoothly, the cards they held were likely to be good. There was a positive correlation of 0.15 when the students considered confidence and of 0.29 when they looked for smooth movement, so they were actually more capable of determining hand quality from these variables than when asked to estimate it directly. The moral of the story for players, then, is don’t look your opponent squarely in the eye if you want to know how good his cards are. The secret of his hand is in his hands.
【223 words】
Article II (Check the title later)
The Human Brainome Project
Obama announces ambitious plan to develop new tools for exploring neural circuitry
By Puneet Kollipara
Web edition: April 18, 2013
Print edition: May 4, 2013; Vol.183 #9 (p. 22)
【Time3】
Brain research has been on a lot of minds lately in the nation’s capital. After offering a brief shout-out to Alzheimer’s research in his February State of the Union address, President Barack Obama went a step further in April by announcing a decade-long effort to develop advanced tools for tracking human brain activity. The administration dubbed it the Brain Research through Advancing Innovative Neurotechnologies initiative, and proposed spending $100 million on the program in the 2014 fiscal year.
Scientists have discussed such an endeavor for years, and pushed hard for it in the past few months. Writing March 15 in Science, researchers say the project would develop technologies to probe brain activity on a far greater scale and with higher resolution than is now possible.
Current tools can monitor only small numbers of individual neurons at a time or capture blurry, bird’s-eye views of brain activity. The new tools would enable real-time mapping of how the thousands or millions of neurons in coordinated groups, known as circuits, work together. Brain functions — and, in many cases, dysfunctions — are thought to emerge from this still poorly described circuit level.
“There’s no way to build a map until you develop the tools,” says Rafael Yuste, a neuroscientist at Columbia University’s Kavli Institute for Brain Science and one of the project’s proponents.
Researchers call for developing three sets of tools to better understand brain circuits. One focus is on the creation of tools to measure the activities of all the individual neurons in a circuit. Another is on technologies to experimentally manipulate these neurons. The third tool set would store, analyze and make the data accessible to all researchers.
Scientists today can directly probe individual neurons to examine the main currency of neuronal communication, electrical signals known as action potentials. But the existing tools are generally invasive, making them tough to use in humans, or have crude resolution. New technologies, some already emerging, would be nanoscale, proponents of the effort write March 26 in ACS Nano, or they would measure voltage indirectly through an indicator. Other possible targets include chemical messengers known as neurotransmitters, which relay action potentials between neurons via synapses.
【359】
【Time4】
For instance, researchers already use laser microscopes to measure calcium ions, an indicator of voltage. One recent study used a special laser microscope that emits a “light sheet” to detect calcium ions and map the activity of 80 percent of a larval zebra fish’s roughly 100,000-neuron brain. Coauthor Misha Ahrens of the Howard Hughes Medical Institute in Ashburn, Va., likens the method to shining a thin sheet of light instead of a lamp in a foggy area; the thin layer would be scattered far less by the fog than the diffuse lamplight would.
The map, described March 18 in Nature Methods, shows activity once a second. It may be the first time vertebrate brain activity has ever been revealed in such detail. To go further and capture the brain’s workings at a rate of 1,000 times a second, as scientists would like, will require major changes in microscope technology, Ahrens says.
Another exciting prospect is the use of quantum dots, nanoscale semiconducting spheres that can be engineered to glow a different color or brightness depending on voltage or neurotransmitter levels.
Researchers even envision artificial cells that could serve as liaisons between measurement tools and neurons, says George Church, a Harvard University geneticist who helped plan the initiative and was a leading figure in the Human Genome Project.
【217】
【Time5】
Flipping switches
While imaging and measurement tools would enable researchers to link neuron activity or neurotransmitter levels with certain functions or dysfunctions of the brain, manipulating individual neurons could lead to even more powerful experiments. It also could lead to clinical applications.
In the burgeoning field of optogenetics, neurons are engineered to turn on or off in response to light. “We can selectively activate individual neurons. By doing that, you can really get at issues of causality,” says Clay Reid, a neurobiologist at the Allen Institute for Brain Science in Seattle.
Reporting April 3 in Nature, researchers at the National Institute on Drug Abuse in Baltimore and the University of California, San Francisco used optogenetics to produce or diminish compulsive cocaine use in rats by manipulating the activity of a specific group of neurons.
Researchers hope the findings lead to new therapies for drug addiction, but the road to clinical application is a difficult one and requires a sustained investment. “The evolution of optogenetics or similar techniques needs a lot of help, because the benefits are going to far, far outweigh the costs,” says coauthor Antonello Bonci of NIDA.
A huge advantage of optogenetics, he says, is that it can manipulate neurons almost in real time. But it can’t be used for long periods. In his lab, Bonci complements optogenetics with another promising technique that has lower time resolution but can be used for longer. It involves implanting neurons engineered to respond to certain compounds. Injecting those compounds can activate or silence the cells.
【254】
【The Rest】
Preparing for the data flood
Monitoring and manipulating individual cells is only part of the challenge; tracking a million neurons a thousand times a second will produce a lot of data. Software, databases and hardware will be needed to store and distribute that information, and to process and analyze it. Project proponents met at Caltech in January to discuss how to address the data needs — roughly a gigabyte a second for a million neurons simultaneously, or 30 million gigabytes a year.
Researchers could compress the data by a factor of 10 without sacrificing crucial details, according to a report from the meeting. Ultimately, the data problem shouldn’t be insurmountable, Yuste says. Another proposed big science project, the Large Synoptic Survey Telescope, would produce around 10 million gigabytes of astronomical data annually starting in the early 2020s — right when million-neuron tools could come online, he notes.
Technical obstacles aren’t the only worry Yuste and his colleagues have. The recurring state of fiscal crisis in Washington makes it difficult to get any big project off the ground. Uncertainty over funding has fueled skepticism among scientists, who wonder whether money would be taken from other research to fund a “Big Science” project that lacks a concrete final goal.
National Institutes of Health Director Francis Collins notes that his agency has formed a workgroup of neuroscientists and some nanoscientists — supportive and skeptical alike — to guide the project’s timetable and scientific goals. One of the cochairs is Cori Bargmann, a Rockefeller University neuroscientist who previously raised concerns that the project could take funding from other neuroscience work.
Gary Marcus, a neuroscientist at New York University, says he is concerned that the project focuses too much on tool development, but notes that the administration’s proposal may be flexible enough to fund projects in other areas of neuroscience.
He fears what will happen if the tools are developed but don’t yield all the promised insights. “We will surely learn something,” Marcus says. “Whether we learn everything we want to know is another question.”
【336】
Part II Obstacle
Article III (Check the tittle later)
A Different Kind of Smart
Animals’ cognitive shortcomings are as revealing as their genius
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By Susan Milius
Web edition: April 18, 2013
Print edition: May 4, 2013; Vol.183 #9 (p. 24)
【Time6】
Zola the crow is about to face a test that has baffled animals from canaries to dogs.
She’s a wild New Caledonian crow, and for the first time, she’s seeing a tidbit of meat dangling on a long string tied to a stick. She perches on the stick, bends down, grabs the string with her beak and pulls. But the string is too long. The meat still hangs out of reach.
In similar tests, dogs, pigeons and many other species routinely falter. Some nibble at the string or keep tugging and dropping the same segment. Some pull at a string that’s not connected to food just as readily as a string that is. Eventually many get the hang of reeling in the tidbit, but they seem to learn by trial and error.
Zola, however, does not fumble. On her first attempt, she anchors the first length of string by stepping on it and immediately bends down again for the next segment. With several more pulls and steps, Zola reels in the treat.
Watching the crow, says Russell Gray, one of the researchers behind the string-pulling experiment, “people say, ‘Wow, it had a flash of insight.’ ” At first glance it seems Zola mentally worked through the problem as a human might, devising a solution in an aha moment.
But Gray, of the University of Auckland in New Zealand, has had enough of such supposed animal geniuses. Asking whether the crow solves problems in the same way a human would isn’t a useful question, he says. He warns of a roller coaster that scientists and animal lovers alike can get stuck on: first getting excited and romanticizing a clever animal’s accomplishments, then crashing into disappointment when some killjoy comes up with a mundane explanation that’s not humanlike at all.
Gray is looking for a way to get off the roller coaster. In Zola’s case, he and his colleagues devised several different variations on the string-pulling test that would never trip up a human, and the crow’s smooth performances fell apart. Whatever Zola was doing to solve the puzzle, Gray says, it’s not full, humanlike insight.
That may disappoint some people, but not Gray. “Often we learn the most when we see what we can change that makes the apparently impressive performance collapse,” he says.
He and a handful of other researchers are studying not only what animals can do, but also what they can’t. Forget the animal Einsteins — give Gray the not-so-miraculous beasts that ace one version of a test but flunk another.
After all, seeing an animal succeed at a mental challenge reveals little about how it evolved that capacity. Evolution doesn’t proceed by astonishing leaps, but by baby steps. “I’m interested in halfway scenarios, intermediate scenarios,” Gray says. These modest capabilities, he argues, offer the richest inspiration for understanding the small steps that build up into the rich diversity of animals’ mental powers.
Clever creatures
That’s not to say that scientists haven’t been looking for signs that animals have humanlike thought processes. Recent decades have seen a flood of reports that animals share some degree of capabilities once assumed to be uniquely human. Recently hatched chicks manage simple addition and subtraction, correctly keeping track of which of two hidden groups of familiar objects is larger. Foraging rock ants look as if they’re among the very few animals to show true teaching behavior. Sheep have sophisticated powers of facial recognition and can remember 50 of their fellows for two years. Black bears can learn to sort images into categories, such as bears versus humans. Dolphins can use tools, carrying sponges that protect their sensitive snouts while foraging.
None other than Charles Darwin noted many examples of humanlike cleverness in animals, which he celebrated as support for evolution’s tenet of shared deep ancestry, says Sara Shettleworth of the University of Toronto.
The unintended result of Darwin’s remarks was such uncritical enthusiasm for anecdotes about clever animals, however, that a backlash struck as early as 1894. That year, British psychologist C. Lloyd Morgan published what’s called Morgan’s canon, the principle that suggestions of humanlike mental processes behind an animal’s behavior should be rejected if a simpler explanation will do.
Still, people seem to maintain certain expectations, especially when it comes to birds and mammals. “We somehow want to prove they are as ‘smart’ as people,” Shettleworth says. We want a bird that masters a vexing string to be employing human-style insight.
Aha moments
New Caledonian crows face the high end of these expectations, as possibly the second-best toolmakers on the planet.
Their tools are hooked sticks or strips made from spike-edged leaves, and they use them in the wild to winkle grubs out of crevices. Gray first saw the process on a cold morning in a mountain forest in New Caledonia, an island chain east of Australia. Over the course of days, he and crow researcher Gavin Hunt had gotten wild crows used to finding meat tidbits in holes in a log. Once the birds were checking the log reliably, the researchers placed a spiky tropical pandanus plant beside the log and hid behind a blind.
A crow arrived. It hopped onto the pandanus plant, grabbed the spiked edge of one of the long straplike leaves and began a series of ripping motions. Instead of just tearing away one long strip, the bird ripped and nipped in a sequence to create a slanting stair-step edge on a leaf segment with a narrow point and a wide base. The process took only seconds. Then the bird dipped the narrow end of its leaf strip into a hole in the log, fished up the meat with the leaf-edge spikes, swallowed its prize and flew off.
“That was my ‘oh wow’ moment,” Gray says. After the crow had vanished, he picked up the tool the bird had left behind. “I had a go, and I couldn’t do it,” he recalls. Fishing the meat out was tricky. It turned out that Gray was moving the leaf shard too forcefully instead of gently stroking the spines against the treat.
The crows’ deft physical manipulation was what inspired Gray and Auckland colleague Alex Taylor to test Zola and other wild crows to see if they employed the seemingly insightful string-pulling solutions that some ravens, kea parrots and other brainiac birds are known to employ. Three of four crows passed that test on the first try, so next the researchers set out to test the crows’ limits.
Gray and Taylor set up a platform instead of a perch, which limited what the crows could see while pulling the string. The birds could investigate the string and the dangling meat from the sides but had to hop onto the platform and pull the string up through a slot. The supposedly insightful toolmakers had a terrible time. Out of four birds that had never confronted a dangling tidbit, only one hauled in the treat, and that was on the fifth try. Another bird failed at 10 opportunities, pulling at the string 188 times but never stepping on it.
In another test, researchers laid the string on a table in S-curve loops. The birds could see the meat, but they wouldn’t see it moving closer until they’d pulled enough times to reach the last segment of string.
An animal with true insight, in theory, would recognize that continuing to pull the string would eventually pull in the meat. But in this setup, the birds “completely fail,” Gray says. Some gave the string a tug at first, but only one kept hauling. And that bird was just as happy to pull on a string not connected to meat as on one that was, Gray, Taylor and their colleagues reported in the Proceedings of the Royal Society B in a 2012 paper titled “An end to insight?”
After seeing all this, the researchers proposed that Zola and the other crows had solved the first test — the perch with the hanging string — not by insight in the human sense, but through an enhanced ability to pay attention. New Caledonian crows, which do have relatively large brains for their body size, may be able to notice and absorb in detail the consequences of what they’re doing. Reaching down to grab the dangling string isn’t a big change from normal poking and exploring. And when the meat rises a bit, the birds absorb the positive feedback and take another step-pull.
As mental prowess goes, Gray says, “that’s not a miracle, just a small tweak in cognition.”
【1420】
【Extensive reading】
Physics test
Researchers have done a similar kind of tweaking using experiments based on Aesop’s fables. In one of the old tales, a thirsty crow finds a jug partly full of water but can’t reach down far enough for a drink. So the bird plops stones into the jug until the water level rises.
Nathan Emery and Chris Bird of Queen Mary, University of London taught real-life rooks a version of this trick. The researchers gave birds a tube partly filled with water and a waxworm bobbing on the water’s surface. The rooks readily dropped stones into the water until they could grab the treat. (Orangutans in lab tests have solved the problem in their own way, taking mouthfuls of water from their drinking supply and spitting into the tube to raise the water level.)
To see if the behavior extended to a related group of birds, Nicola Clayton and her colleagues tested Eurasian jays. “The birds often walk around the tubes having a good look first,” says Clayton, who studies the evolution of animal cognition at the University of Cambridge in England. Soon two of five jays began to drop stones into the water to score a waxworm. Those two also learned a preference for dropping in pieces of rubber that sink instead of foam chunks that float uselessly on the surface. “This is especially striking because when we tested children, the children don’t pass this version of the task until quite late in development,” Clayton says. One 5-year-old grasped the value of sinking objects, but overall the successful children averaged more than 8 years of age.
Then researchers devised a counterintuitive set-up, offering three tubes partly filled with water. The treat floated in the middle one, but that tube was too narrow for a stone. The only way a jay or child could score the treat (kids got tokens to exchange for stickers instead of waxworms) was to drop stones into one of the outer tubes that had a hidden connection to the narrow middle tube. Jays just didn’t get it, but a substantial number of 8- to 10-year-olds did, although “most of them didn’t understand why the setup worked,” Clayton says. “They attributed it to magic.”
Neither the jays nor the kids managed the trickiest tasks the way an adult human would. But like Gray, Clayton is intrigued by the partial successes. In the last test, she speculates, children may be better able than jays to accept the counterintuitive quirk of the secretly connected tube. “Without a belief in magic,” she says, “jays fail to figure it out.”
Reading minds
Besides studying how birds solve physical problems, Clayton has tested the notion that a bird can imagine, in some sense, what’s going on in another animal’s head. People have this ability, called theory of mind, but proposing, as Clayton does, that the Western scrub-jay can infer what another bird is thinking is a striking conclusion.
Scrub-jays cache food, and possess prodigious powers for remembering where. They also steal from each others’ caches, with higher-ranking birds tending to steal from lower-ranked birds. Clayton has found that if a bird with a larcenous past knows it’s being watched as it stashes a tidbit, it’s likely to later shift the cache to an unobserved location. This suggests that the birds have something like a theory of mind, Clayton says, because they understand that the bird watching them may come steal their stores. Yet nonthieves aren’t as likely to recache the food. So jays that steal may project their own behavior onto other birds that are watching them.
Elske van der Vaart of the University of Amsterdam has been looking for a simpler explanation. Maybe the birds are not relying on something even close to a human’s theory of mind, she and her colleagues suggested in PLOS ONE in 2012. Maybe all the hiding and rehiding is just a side-effect of something as simple as stress. Being watched is stressful, the researchers say, as is failing to find a cache. In experiments with virtual birds in a computer simulation, flustered individuals that were being watched and following a simple rule (they cached as far away as possible from observers) hid and rehid their hoard much as real scrub-jays do.
But real birds don’t behave like simulated birds, Clayton and Cambridge colleague James Thom reported in January in PLOS ONE. Given a chance to hide peanuts in ice cube trays, birds cached about the same number of treats in both more and less stressful conditions.
“Sometimes the simplest explanation is not the best,” Clayton says.
So the debate about theory of mind continues. Van der Vaart says the supposedly serene ice cube–tray situations might have held hidden stresses that confounded the results. And other predictions from computer simulations still need testing. “I certainly do think it’s possible that [crows and related species] could have something like a theory of mind, and it would be very exciting if they did,” she says. “But right now, I don’t think we know enough to be able to say one way or the other.”
Flub factor
Research on elephant insight and chimps’ understanding of the physical world has approached the question of limits from the other direction, with scientists tweaking tests that animals normally flub to discover what specific factors let them improve.
Chimps may not understand how the physical world works well enough to attribute phenomena to underlying causes such as gravity, solidity and other such qualities — or at least that’s been a long-standing proposal. Amanda Seed of the University of St. Andrews in Scotland isn’t so sure. “The difference between human and ape folk physics may not be as clear-cut as that,” she says.
In a classic lab test, chimps seem not to grasp basic cause and effect. To coax a treat out of a device called a trap tube, an animal has to use a stick to poke the treat to one end. If nudged in the wrong direction, the food tumbles irretrievably into a hole. “Chimps appeared not very good at telling that their food would fall into a trap,” Seed says.
In one of Seed’s first chimp experiments, she redesigned the trap so the chimps could poke with their fingers instead of a stick. In a video of the new experiment, a chimp stands in front of a clear plastic box and without much ado, pokes a finger through a series of little holes, working a tidbit along in the correct direction and safely out of the box.
The problem may have been the same one faced by floundering human pool players who spend too much time watching the cue instead of the ball. Chimps may not have a different conception of surfaces and holes than people do, but rather a different capacity to focus attention or remember. Without the tool to distract them, they may absorb more of what poking around in the tube is actually doing.
Revealing such hidden animal talents requires devising the right kind of test, which often takes a bit of ingenuity. Preston Foerder of the University of Tennessee at Chattanooga was testing for insight in elephants, for instance, by putting food out of reach and providing a stick as a tool for getting it. Working with three elephants at the Smithsonian National Zoological Park in Washington, D.C., Foerder found that they readily picked up a stick. But instead of pointing it at hard-to-reach food, they banged the walls, scratched themselves and threw it around. “This was about three months of research off and on, and I was commuting from New York City to do it,” he says. “Then I had my own insight.”
Foerder moved the food and sticks outdoors and provided a cube or tub that could be moved over to the food if an elephant wanted to stand on it. In its seventh session of straining toward the food, 7-year-old elephant Kandula moved the cube into position as a stepstool and snagged some fruit (SN Online: 8/24/11).
“Elephants are more olfactory than visual,” Foerder says, and sniff with their trunks. When holding a stick, their trunks face the wrong direction for detecting what the stick is poking, and the trunk openings may even be closed. The experience points out that people may have to step outside their primate biases to get an idea of what another animal can do, Foerder says.
In the end, experiments that test animals’ cognition by determining when they succeed and when they fail may reveal more about human minds than other species’. Whether humankind truly wants to find all it looks for isn’t so clear. Homo sapiens is hardly modest about its brainpower, perhaps wanting to discover a bit of mental kinship while remaining mental kings.
【1460】
哇噻，你好好厉害哦，今天居然读完了4765词。看来，阅读也不是很难嘛。
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发表于 2013-4-22 17:34:18
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