Chapter 17. Learning and Memory
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The brain holds in mind what has just been seen by synchronizing brain waves in a working memory circuit, an animal study supported by the National Institutes of Health suggests. The more in-sync such electrical signals of neurons were in two key hubs of the circuit, the more those cells held the short-term memory of a just-seen object. Charles Gray, Ph.D., of Montana State University, Bozeman, and colleagues, report their findings Nov. 1, 2012, online, in the journal Science Express. "This work demonstrates, for the first time, that there is information about short term memories reflected in in-sync brainwaves," explained Gray. "The Holy Grail of neuroscience has been to understand how and where information is encoded in the brain. This study provides more evidence that large scale electrical oscillations across distant brain regions may carry information for visual memories," said NIMH director Thomas R. Insel, M.D. Prior to the study, scientists had observed synchronous patterns of electrical activity between the two circuit hubs after a monkey saw an object, but weren’t sure if the signals actually represent such short-term visual memories in the brain. Rather, it was thought that such neural oscillations might play the role of a traffic cop, directing information along brain highways. To find out more, Gray, Rodrigo Salazar Ph.D., and Nick Dotson of Montana State and Steven Bressler, Ph.D., at Florida Atlantic University, Boca Raton, recorded electrical signals from groups of neurons in both hubs of two monkeys performing a visual working memory task. To earn a reward, the monkeys had to remember an object — or its location — that they saw momentarily on a computer screen and correctly match it. The researchers expected to see the telltale boost in synchrony during a delay period immediately after an object disappeared from the screen, when the monkey had to hold information briefly in mind.
Keyword: Learning & Memory
Link ID: 17456 - Posted: 11.06.2012
By MARGALIT FOX Arthur R. Jensen, an educational psychologist who ignited an international firestorm with a 1969 article suggesting that the gap in intelligence-test scores between black and white students might be rooted in genetic differences between the races, died on Oct. 22 at his home in Kelseyville, Calif. He was 89. His death was confirmed by the University of California, Berkeley, where he was an emeritus professor in the Graduate School of Education. Professor Jensen was deeply interested in differential psychology, a field whose central question — What makes people behave and think differently from one another? — strikes at the heart of the age-old nature-nurture debate. Because of his empirical work in the field on the quantification of general intelligence (a subject that had long invited a more diffuse, impressionistic approach), he was regarded by many colleagues as one of the most important psychologists of his day. But a wider public remembered him almost exclusively for his 1969 article “How Much Can We Boost I.Q. and Achievement?” Published in The Harvard Educational Review, a scholarly journal, the article quickly became — and remains even now — one of the most controversial in psychology. In the article, Professor Jensen posited two types of learning ability. Level I, associative ability, entailed the rote retention of facts. Level II, conceptual ability, involved abstract thinking and problem-solving. This type, he argued, was roughly equivalent to general intelligence, denoted in psychology by the letter “g.” © 2012 The New York Times Company
By DAN HURLEY IN the back room of a suburban storefront previously occupied by a yoga studio, Nick Vecchiarello, a 16-year-old from Glen Ridge, N.J., sits at a desk across from Kathryn Duch, a recent college graduate who wears a black shirt emblazoned with the words “Brain Trainer.” Spread out on the desk are a dozen playing cards showing symbols of varying colors, shapes and sizes. Nick stares down, searching for three cards whose symbols match. “Do you see it?” Ms. Duch asks encouragingly. “Oh, man,” mutters Nick, his eyes shifting among the cards, looking for patterns. Across the room, Nathan Veloric, 23, studies a list of numbers, looking for any two in a row that add up to nine. With tight-lipped determination, he scrawls a circle around one pair as his trainer holds a stopwatch to time him. Halfway through the 50 seconds allotted to complete the exercise, a ruckus comes from the center of the room. “Nathan’s here!” shouts Vanessa Maia, another trainer. Approaching him with a teasing grin, she claps her hands like an annoying little sister. “Distraction!” she shouts. “Distraction!” There is purpose behind the silliness. Ms. Maia is challenging the trainees to stay focused on their tasks in the face of whatever distractions may be out there, whether Twitter feeds, the latest Tumblr posting or old-fashioned classroom commotion. On this Wednesday evening at the Upper Montclair, N.J., outlet of LearningRx, a chain of 83 “brain training” franchises across the United States, the goal is to improve cognitive skills. LearningRx is one of a growing number of such commercial services — some online, others offered by psychologists. Unlike traditional tutoring services that seek to help students master a subject, brain training purports to enhance comprehension and the ability to analyze and mentally manipulate concepts, images, sounds and instructions. In a word, it seeks to make students smarter. © 2012 The New York Times Company
By Gary Stix Nicotine enhances the ability to focus and remember. The alkaloid acts in a similar manner to the brain’s own signaling molecule, acetylcholine. It interacts with eponymous receptors on the surface of nerve cells to regulate signaling in the brain. The role of the nicotinic-acetylcholine receptors throughout the central nervous system is so wide-ranging that new discoveries about the molecule continue apace. A recent study published in Nature Neuroscience found that one type of nicotinic receptor acts as a key element in a cell that appears to perform a critical function in regulating memory. A team of researchers—led by one group from Uppsala University in Sweden and another from Rio Grande do Norte in Brazil—found that a type of nicotinic receptor on a cell called oriens lacunosum-moleculare (OLM-alpha 2) seems to be involved in turning on a critical circuit in the hippocampus, a brain structure involved with memory formation. “This cell has a significant influence on the incoming information to the hippocampus,” says Klas Kullander from Uppsala University. When this circuit is switched on, visual, auditory or other inputs to the hippocampus are targeted for additional processing of the incoming information, perhaps a means of flagging its importance so that it can be directed to the cerebral cortex for long-term storage of memory. The on-state of this circuit “prioritizes more intense local processing of the information,” Kullander says. “It lets the hippocampus dwell on the information longer.” © 2012 Scientific American
Keyword: Learning & Memory
Link ID: 17443 - Posted: 11.03.2012
David Cyranoski More than a decade of research hinting that magnesium supplements might boost your brain power is finally being put to the test in a small clinical trial. The research, led by biopharmaceutical company Magceutics of Hayward, California, began testing the ability of its product Magtein to boost magnesium ion (Mg2+) levels in the brain earlier this month. The trial will track whether the ions can decrease anxiety and improve sleep quality, as well as following changes in the memory and cognitive ability of participants. But critics caution that the trial in just 50 people is too small to draw definitive conclusions. Neuroscientist Guosong Liu of the Massachusetts Institute of Technology in Cambridge, who founded Magceutics, plans eventually to test whether Magtein can be used to treat a wider range of conditions, including attention deficit hyperactivity disorder (ADHD) and Alzheimer’s disease. But Liu knows that it will be difficult to convince other scientists that something as simple as a magnesium supplement can have such profound effects. It is almost “too good to be true”, he says. Many scientists contacted by Nature agreed with that sentiment. One clinical researcher cautioned against “over-excitement about a magic drug for a major disorder”. And others wonder whether the study will even be able to prove anything conclusively. “I am very sceptical that the proposed trial will provide the answer to the question being tested,” says Stephen Ferguson, a biochemist at the University of Western Ontario in London, Ontario. © 2012 Nature Publishing Group
By Daisy Yuhas We're all familiar with the feeling—waking up from a restless night only to realize that this will be a very long, sleepy day. Recent research reveals that honeybees are also sensitive to sleep deprivation, and although a cup of coffee may give you a morning buzz, the bees aren't so lucky. Neurobiologists at the Free University of Berlin have found that sleepy bees fail to remember lessons learned the day before, a finding that could help scientists discover the neural processes involved in sleep and memory formation. They present their research October 25 in the Journal of Experimental Biology. "We started with the idea that we could look for a neural substrate of learning and memory in bees, since they have a wonderful memory, can be easily trained, and we know their brain well at the neuronal level," says study co-author Randolf Menzel. After characterizing how honeybees find their way home when released in a new location, the scientists captured and then released bees in unfamiliar territory some 600 meters from their hive. In addition to tracking how long the bees needed to return home, the researchers monitored bee sleep. Bees take brief naps throughout the day in addition to longer periods of nocturnal sleep. (Snoozing bees are easy to spot because their antennae droop.) The scientists made their observations both by watching bees in person and by tracking their activity via radio-frequency devices that they glued onto some of the insects. © 2012 Scientific American
by Sara Reardon Sleeping helps us reset our brains and calm our emotions. Perhaps it can do more, though: if sleepers are exposed to odours they associate with bad memories, it appears they can lose the fear those memories bring. Previous studies have shown that sleep helps eliminate fear in general. But whether it is possible to focus this effect through the careful use of odours has not been tested in humans. Katherina Hauner and Jay Gottfried of Northwestern University in Evanston, Illinois, exposed subjects to four pictures of faces and a series of inoffensive smells such as mint. When one of the faces appeared, the volunteers got a painful electric shock. Afterwards, the researchers measured the amount of electricity conducted by the subjects' skin – a measure that goes up when afraid, because the sweat produced is a good conductor. The researchers found that conductance spiked whenever the volunteers saw the face associated with the shock. They then let half the subjects sleep, and exposed this group to variable amounts of the odour that had been presented along with the "painful" face. The next day, these volunteers were much less afraid of the face – and those with the least fear were those that had received the highest exposure to the odour while asleep. Brain scans also showed that brain areas associated with fear and with memory were less active after this exposure. © Copyright Reed Business Information Ltd.
By SINDYA N. BHANOO Most people have a moment or two they would rather not remember. The brain has two opposite ways of dealing with those memories, researchers report in a new study. The first is to simply block out the memory. The second is to recall a substitute memory. Take the case of a fight with a loved one, said Roland Benoit, a cognitive neuroscientist at the Medical Research Council Cognition and Brain Sciences Unit in Cambridge, England. “You don’t want to think about it because you want to just go on with life,” Dr. Benoit said. “You can somehow push it out, or you could try to think of something else, like maybe that nice vacation to France you had together.” Dr. Benoit and his colleagues asked study participants to associate the words “beach” and “Africa.” Then one group was told to avoid thinking about the associated words altogether. Another group was told to start thinking about the word “snorkel” in association with “beach,” rather than “Africa.” The participants were put under a functional M.R.I. scanner, and the researchers found that in the case of memory substitution, the left prefrontal cortex works in conjunction with the hippocampus, an area of the brain connecting to conscious remembering. But when an unwanted memory is simply suppressed or blocked out, the prefrontal cortex actually inhibits the functioning of the hippocampus. © 2012 The New York Times Company
Keyword: Learning & Memory
Link ID: 17406 - Posted: 10.23.2012
By Laura Sanders NEW ORLEANS — Fearful associations can be knocked back during sleep, research in mice shows. After receiving an injection of a drug, a nasty link between a scent and a painful foot shock faded as the mice slumbered. The results are preliminary but may ultimately show how to get around a roadblock in treatments for people with post-traumatic stress disorder: Traumatic associations can be weakened in a doctor’s office, but those memories can flood back when triggered by specific events in everyday life. The new finding suggests that the hazy world of sleep, lacking any particular real-world context, might be a better place to diminish such memories. Neuroscientist Asya Rolls of Stanford University and colleagues taught mice that when they smelled jasmine, a foot shock was not far behind. A day later, as the mice slept, the researchers wafted the smell over the animals, strengthening and solidifying the scary link between jasmine and pain. A day after that, the mice froze in fear when they caught a whiff of jasmine, even though the animals were in an entirely new room unassociated with the original shock. But Rolls and her team could interrupt this sleep-strengthening process with the antibiotic anisomycin, injected into the amygdala—a brain structure involved in memory storage. Before the mice were exposed to jasmine during sleep, the researchers injected some of them with the drug. The next day, these mice didn’t freeze as much as the mice that didn’t get the drug. The results suggest that during sleep, traumatic memories, such as the kind that plague people with PTSD, can be effectively weakened. © Society for Science & the Public 2000 - 2012
by Helen Thomson, New Orleans HUMANS are constantly searching for an elixir of youth - could it be that an infusion of young blood holds the key? This seems to be true for mice, at least. According to research presented this week at the Society for Neuroscience conference in New Orleans, Louisiana, giving young blood to old mice can reverse some of the effects of age-related cognitive decline. Last year, Saul Villeda, then at Stanford University in California, and colleagues showed they could boost the growth of new cells in the brains of old mice by giving them a blood infusion from young mice (Nature, doi.org/c9jwvm). "We know that blood has this huge effect on brain cells, but we didn't know if its effects extended beyond cell regeneration," he says. Now the team has tested for changes in cognition by linking the circulatory systems of young and old mice. Once the blood of each conjoined mouse had fully mixed with the other, the researchers analysed their brains. Tissue from the hippocampus of old mice given young blood showed changes in the expression of 200 to 300 genes, particularly in those involved in synaptic plasticity, which underpins learning and memory. They also found changes in some proteins involved in nerve growth. The infusion of young blood also boosted the number and strength of neuronal connections in an area of the brain where new cells do not grow. This didn't happen when old mice received old blood. © Copyright Reed Business Information Ltd.
Sitting exams and tests is often a nerve-racking experience, but being anxious beforehand may boost a candidate's grades, researchers say. A study published in the British Journal of Psychology finds being anxious only has a negative impact on results if a child's memory is poor. But if a young person has a good memory, a tendency to feel anxious is linked with getting better marks. The research assessed 96 children aged 12 to 14 in memory and anxiety tests. A questionnaire established how anxious the children usually felt, and the results were measured against their ability to perform computerised tests involving "complex" or working-memory skills. "We found that for individuals with low working-memory capacity, increases in [a tendency towards] anxiety were related to decreases in cognitive test performance," the study says. "For those with high working-memory capacity, however, the pattern of results was reversed. An increase in [a tendency towards] anxiety was linearly associated with higher test scores. "These effects were not better accounted for by gender, age, or time of testing." Poor memory The researchers say the results of the study should encourage education professionals to target help at anxious children with poor complex memory skills. BBC © 2012
Virginia Hughes On a chilly, January night in 1986, Elizabeth Ebaugh carried a bag of groceries across the quiet car park of a shopping plaza in the suburbs of Washington DC. She got into her car and tossed the bag onto the empty passenger seat. But as she tried to close the door, she found it blocked by a slight, unkempt man with a big knife. He forced her to slide over and took her place behind the wheel. The man drove aimlessly along country roads, ranting about his girlfriend's infidelity and the time he had spent in jail. Ebaugh, a psychotherapist who was 30 years old at the time, used her training to try to calm the man and negotiate her freedom. But after several hours and a few stops, he took her to a motel, watched a pornographic film and raped her. Then he forced her back into the car. She pleaded with him to let her go, and he said that he would. So when he stopped on a bridge at around 2 a.m. and told her to get out, she thought she was free. Then he motioned for her to jump. “That's the time where my system, I think, just lost it,” Ebaugh recalls. Succumbing to the terror and exhaustion of the night, she fainted. Ebaugh awoke in freefall. The man had thrown her, limp and handcuffed, off the bridge four storeys above a river reservoir. When she hit the frigid water, she turned onto her back and started kicking. “At that point, there was no part of me that thought I wasn't going to make it,” she says. Few people will experience psychological and physical abuse as terrible as the abuse Ebaugh endured that night. But extreme stress is not unusual. In the United States, an estimated 50–60% of people will experience a traumatic event at some point in their lives, whether through military combat, assault, a serious car accident or a natural disaster. Acute stress triggers an intense physiological response and cements an association in the brain's circuits between the event and fear. If this association lingers for more than a month, as it does for about 8% of trauma victims, it is considered to be post-traumatic stress disorder (PTSD). The three main criteria for diagnosis are recurring and frightening memories, avoidance of any potential triggers for such memories and a heightened state of arousal. © 2012 Nature Publishing Group,
By Susan Milius A dollop of living yellow ooze has aced a test of navigation, showing that you don’t really need a mind to make spatial memories. The egg-yolk-colored slime mold Physarum polycephalum is a single cell without any nervous system. But this blob of a creature uses its slime trails as a form of external spatial memory, says complex systems biologist Chris R. Reid of the University of Sydney. Smears of goo left behind as a slime mold crawls act as records of past paths. Given a choice, slime molds won’t crawl over their old slime, Reid and his colleagues found. These simple external “memories” work quite well. When lured into a U-shaped dead-end in front of a sugar treat, slime molds were able to escape. Instead of just throbbing futilely against the closed end of the U or crawling around in circles, 39 out of 40 managed to ooze their way back out of the blind alley and creep to the treat by an outside route, Reid and his colleagues report October 8 in the Proceedings of the National Academy of Sciences. “It’s the first time any spatial memory system has been found in an organism without a brain,” Reid says. Ants, which Reid also studies, lay trails of scents as they scurry to food sources, and these scents can function as external memories of the whole colony. Ants do have brains though. © Society for Science & the Public 2000 - 2012
Keyword: Learning & Memory
Link ID: 17353 - Posted: 10.11.2012
By Gregory Thomas, During an introductory psychology course at Britain’s University of Essex in 2009, Arnold Wilkins asked his class to participate in a quick experiment. Wilkins projected two images on a wall and asked students to write down whether they found either of them disturbing. One was a photograph of a woody landscape. The other was a close-up of a lotus-flower seedpod — a flat-faced pod pocked with small holes. Most of the students were unmoved, but one, freshman An Le, recalls being both transfixed and revolted by the lotus image. “It felt like I was in shock,” he says. Le is far from alone in his response. Thousands of people claim to suffer trypophobia, a term derived from the Greek “trypo,” which means punching, drilling or boring holes. It refers to an irrational fear of clusters of small holes, such as beehives, ant holes and even bubbles in a pancake on the griddle or air pockets in a chocolate bar. On Web sites and blogs, self-diagnosed trypophobes share tales of vomiting, sleep loss and anxiety attacks at the sight of such objects as honeycombs and rotting wood. They say the fears are haunting and disruptive of their daily lives. But the medical world hasn’t yet embraced the phobia as real. Trypophobia isn’t listed in any major dictionary or in the Diagnostic and Statistical Manual of Mental Disorders. Attempts to add trypophobia to the Oxford English Dictionary and even to establish a Wikipedia page have been rebuffed because there hasn’t been any research published on the subject. A Wikipedia editor who deleted an entry on trypophobia in 2009 noted that trypophobia is “likely hoax and borderline patent nonsense.” © 1996-2012 The Washington Post
Clint Witchalls James R. Flynn is Professor Emeritus at the University of Otago, New Zealand. Flynn researches intelligence and is best known for the discovery that, over the past century, IQs have been rising at a rate of about 3 points per decade (the Flynn-effect). In advance of his new book on the subject, Clint Witchalls asked him about this and some of Professor Flynn's more recent research findings: Clint Witchalls: How has our way of thinking and of solving problems changed over the past century? James R. Flynn: Today we take it for granted that using logic on the abstract is an ability we want to cultivate and we are interested in the hypothetical. People from 1900 were not scientifically oriented but utilitarian and they used logic, but to use it on the hypothetical or on abstractions was foreign to them. Alexander Luria [a Soviet psychologist] went to talk to headmen in villages in rural Russia and he said to them: "Where there is always snow, bears are white. At the North Pole there is always snow, what colour are the bears there?" And they said: "I've only seen brown bears." And he said: "What do my words convey?" And they said: "Such a thing as not to be settled by words but by testimony." They didn't settle questions of fact by logic, they settled them by experience. Your research found that we have gained 30 points on IQ tests in a century. What is the reason? The ultimate cause of why IQs are rising is the industrial revolution. The proximate cause is how our minds differ from people in 1900 when in the test room. And the intermediate causes, of course, are more cognitively demanding work roles, more cognitively demanding leisure, more formal schooling, and smaller families. © independent.co.uk
By GRETCHEN REYNOLDS Can you improve your body’s ability to remember by making it move? That rather odd-seeming question stimulated researchers at the University of Copenhagen to undertake a reverberant new examination of just how the body creates specific muscle memories and what role, if any, exercise plays in the process. To do so, they first asked a group of young, healthy right-handed men to master a complicated tracking skill on a computer. Sitting before the screen with their right arm on an armrest and a controller similar to a joystick in their right hand, the men watched a red line squiggle across the screen and had to use the controller to trace the same line with a white cursor. Their aim was to remain as close to the red squiggle as possible, a task that required input from both the muscles and the mind. The men repeated the task multiple times, until the motion necessary to track the red line became ingrained, almost automatic. They were creating a short-term muscle memory. The term “muscle memory” is, of course, something of a misnomer. Muscles don’t make or store memories. They respond to signals from the brain, where the actual memories of any particular movement are formed and filed away. But muscle memory — or “motor memory,” as it is more correctly referred to among scientists — exists and can be quite potent. Learn to ride a bicycle as a youngster, abandon the pastime and, 20 years later, you’ll be able to hop on a bicycle and pedal off. Copyright 2012 The New York Times Company
Keyword: Learning & Memory
Link ID: 17304 - Posted: 09.26.2012
By Gary Stix Market researcher SharpBrains has predicted that the brain fitness industry will range anywhere from $2 billion to $8 billion in revenues by 2015. That’s a wide swath, but the companies that sell brain-tuning software could conceivably hit at least the low end of their sales target by then. The question that persists is whether any of these games and exercises actually enhance the way your brain works, whether it be memory, problem solving or the speed with which you execute a mental task. True, study participants often get better at doing an exercise that is supposedly related to a given facet of cognition. But the ability to master a game or ace a psych test often doesn’t translate into better cognition when specific measures of intelligence are assayed later. One area of research that has shown some promise relates to a method of boosting the mental scratchpad of working memory— keeping in your head a telephone number long enough to dial, for instance. Some studies have demonstrated that a particular technique to energize working memory betters the reasoning and problem-solving abilities known as fluid intelligence. Yet two new studies have now called into question the earlier research on working memory. A recent online publication in the Journal of Experimental Psychology led by a group at the Georgia Institute of Technology showed that 20 sessions on a working memory task did not did not result in a later acing of tests of cognitive ability. Similarly, a group at Case Western Reserve University tried the same “dual n-back test” and published a report in the journal Intellgence that found that better scores did not produce higher tallies for working memory and fluid intelligence. An n-back test requires keeping track of a number, letter or image “n” places back. A dual n-back demands the simultaneous remembering of both a visual and auditory cue perceived a certain number of places back. © 2012 Scientific American
Keyword: Learning & Memory
Link ID: 17303 - Posted: 09.26.2012
by Douglas Heaven Ever wish you could make better choices? That could one day be possible thanks to an electronic brain implant that can enhance short-term memory and decision-making in primates. The implant can also restore these functions in an animal model of Alzheimer's disease and other types of brain damage, paving the way for the development of new treatments for people with these conditions. Sam Deadwyler at Wake Forest University School of Medicine in Winston-Salem, North Carolina, and colleagues have previously shown that a neural implant can restore some motor and sensory functions in rats. Now they have used a similar implant to stimulate higher-level thinking in monkeys. During normal brain function, neurons "fire" when they receive an input from another neuron via the connection between them, called a synapse. The spatial and temporal pattern of this activity – where and when the neurons fire – can be detected and recorded. To find out if it is possible to hijack and then retune these patterns of activity, Deadwyler's team first trained five rhesus macaques to perform a task that tests their attention, short-term memory and decision-making skills. First, the monkeys were shown a random image from a pool of 5000. The image was then blanked out for an interval of 1 to 90 seconds, before reappearing in a different position, alongside up to seven other images. If the monkey selected the original image once it reappeared it was rewarded with juice. © Copyright Reed Business Information Ltd.
Remember the game "telephone"? Someone starts by saying a sentence to the person next to them. That person then turns to someone else and repeats what they heard. Somehow, by the time the sentence gets to the last person in line, it's all mixed up and barely resembles the original. Apparently our memories operate in the same way. A study published recently in the Journal of Neuroscience looks at how we retrieve memories. It's a well-known phenomenon that retrieval is good for memory - the more you remember something, the longer you'll remember it for. The catch, researchers have discovered, is that each time you retrieve a memory you forget or add small things to it, and the next time you recall the information, you'll remember what you remembered. "Our memories aren’t like a photograph," says lead study author Donna Bridge. "We mix up details, we forget things. We’re likely to remember this incorrect information just as much as we are the correct (memory)." In other words, the more you recall an event, the more distorted your memory of that event may be. Bridge, a postdoctoral fellow at Northwestern University's Feinberg School of Medicine, asked 12 participants to take a memory test on three subsequent days. The first day, study participants repeatedly placed 180 objects in an assigned location - different for each one - on a computer screen grid. The second day they were asked to place those objects in the same positions. Twenty-four hours later, they did it again. © 2012 Cable News Network
Keyword: Learning & Memory
Link ID: 17282 - Posted: 09.22.2012
by Virginia Morell Imagine hearing a distant roll of thunder and wondering what caused it. Even asking that question is a sign that you, like all humans, can perform a type of sophisticated thinking known as "causal reasoning"—inferring that mechanisms you can't see may be responsible for something. But humans aren't alone in this ability: New Caledonian crows can also reason about hidden mechanisms, or "causal agents," a team of scientists report today in the Proceedings of the National Academy of Sciences. It's the first time that this cognitive ability has been experimentally demonstrated in a species other than humans, and the method may help scientists understand how this type of reasoning evolved, the researchers say. Causal reasoning is "one of the most powerful human abilities," says Alison Gopnik, a psychologist at the University of California, Berkeley, who was not involved in the study. "It's at the root of our understanding of the world and one another." Indeed, it is the key mental ability for many things humans do, including inventing, making, and using tools. We develop this ability early in life: A 2007 study in Developmental Psychology reported that human infants as young as 7 months old understand that when a beanbag is tossed from behind a screen, something or someone must have thrown it. The infants infer that a "causal agent" must be involved in the motion of the flying beanbag. But why should this ability be limited to humans? "It seems like it would make good sense for crows and many other animals to be able to distinguish between the wind rustling tree limbs and an unseen animal crashing through the canopy," says Alex Taylor, an evolutionary psychologist at the University of Auckland in New Zealand and the lead author of the new study. Because New Caledonian crows are also inventive and skillful tool-users, Taylor and his colleagues thought the birds might have causal reasoning skills similar to those of humans. © 2010 American Association for the Advancement of Science