Chapter 17. Learning and Memory
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By PAM BELLUCK What happens to forgotten memories — old computer passwords, friends’ previous phone numbers? Scientists have long held two different theories. One is that memories do not diminish but simply get overshadowed by new memories. The other is that older memories become weaker, that pulling to mind new passwords or phone numbers degrades old recollections so they do not interfere. The difference could be significant. If old memories stay strong and are merely papered over by new ones, they may be easier to recover. That could be positive for someone trying to remember an acquaintance’s name, but difficult for someone trying to lessen memories of abuse. It could suggest different strategies for easing traumatic memories, evaluating witness testimony about crimes, or helping students study for tests. Now, a study claims to provide evidence of memory’s weakening by showing that people’s ability to remember something and the pattern of brain activity that thing generates both appear to diminish when a competing memory gets stronger. Demonstrating sophisticated use of brain scans in memory research, authors of the study, published Monday in the journal Nature Neuroscience, appear to have identified neural fingerprints of specific memories, distinguishing brain activity patterns produced when viewing a picture of a necklace, say, from a picture of binoculars or other objects. The experiment, conducted by scientists in Birmingham and Cambridge, England, involved several stages with 24 participants first trained to associate words to two unrelated black and white pictures from lists of famous people, ordinary objects or scenes. © 2015 The New York Times Company
Keyword: Learning & Memory
Link ID: 20695 - Posted: 03.17.2015
By BENEDICT CAREY Behind all those canned compliments for older adults — spry! wily! wise! — is an appreciation for something that scientists have had a hard time characterizing: mental faculties that improve with age. Knowledge is a large part of the equation, of course. People who are middle-aged and older tend to know more than young adults, by virtue of having been around longer, and score higher on vocabulary tests, crossword puzzles and other measures of so-called crystallized intelligence. Still, young adults who consult their elders (mostly when desperate) don’t do so just to gather facts, solve crosswords or borrow a credit card. Nor, generally, are they looking for help with short-term memory or puzzle solving. Those abilities, called fluid intelligence, peak in the 20s. No, the older brain offers something more, according to a new paper in the journal Psychological Science. Elements of social judgment and short-term memory, important pieces of the cognitive puzzle, may peak later in life than previously thought. The postdoctoral fellows Joshua Hartshorne of M.I.T. and Laura Germine of Harvard and Massachusetts General Hospital analyzed a huge trove of scores on cognitive tests taken by people of all ages. The researchers found that the broad split in age-related cognition — fluid in the young, crystallized in the old — masked several important nuances. “This dichotomy between early peaks and later peaks is way too coarse,” Dr. Hartshorne said. “There are a lot more patterns going on, and we need to take those into account to fully understand the effects of age on cognition.” The new paper is hardly the first challenge to the scientific literature on age-related decline, and it won’t be the last. A year ago, German scientists argued that cognitive “deficits” in aging were caused largely by the accumulation of knowledge — that is, the brain slows down because it has to search a larger mental library of facts. That idea has stirred some debate among scientists. Experts said the new analysis raised a different question: Are there distinct, independent elements of memory and cognition that peak at varying times of life? © 2015 The New York Times Company
By Maggie Fox Teenagers who use marijuana heavily grow up to have poor memories and also have brain abnormalities, a new study shows. The study cannot say which came first — the brain structure differences or the pot use. But it suggests there could be long-term effects of heavy marijuana use. A team at Northwestern University looked at 97 volunteers with and without mental illness. The dope smokers said they'd used marijuana daily starting at age 16 or 17, and said they had not used other drugs. The daily marijuana users had an abnormally shaped hippocampus and performed about 18 percent more poorly on long-term memory tasks, the researchers reported in the journal Hippocampus. The hippocampus is a part of the brain used in storing long-term memory. "The memory processes that appear to be affected by cannabis are ones that we use every day to solve common problems and to sustain our relationships with friends and family," said Dr. John Csernansky, who worked on the study. Previous research by the same Northwestern team showed heavy pot smokers had poor short-term and working memory and abnormally shaped brain structures including the striatum, globus pallidus and thalamus. "It is possible that the abnormal brain structures reveal a pre-existing vulnerability to marijuana abuse," Matthew Smith, who led the study, said in a statement.
By Douglas Starr In 1906, Hugo Münsterberg, the chair of the psychology laboratory at Harvard University and the president of the American Psychological Association, wrote in the Times Magazine about a case of false confession. A woman had been found dead in Chicago, garroted with a copper wire and left in a barnyard, and the simpleminded farmer’s son who had discovered her body stood accused. The young man had an alibi, but after questioning by police he admitted to the murder. He did not simply confess, Münsterberg wrote; “he was quite willing to repeat his confession again and again. Each time it became richer in detail.” The young man’s account, he continued, was “absurd and contradictory,” a clear instance of “the involuntary elaboration of a suggestion” from his interrogators. Münsterberg cited the Salem witch trials, in which similarly vulnerable people were coerced into self-incrimination. He shared his opinion in a letter to a Chicago nerve specialist, which made the local press. A week later, the farmer’s son was hanged. Münsterberg was ahead of his time. It would be decades before the legal and psychological communities began to understand how powerfully suggestion can shape memory and, in turn, the course of justice. In the early nineteen-nineties, American society was recuperating from another panic over occult influence; Satanists had replaced witches. One case, the McMartin Preschool trial, hinged on nine young victims’ memories of molestation and ritual abuse—memories that they had supposedly forgotten and then, after being interviewed, recovered. The case fell apart, in 1990, because the prosecution could produce no persuasive evidence of the victims’ claims. A cognitive psychologist named Elizabeth Loftus, who had consulted on the case, wondered whether the children’s memories might have been fabricated—in Münsterberg’s formulation, involuntarily elaborated—rather than actually recovered.
Keyword: Learning & Memory
Link ID: 20679 - Posted: 03.12.2015
Mo Costandi Neuroscientists in France have implanted false memories into the brains of sleeping mice. Using electrodes to directly stimulate and record the activity of nerve cells, they created artificial associative memories that persisted while the animals snoozed and then influenced their behaviour when they awoke. Manipulating memories by tinkering with brain cells is becoming routine in neuroscience labs. Last year, one team of researchers used a technique called optogenetics to label the cells encoding fearful memories in the mouse brain and to switch the memories on and off, and another used it to identify the cells encoding positive and negative emotional memories, so that they could convert positive memories into negative ones, and vice versa. The new work, published today in the journal Nature Neuroscience, shows for the first time that artificial memories can be implanted into the brains of sleeping animals. It also provides more details about how populations of nerve cells encode spatial memories, and about the important role that sleep plays in making such memories stronger. Karim Benchenane of the French National Centre for Scientific Research (CNRS) in Paris and his colleagues implanted electrodes into the brains of 40 mice, targeting the medial forebrain bundle (MFB), a component of the reward circuitry, and the CA1 region of the hippocampus, which contains at least three different cell types that encode the memories needed for spatial navigation. © 2015 Guardian News and Media Limited
by Penny Sarchet For some of us, it might have been behind the bikeshed. Not so the African cotton leafworm moth (Spodoptera littoralis), which can choose any one of a vast number of plant species to mate on. But these moths remember their first time, returning to the same species in search of other mates. In the wild, this moth feeds and mates on species from as many as 40 different plant families. That much choice means there's usually something available to eat, but selecting and remembering the best plants is tricky. So, recalling what you ate as a larva, or where you first copulated, may help narrow down which plants provide better quality food or are more likely to attract other potential mates. Magali Proffit and David Carrasco of the Swedish University of Agricultural Sciences in Alnarp and their colleagues have discovered that this moth's first mating experience shapes its future preferences. These moths have an innate preference for cotton plants over cabbage. But when the researchers made them mate for the first time on cabbage, the moths later showed an increased preference for mating or laying eggs on this plant. Further experiments revealed that moths didn't just favour plants they were familiar with, even in combination with a sex pheromone – mating had to be involved. © Copyright Reed Business Information Ltd.
Lights, sound, action: we are constantly learning how to incorporate outside sensations into our reactions in specific situations. In a new study, brain scientists have mapped changes in communication between nerve cells as rats learned to make specific decisions in response to particular sounds. The team then used this map to accurately predict the rats’ reactions. These results add to our understanding of how the brain processes sensations and forms memories to inform behavior. “We’re reading the memories in the brain,” said Anthony Zador, M.D., Ph.D., professor at Cold Spring Harbor Laboratory, New York, and senior author of the study, published in Nature. The work was funded by the National Institutes of Health and led by Qiaojie Xiong, Ph.D., a former postdoctoral researcher in Dr. Zador’s laboratory. “For decades scientists have been trying to map memories in the brain,” said James Gnadt, Ph.D., a program director at the National Institute of Neurological Disorders and Stroke (NINDS), one of the NIH institutes that funded the study. “This study shows that scientists can begin to pinpoint the precise synapses where certain memories form and learning occurs.” The communication points, or synapses, that Dr. Zador’s lab studied were in the striatum, an integrating center located deep inside the brain that is known to play an important role in coordinating the translation of thoughts and sensations into actions. Problems with striatal function are associated with certain neurological disorders such as Huntington’s disease in which affected individuals have severely impaired skill learning.
Elizabeth Gibney DeepMind, the Google-owned artificial-intelligence company, has revealed how it created a single computer algorithm that can learn how to play 49 different arcade games, including the 1970s classics Pong and Space Invaders. In more than half of those games, the computer became skilled enough to beat a professional human player. The algorithm — which has generated a buzz since publication of a preliminary version in 2013 (V. Mnih et al. Preprint at http://arxiv.org/abs/1312.5602; 2013) — is the first artificial-intelligence (AI) system that can learn a variety of tasks from scratch given only the same, minimal starting information. “The fact that you have one system that can learn several games, without any tweaking from game to game, is surprising and pretty impressive,” says Nathan Sprague, a machine-learning scientist at James Madison University in Harrisonburg, Virginia. DeepMind, which is based in London, says that the brain-inspired system could also provide insights into human intelligence. “Neuroscientists are studying intelligence and decision-making, and here’s a very clean test bed for those ideas,” says Demis Hassabis, co-founder of DeepMind. He and his colleagues describe the gaming algorithm in a paper published this week (V. Mnih et al. Nature 518, 529–533; 2015. Games are to AI researchers what fruit flies are to biology — a stripped-back system in which to test theories, says Richard Sutton, a computer scientist who studies reinforcement learning at the University of Alberta in Edmonton, Canada. “Understanding the mind is an incredibly difficult problem, but games allow you to break it down into parts that you can study,” he says. But so far, most human-beating computers — such as IBM’s Deep Blue, which beat chess world champion Garry Kasparov in 1997, and the recently unveiled algorithm that plays Texas Hold ’Em poker essentially perfectly (see Nature http://doi.org/2dw; 2015)—excel at only one game. © 2015 Nature Publishing Group
Charles F. Zorumski It is indeed possible for a person to get intoxicated and not remember what she or he did. This state is called a “blackout” or, more precisely, a “memory blackout.” During a blackout a person is intoxicated but awake and interacting with the environment in seemingly meaningful ways, such as holding a conversation or driving a car. After the period of intoxication, usually the next day, the person has no or, at best, vague recall for events that occurred while inebriated. At times, being in this state can have disastrous consequences, such as waking up in an unknown or unsafe place, losing personal possessions or participating in risky behaviors. On the neural level, a blackout is a period of anterograde amnesia. That is, a person's ability to form new memories becomes impaired. Although a person does not lose previously learned information, he or she may also find it more difficult to recall certain facts while intoxicated. Yet once a person sobers up, his or her memory and ability to learn new information are not permanently affected. How alcohol, or ethanol, produces a memory blackout is not completely understood. It is clear, however, that alcohol can impair a process in brain cells called long-term potentiation (LTP), a cellular mechanism thought to underlie memory formation, particularly in the hippocampus. © 2015 Scientific American
by Catherine Lawson Over the last six years Adam Gazzaley's research has undergone a transformation. He's moved from studying how the brain works, to studying the brain as it ages, then into the domain of applying methodology he's developed to improve the brain's functions. At WIRED Health 2015 he'll outline his vision of the future, one where "we're thinking about software and hardware as medicine". In particular, Gazzaley plans to talk to the WIRED Health audience about video games "that are custom-designed to challenge the brain in a very particular way". Gazzaley's team at University of California, San Francisco previously demonstrated that a custom-designed video game can be highly effective in treating a specific cognitive deficit. They developed NeuroRacer, a driving game aimed at improving multi-tasking skills in older people. The success of NeuroRacer propelled Gazzaley into new partnerships, giving him access to resources that further advance his games development program into areas like motion capture and virtual reality. He's excited about coupling his games with mobile devices that will allow them to function outside the lab. Gazzaley will talk about four new games he's working on, in particular a meditation-inspired one. Meditrain is the product of his collaboration with Buddhist author and teacher Jack Kornfield. Developed for the iPad, he hopes to demonstrate part of it at WIRED Health.
Keyword: Learning & Memory
Link ID: 20593 - Posted: 02.19.2015
Carl Zimmer In 2010, a graduate student named Tamar Gefen got to know a remarkable group of older people. They had volunteered for a study of memory at the Feinberg School of Medicine at Northwestern University. Although they were all over age 80, Ms. Gefen and her colleagues found that they scored as well on memory tests as people in their 50s. Some complained that they remembered too much. She and her colleagues referred to them as SuperAgers. Many were also friends. “A couple tried to set me up with their grandsons,” Ms. Gefen said. She was impressed by their resilience and humor: “It takes wisdom to a whole new level.” Recently, Ms. Gefen’s research has taken a sharp turn. At the outset of the study, the volunteers agreed to donate their brains for medical research. Some of them have died, and it has been Ms. Gefen’s job to look for anatomical clues to their extraordinary minds. “I had this enormous privilege I can’t even begin to describe,” she said. “I knew them and tested them in life and in death. At the end, I was the one looking at them through a microscope.” Ms. Gefen and her colleagues are now starting to publish the results of these post-mortem studies. Last month in The Journal of Neuroscience, the scientists reported that one of the biggest differences involves peculiar, oversize brain cells known as von Economo neurons. SuperAgers have almost five times as many of them as other people. Learning what makes these brains special could help point researchers to treatments for Alzheimer’s disease and other kinds of mental decline. But it is hard to say how an abundance of von Economo neurons actually helps the brain. © 2015 The New York Times Company
By Amy Ellis Nutt When we tell stories about our lives, most of us never have our memories questioned. NBC's Brian Williams, like other high-profile people in the past, is finding out what happens when questions arise. Williams's faux pas – retelling a story of his helicopter coming under fire in Iraq a dozen years ago when it was actually the helicopter flying ahead of him – was much like Hillary Rodham Clinton's during the 2008 presidential campaign. Her story was about coming under fire during a visit to an airfield in Bosnia 12 years earlier. George W. Bush also misremembered when, on several occasions, he told audiences that on 9/11 he watched the first plane fly into the north tower of the World Trade Center on TV, just before entering that classroom in Florida to read a book to school kids. In each case, these were highly emotional moments. Williams's helicopter made an emergency landing in the desert behind the aircraft that was hit; Clinton was made to don a flak jacket and was told her airplane might not be able to land at the airport in Bosnia because of sniper fire in the area; and Bush was told by an aide about the first crash into World Trade Center just before entering the classroom. That each of those memories was false created huge public relations headaches for Clinton and Williams. But the fact is that false memories are not that uncommon, especially when they involve highly emotional events. Scientists have been telling us for years that memory of autobiographical events, also known as episodic memory, is pliable and even unreliable. The consensus from neuroimaging studies and laboratory experiments is that episodic memory is not like replaying a film but more like reconstructing an event from bits and pieces of information. Memories are stored in clusters of neurons called engrams, and the proteins responsible for storing those memories, scientists say, are modified and changed just by the reconstruction process of remembering.
Keyword: Learning & Memory
Link ID: 20566 - Posted: 02.09.2015
By Kate Baggaley Stem cells can help heal long-term brain damage suffered by rats blasted with radiation, researchers report in the Feb. 5 Cell Stem Cell. The treatment allows the brain to rebuild the insulation on its nerve cells so they can start carrying messages again. The researchers directed human stem cells to become a type of brain cell that is destroyed by radiation, a common cancer treatment, then grafted the cells into the brains of irradiated rats. Within a few months, the rats’ performance on learning and memory tests improved. “This technique, translated to humans, could be a major step forward for the treatment of radiation-induced brain … injury,” says Jonathan Glass, a neurologist at Emory University in Atlanta. Steve Goldman, a neurologist at the University of Rochester in New York, agrees that the treatment could repair a lot of the damage caused by radiation. “Radiation therapy … is very effective, but the problem is patients end up with severe disability,” he says. “Fuzzy thinking, a loss in higher intellectual functions, decreases in memory — all those are part and parcel of radiation therapy to the brain.” For children, the damage can be profound. “Those kids have really significant detriments in their adult IQs,” Goldman says. Radiation obliterates cells that mature into oligodendrocytes, a type of cell that coats the message-carrying part of nerve cells with insulation. Without that cover, known as the myelin sheath, nerve cells can’t transmit information, leading to memory and other brain problems. © Society for Science & the Public 2000 - 2015
By Maria Konnikova R. T. first heard about the Challenger explosion as she and her roommate sat watching television in their Emory University dorm room. A news flash came across the screen, shocking them both. R. T., visibly upset, raced upstairs to tell another friend the news. Then she called her parents. Two and a half years after the event, she remembered it as if it were yesterday: the TV, the terrible news, the call home. She could say with absolute certainty that that’s precisely how it happened. Except, it turns out, none of what she remembered was accurate. R. T. was a student in a class taught by Ulric Neisser, a cognitive psychologist who had begun studying memory in the seventies. Early in his career, Neisser became fascinated by the concept of flashbulb memories—the times when a shocking, emotional event seems to leave a particularly vivid imprint on the mind. William James had described such impressions, in 1890, as “so exciting emotionally as almost to leave a scar upon the cerebral tissues.” The day following the explosion of the Challenger, in January, 1986, Neisser, then a professor of cognitive psychology at Emory, and his assistant, Nicole Harsch, handed out a questionnaire about the event to the hundred and six students in their ten o’clock psychology 101 class, “Personality Development.” Where were the students when they heard the news? Whom were they with? What were they doing? The professor and his assistant carefully filed the responses away. In the fall of 1988, two and a half years later, the questionnaire was given a second time to the same students. It was then that R. T. recalled, with absolute confidence, her dorm-room experience. But when Neisser and Harsch compared the two sets of answers, they found barely any similarities.
Keyword: Learning & Memory
Link ID: 20548 - Posted: 02.05.2015
Criminal psychopaths learn to respond differently to punishment cues than others in jail and may need more reward-focused treatments, new research suggests. Criminals such as Paul Bernardo, Ted Bundy and Clifford Olson, who scored high on psychopathy checklists, were known to be callous and unemotional. Psychopaths derive pleasure from being manipulative and use premeditated aggression to get what they want with no regard for those who are hurt. The search for what makes them tick has shown some physical differences in their brains such as reductions in grey matter. Now researchers in London, Montreal and Bethseda, Md., have used functional MRI imaging to assess how the brains of 12 violent criminals with psychopathy, 20 violent criminals with antisocial personality disorder but not psychopathy (such as those with a history of impulsivity and risk-taking), and 18 healthy people who were not criminals responded differently to rewards and punishment. "In the room with them, there's the sense that the weight of what they've done and the deleterious effect this is having on their lives doesn't really hold for them," said Dr. Nigel Blackwood of King's College London, a senior author of the paper in Wednesday's issue of Lancet Psychiatry. It's only at the moment in the scanner when the sanction of lost points cues them to change their behaviour that the differences between violent psychopaths and those with antisocial personality disorder appear. ©2015 CBC/Radio-Canada
Alison Abbott If you have to make a complex decision, will you do a better job if you absorb yourself in, say, a crossword puzzle instead of ruminating about your options? The idea that unconscious thought is sometimes more powerful than conscious thought is attractive, and echoes ideas popularized by books such as writer Malcolm Gladwell’s best-selling Blink. But within the scientific community, ‘unconscious-thought advantage’ (UTA) has been controversial. Now Dutch psychologists have carried out the most rigorous study yet of UTA — and find no evidence for it. Their conclusion, published this week in Judgement and Decision Making, is based on a large experiment that they designed to provide the best chance of capturing the effect should it exist, along with a sophisticated statistical analysis of previously published data1. The report adds to broader concerns about the quality of psychology studies and to an ongoing controversy about the extent to which unconscious thought in general can influence behaviour. “The bigger debate is about how clever our unconscious is,” says cognitive psychologist David Shanks of University College London. “This carefully constructed paper makes a great contribution.” Shanks published a review last year that questioned research claiming that various unconscious influences, including UTA, affect decision making2. © 2015 Nature Publishing Group
By BENEDICT CAREY The surge of emotion that makes memories of embarrassment, triumph and disappointment so vivid can also reach back in time, strengthening recall of seemingly mundane things that happened just beforehand and that, in retrospect, are relevant, a new study has found. The report, published Wednesday in the journal Nature, suggests that the television detective’s standard query — “Do you remember any unusual behavior in the days before the murder?” — is based on solid brain science, at least in some circumstances. The findings fit into the predominant theory of memory: that it is an adaptive process, continually updating itself according to what knowledge may be important in the future. The new study suggests that human memory has, in effect, a just-in-case file, keeping seemingly trivial sights, sounds and observations in cold storage for a time in case they become useful later on. But the experiment said nothing about the effect of trauma, which shapes memory in unpredictable ways. Rather, it aimed to mimic the arousals of daily life: The study used mild electric shocks to create apprehension and measured how the emotion affected memory of previously seen photographs. In earlier work, researchers had found plenty of evidence in animals and humans of this memory effect, called retroactive consolidation. The new study shows that the effect applies selectively to related, relevant information. “The study provides strong evidence for a specific kind of retroactive enhancement,” said Daniel L. Schacter, a professor of psychology at Harvard who was not involved in the research. “The findings go beyond what we’ve found previously in humans.” © 2015 The New York Times Company
Research suggests that only 20–30% of drug users actually descend into addiction — defined as the persistent seeking and taking of drugs even in the face of dire personal consequences. Why are some people who use drugs able to do so without turning into addicts, while others continue to abuse, even when the repercussions range from jail time to serious health problems? In a comprehensive review in the European Journal of Neuroscience, Barry Everitt outlines the neural correlates and learning-based processes associated with the transition from drug use, to abuse, to addiction. Drug seeking begins as a goal-directed behavior, with an action (finding and taking drugs) leading to a particular outcome (the drug high). This type of associative learning is mediated by the dorsomedial region of the striatum, the area of the brain that is associated with reward processing, which functions primarily through the neurotransmitter dopamine. In this kind of learning, devaluing the outcome (by decreasing the potency of the drug, for example) tends to decrease the pursuit of the action. When the high is not what it used to be, the motivation to continue seeking it out decreases. However, in long-term abusers, this devalued outcome does not reduce the action — indeed, researchers have found that in cases of chronic drug use, a parallel associative learning process eventually comes to the fore. This process is one of stimulus–response; the conditioned stimuli in this case are the various environmental cues — the sight of the powdery white stuff, the smell of burning aluminum foil — that users associate with getting high and that compel them to seek out drugs. © Association for Psychological Science
It is now one hundred years since drugs were first banned - and all through this long century of waging war on drugs, we have been told a story about addiction, by our teachers, and by our governments. This story is so deeply ingrained in our minds that we take it for granted. It seems obvious. It seems manifestly true. Until I set off three and a half years ago on a 30,000-mile journey for my book 'Chasing The Scream - The First And Last Days of the War on Drugs' to figure out what is really driving the drug war, I believed it too. But what I learned on the road is that almost everything we have been told about addiction is wrong - and there is a very different story waiting for us, if only we are ready to hear it. If we truly absorb this new story, we will have to change a lot more than the drug war. We will have to change ourselves. I learned it from an extraordinary mixture of people I met on my travels. From the surviving friends of Billie Holiday, who helped me to learn how the founder of the war on drugs stalked and helped to kill her. From a Jewish doctor who was smuggled out of the Budapest ghetto as a baby, only to unlock the secrets of addiction as a grown man. From a transsexual crack dealer in Brooklyn who was conceived when his mother, a crack-addict, was raped by his father, an NYPD officer. From a man who was kept at the bottom of a well for two years by a torturing dictatorship, only to emerge to be elected President of Uruguay and to begin the last days of the war on drugs. ©2015 TheHuffingtonPost.com, Inc.
Closing your eyes when trying to recall events increases the chances of accuracy, researchers at the University of Surrey suggest. Scientists tested people's ability to remember details of films showing fake crime scenes. They hope the studies will help witnesses recall details more accurately when questioned by police. They say establishing a rapport with the person asking the questions can also help boost memory. Writing in the journal Legal and Criminological Psychology, scientists tested 178 participants in two separate experiments. In the first, they asked volunteers to watch a film showing an electrician entering a property, carrying out work and then stealing a number of items. Volunteers were then questioned in one of four groups. People were either asked questions with their eyes open or closed, and after a sense of rapport had been built with the interviewer or no attempt had been made to create a friendly introduction. People who had some rapport with their interviewer and had their eyes shut throughout questioning answered three-quarters of the 17 questions correctly. But those who did not have a friendly introduction with the interviewer and had their eyes open answered 41% correctly. The analysis showed that eye closing had the strongest impact on remembering details correctly ,but that feeling comfortable during the interview also helped. In the second experiment, people were asked to remember details of what they had heard during a mock crime scene. © 2015 BBC