Links for Keyword: Emotions
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By Rachel Feltman Fear is one of our most basic evolutionary instincts, a sudden physical jolt to help us react to danger more quickly. In the modern world, fear often seems excessive -- in the absence of wild animals to flee, we're left screaming over roller coasters and scary movies. But for at least one woman, fear is unobtainable. And while she lives a normal life, her fearlessness is actually a handicap. The researchers who study her keep her closely guarded, using the code-name "SM" when publishing papers about her brave brainpower. And until this year, she'd never been interviewed. "Tell me what fear is," Tranel began. "Well, that's what I'm trying to -- to be honest, I truly have no clue," SM said, her voice raspy. That's actually a symptom of the condition that stole fear from her. Urbach-Wieth disease, which is characterized by a hoarse voice, small bumps around the eyes, and calcium deposits in the brain is rare in its own right -- only 400 people on the planet are known to have it -- but in SM's case, some of those brain-deposits happened to take over her amygdalae. These almond-shaped structures deep inside the brain are crucial to human fear response. And in SM's case, they've been totally calcified since she was a young woman. Now in her 40s, her fear-center is as good as gone. "It's a little bit as if you would go to this region and literally scoop it out," Antonio Damasio, another neuroscientist who studies SM, told "Invisibilia" hosts Lulu Miller and Alix Spiegel.
By Tia Ghose Being around strangers can cause people stress and, in turn, make them less able to feel others' pain, new research suggests. But giving people a drug that blocks the body's stress response can restore that sense of empathy, scientists said. What's more, the same effect shows up in both humans and mice. "In some sense, we've figured out what to do about increasing empathy as a practical matter," said Jeffrey Mogil, a neuroscientist at McGill University in Montreal. "We've figured out what stops it from happening and, therefore, the solution to make it happen more between strangers." Decreasing stress by doing a shared activity could be a simple way to increase empathy between people who don't know each other, the findings suggest. Past studies had found that mice seemed to feel the pain of familiar mice but were less responsive to foreign mice. Other studies found that, in both humans and mice, stress levels tended to rise around strangers. To see how stress and empathy are connected, Mogil and his colleagues placed two mice together in a cage, then inflicted a painful stimulus on one of them. When the mice were cage mates, the unaffected mouse showed more signs of pain than when they were strangers. But when the team gave the mice a drug called metyrapone, which blocks the formation of the stress hormone cortisol, the mice responded equally to the strangers' pain.
by Bethany Brookshire Drugs that treat anxiety can be real downers. While they may help you feel less anxious, drugs such as Valium and Xanax can leave you drowsy and unfocused. Long-term use of these compounds, a class of drugs called the benzodiazepines, can lead to dependence and tolerance. And patients often need higher and higher doses to calm their anxiety. Getting off the drugs requires careful weaning to avoid insomnia, tremors and other nasty withdrawal effects. But Subhashis Banerjee and colleagues at the Scripps Research Institute in Jupiter, Fla., have identified a potential new target for anti-anxiety drugs that avoids the drowsiness and other side effects that come with the standard treatments. The target is an integral part of the body’s internal clock, and in tests in mice, compounds aimed at it reduced measures of anxiety while keeping the mice awake. The possibilities show how basic science questions, such as how the body produces sleep and internal rhythms, could have clinical applications. But it’s important to remember that it’s a long way between mice and people. The proteins REV-ERB alpha and REV-ERB beta are found in cell nuclei throughout the body. These proteins are receptors that sense levels of heme, subsections of chemicals in the body containing iron atoms. Levels of heme rise and fall based on a cell’s activity. REV-ERB responds to these heme level changes by controlling the activation of genes within the cell’s nucleus that govern the cell’s 24-hour internal clock. This circadian rhythm plays an important role in controlling our sleep. © Society for Science & the Public 2000 - 2015.
Related chapters from BP7e: Chapter 15: Emotions, Aggression, and Stress; Chapter 14: Biological Rhythms, Sleep, and Dreaming
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress; Chapter 10: Biological Rhythms and Sleep
Link ID: 20489 - Posted: 01.15.2015
By Nicholas Weiler A friend can make even the shiest creature bold. Rats usually fear strange open spaces, but having a companion by their side makes the rodents more intrepid, scientists report in the current issue of Animal Cognition. Researchers tracked rats’ exploration of a large, unfamiliar room, first alone, then again 2 days later either alone or paired with a familiar cagemate. On their own, rats made short, hesitant forays into the open space before darting back to huddle by the door. Solitary rats’ anxiety in the room didn’t improve on their second visit. But adding a friend, even one who’d never seen the room before, gave the pair the confidence to actively explore, covering 50% more ground and running significantly faster than the control rats. And exploring with company seemed to boost the rats’ sense of security permanently. Placed in the room a third time, once more alone, the socialized rats boldly explored more new places than ever, while solo rats continued to cower. This illustrates that for communal animals like rats—and perhaps humans—friendship can be the best antidote to fear. © 2015 American Association for the Advancement of Scienc
By KEVIN RANDALL MILWAUKEE — When two financiers purchased the Milwaukee Bucks for $550 million last April, they promised to pour not only money and new management into the moribund franchise, but also the same kind of creative and critical thinking that had helped make them hedge fund billionaires. It was not enough to increase the franchise’s sales force or beef up the team’s analytics department — the Bucks were looking for a more elusive edge. So in May, the team hired Dan Hill, a facial coding expert who reads the faces of college prospects and N.B.A. players to determine if they have the right emotional attributes to help the Bucks. The approach may sound like palm reading to some, but the Bucks were so impressed with Hill’s work before the 2014 draft that they retained him to analyze their players and team chemistry throughout this season. With the tenets of “Moneyball” now employed in the front offices of every major sport, perhaps it was inevitable that professional teams would turn to emotion metrics and neuroscience tools to try to gain an edge in evaluating players. Many sports teams have adopted advanced data analytics to help determine a player’s athletic abilities and value. And now, some are taking it a step further — trying to analyze the psychological aspects of the players as well. “We spend quite a bit of time evaluating the players as basketball players and analytically,” said David Morway, Milwaukee’s assistant general manager, who works for the owners Wesley Edens and Marc Lasry. “But the difficult piece of the puzzle is the psychological side of it, and not only psychological, character and personality issues, but also team chemistry issues.” © 2014 The New York Times Company
Richard Stephens ‘The curve that sets everything straight” was how comedian Phyllis Diller once described the smile. And it’s true that there’s something charming, trustworthy and disarming about a smile – but this can be misleading. Dig a little deeper and you will understand a much less wholesome side. Because, ladies and gentleman, the smile is one of the biggest fakes going. I know what you’re thinking: we all pull a false smile now and again to appease our fellows and avoid unnecessary conflict. On the other hand, a genuine smile of true enjoyment is something different. Psychologists have named such a smile after the French neurologist Guillaume-Benjamin-Amand Duchenne de Boulogne. The Duchenne smile, utilising the muscles around the eyes that lift the cheeks to produce crow’s feet, has long been held as an inimitable sign of true human emotion. Or at least it was until 2013, when a team of researchers from Northeastern University, Boston, broke that hoodoo. Sarah Gunnery and her colleagues asked one group of volunteers to imitate smiles on photographs, and another group of volunteers to rate them. Some of the photographs depicted mouth-only smiles but others were Duchenne smiles, using mouth and eye muscles together. Surprisingly, a high proportion of individuals – two-thirds – could fake a Duchenne smile – and those that could do this were better able to put on false expressions in their everyday lives. This straightforward study indicates that even the sacrosanct Duchenne smile can be convincingly simulated. So much for smiling being an inimitable sign of true human emotion. So why are we so good at faking smiles? The answer isn’t necessarily sinister – some research shows you can actually smile yourself into a better mood. © 2014 Guardian News and Media Limited
by Helen Thomson HAVE you read this before? A 23-year-old man from the UK almost certainly feels like he has – he's the first person to report persistent déjà vu stemming from anxiety rather than any obvious neurological disorder. Nobody knows exactly how or why déjà vu happens, but for most of us it is rare. Some people experience it more often, as a side effect associated with epileptic seizures or dementia. Now, researchers have discovered the first person with what they call "psychogenic déjà vu" – where the cause appears to be psychological. The man's episodes began just after he started university, a period when he felt anxious and was also experiencing obsessive compulsions. As time went on, his déjà vu became more and more prolonged, and then fairly continuous after he tried LSD. Now, he avoids television and radio, and finds newspapers distressing as the content feels familiar. There are different theories as to what is going on, says Christine Wells at Sheffield Hallam University in the UK, who has written a paper on the man's experiences. "The general theory is that there's a misfiring of neurons in the temporal lobes – which deal with recollection and familiarity. That misfiring during the process of recollection means we interpret a moment in time as something that has already been experienced," she says. Surprisingly, when Wells gave the man a standard recall test, he scored more similarly to people of his own age without the condition than those with epilepsy-related déjà vu. An MRI and an EEG scan of his brain activity also showed no abnormalities. © Copyright Reed Business Information Ltd.
Related chapters from BP7e: Chapter 17: Learning and Memory; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 13: Memory, Learning, and Development; Chapter 11: Emotions, Aggression, and Stress
Link ID: 20427 - Posted: 12.18.2014
by Helen Thomson Scared of the dark? Terrified of heights? Spiders make you scream? For the first time, a person's lifelong phobia has been completely abolished overnight. Unfortunately, it required removing a tiny bit of the man's brain, so for now, most people will have to find another way to dispel their fears. The phobia was abolished by accident. A 44-year-old business man started having seizures out of the blue. Brain scans showed he had an abnormality in his left amygdala – an area in the temporal lobe involved in emotional reactions, among other things. Further tests showed the cause was sarcoidosis, a rare condition that causes damage to the lungs, skin and, occasionally, the brain. Doctors decided it was necessary to remove the man's damaged left amygdala. The surgery went well, but soon after the man noticed a strange turn of events. Not only did he have a peculiar "stomach-lurching" aversion to music – which was particularly noticeable when he heard the song accompanying a certain TV advert – but he also discovered he was no longer afraid of spiders. While his aversion to music waned over time, his arachnophobia never returned. Before the surgery he would throw tennis balls at spiders, or use hairspray to immobilise them before vacuuming them up. Now he is able to touch and observe the little critters at close distance and says he actually finds them fascinating. He hasn't noticed any changes to other kinds of fears or anxieties. For example, he is equally as anxious about public speaking now as he was prior to surgery. © Copyright Reed Business Information Ltd.
by Dan Jones The way your brain reacts to a single disgusting image can be used to predict whether you lean to the left or the right politically. A number of studies have probed the emotions of people along the political spectrum, and found that disgust in particular is tightly linked to political orientation. People who are highly sensitive to disgusting images – of bodily waste, gore or animal remains – are more likely to sit on the political right and show concern for what they see as bodily and spiritual purity, so tend to oppose abortion and gay marriage, for example. A team led by Read Montague, a neuroscientist at Virginia Tech in Roanoke, recruited 83 volunteers and performed fMRI brain scans on them as they looked at a series of 80 images that were either pleasant, disgusting, threatening or neutral. Participants then rated the images for their emotional impact and completed a series of questionnaires that assessed whether they were liberal, moderate or conservative. The brain-imaging results were then fed to a learning algorithm which compared the whole-brain responses of liberals and conservatives when looking at disgusting images versus neutral ones. For both political groups, the algorithm was able to pick out distinct patterns of brain activity triggered by the disgusting images. And even though liberals and conservatives consciously reported similar emotional reactions to the images, the specific brain regions involved and their patterns of activation differed consistently between the two groups – so much so that they represented a neural signature of political leaning, the team concludes. © Copyright Reed Business Information Ltd
By J. PEDER ZANE Striking it rich is the American dream, a magnetic myth that has drawn millions to this nation. And yet, a countervailing message has always percolated through the culture: Money can’t buy happiness. From Jay Gatsby and Charles Foster Kane to Tony Soprano and Walter White, the woefully wealthy are among the seminal figures of literature, film and television. A thriving industry of gossipy, star-studded magazines and websites combines these two ideas, extolling the lifestyles of the rich and famous while exposing the sadness of celebrity. All of which raises the question: Is the golden road paved with misery? Yes, in a lot of cases, according to a growing body of research exploring the connection between wealth and happiness. Studies in behavioral economics, cognitive psychology and neuroscience are providing new insights into how a changing American economy and the wiring of the human brain can make life on easy street feel like a slog. Make no mistake, it is better to be rich than poor — psychologically as well as materially. Levels of depression, anxiety and stress diminish as incomes rise. What has puzzled researchers is that the psychological benefits of wealth seem to stop accruing once people reach an income of about $75,000 a year. “The question is, What are the factors that dampen the rewards of income?” said Scott Schieman, a professor of sociology at the University of Toronto. “Why doesn’t earning even more money — beyond a certain level — make us feel even happier and more satisfied?” The main culprit, he said, is the growing demands of work. For millenniums, leisure was wealth’s bedfellow. The rich were different because they worked less. The tables began to turn in America during the 1960s, when inherited privilege gave way to educational credentials and advancement became more closely tied to merit. © 2014 The New York Times Company
James Hamblin People whose faces are perceived to look more "competent" are more likely to be CEOs of large, successful companies. Having a face that people deem "dominant" is a predictor of rank advancement in the military. People are more likely to invest money with people who look "trustworthy." These sorts of findings go on and on in recent studies that claim people can accurately guess a variety of personality traits and behavioral tendencies from portraits alone. The findings seem to elucidate either canny human intuition or absurd, misguided bias. There has been a recent boom in research on how people attribute social characteristics to others based on the appearance of faces—independent of cues about age, gender, race, or ethnicity. (At least, as independent as possible.) The results seem to offer some intriguing insight, claiming that people are generally pretty good at predicting who is, for example, trustworthy, competent, introverted or extroverted, based entirely on facial structure. There is strong agreement across studies as to what facial attributes mean what to people, as illustrated in renderings throughout this article. But it's, predictably, not at all so simple. Christopher Olivola, an assistant professor at Carnegie Mellon University, makes the case against face-ism today, in the journal Trends in Cognitive Sciences. In light of many recent articles touting people's judgmental abilities, Olivola and Princeton University's Friederike Funk and Alexander Todorov say that a careful look at the data really doesn't support these claims. And "instead of applauding our ability to make inferences about social characteristics from facial appearances," Olivola said, "the focus should be on the dangers."
Related chapters from BP7e: Chapter 15: Emotions, Aggression, and Stress; Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress; Chapter 14: Attention and Consciousness
Link ID: 20234 - Posted: 10.23.2014
by Mallory Locklear Do you have an annoying friend who loves bungee jumping or hang-gliding, and is always blathering on about how it never scares them? Rather than being a macho front, their bravado may have a biological basis. Research from Stony Brook University in New York shows that not all risk-takers are cut from the same cloth. Some actually seem to feel no fear – or at least their bodies and brains don't respond to danger in the usual way. The study is the first to attempt to tease apart the differences in the risk-taking population. In order to ensure every participant was a card-carrying risk-taker, the team led by Lilianne Mujica-Parodi, recruited 30 first-time skydivers. "Most studies on sensation-seeking compare people who take risks and people who don't. We were interested in something more subtle – those who take risks adaptively and those who do so maladaptively." In other words, do all risk-takers process potential danger in the same way or do some ignore the risks more than others? To find out, the researchers got their participants to complete several personality questionnaires, including one that asked them to rank how well statements such as, "The greater the risk the more fun the activity," described them. Next, the team used fMRI imaging to observe whether the participants' corticolimbic brain circuit – which is involved in risk assessment - was well-regulated. A well-regulated circuit is one that reacts to a threat and then returns to a normal state afterwards. © Copyright Reed Business Information Ltd
Helen Thomson You'll have heard of Pavlov's dogs, conditioned to expect food at the sound of a bell. You might not have heard that a scarier experiment – arguably one of psychology's most unethical – was once performed on a baby. In it, a 9-month-old, at first unfazed by the presence of animals, was conditioned to feel fear at the sight of a rat. The infant was presented with the animal as someone struck a metal pole with a hammer above his head. This was repeated until he cried at merely the sight of any furry object – animate or inanimate. The "Little Albert" experiment, performed in 1919 by John Watson of Johns Hopkins University Hospital in Baltimore, Maryland, was the first to show that a human could be classically conditioned. The fate of Albert B has intrigued researchers ever since. Hall Beck at the Appalachian State University in Boone, North Carolina, has been one of the most tenacious researchers on the case. Watson's papers stated that Albert B was the son of a wet nurse who worked at the hospital. Beck spent seven years exploring potential candidates and used facial analysis to conclude in 2009 that Little Albert was Douglas Merritte, son of hospital employee Arvilla. Douglas was born on the same day as Albert and several other points tallied with Watson's notes. Tragically, medical records showed that Douglas had severe neurological problems and died at an early age of hydrocephalus, or water on the brain. According to his records, this seems to have resulted in vision problems, so much so that at times he was considered blind. © Copyright Reed Business Information Ltd.
Related chapters from BP7e: Chapter 15: Emotions, Aggression, and Stress; Chapter 17: Learning and Memory
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress; Chapter 13: Memory, Learning, and Development
Link ID: 20156 - Posted: 10.04.2014
By Alyssa Abkowitz If you’re wary of investing in a certain stock or exchange-traded fund, it could be because of the your brain’s physical composition. In a recent study, 61 participants from the Northeastern U.S. were asked to choose between monetary options that differed in the level of risk. Questions included: “Would you prefer a 50 percent chance of receiving $5 or would you rather take a 13 percent chance of winning $50?” and “Would you prefer $10 for sure or a 50 percent chance of receiving $50?” Researchers found that individuals with more gray matter in a specific part of their brains tend to tolerate more financial risks, says Agnieszka Tymula, an economist at the University of Sydney and co-author of the findings. Most of the participants answered questions while their brains were being scanned, while others received MRIs afterward (the timing doesn’t make a difference because the researchers were looking at brain structure, not brain function). The study involved measuring the volume of gray matter, or the outer layer of the brain, in the right posterior parietal region of the cortex. Thicker gray matter corresponded to riskier responses. Tymula worked with researchers from Yale University, University College London, New York University, and the University of Pennsylvania. Their findings, published in the Journal of Neuroscience this month, dovetail with previous work in which Tymula found that adults become more risk-averse as they age. Other neuroscience research shows that people’s cortexes become thinner as they get older, meaning there could be a link between a thinning cortex and risk aversion. ©2014 Bloomberg L.P
Related chapters from BP7e: Chapter 15: Emotions, Aggression, and Stress; Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress; Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 20117 - Posted: 09.25.2014
by Bob Holmes THERE'S something primal in a mother's response to a crying infant. So primal, in fact, that mother deer will rush protectively to the distress calls of other infant mammals, such as fur seals, marmots and even humans. This suggests such calls might share common elements – and perhaps that these animals experience similar emotions. Researchers – and, indeed, all pet owners – know that humans respond emotionally to the distress cries of their domestic animals, and there is some evidence that dogs also respond to human cries. However, most people have assumed this is a by-product of domestication. However, Susan Lingle, a biologist at the University of Winnipeg, Canada, noticed that the infants of many mammal species have similar distress calls: simple sounds with few changes in pitch. She decided to test whether cross-species responses occur more widely across the evolutionary tree. So, Lingle and her colleague Tobias Riede, now at Midwestern University in Glendale, Arizona, recorded the calls made by infants from a variety of mammal species when separated from their mother or otherwise threatened. They then played the recordings through hidden speakers to wild mule deer (Odocoileus hemionus) out on the Canadian prairies. They found that deer mothers quickly moved towards the recordings of infant deer, but also towards those of infant fur seals, dogs, cats and humans, all of which call at roughly the same pitch. Even the ultrasonic calls of infant bats attracted the deer mothers if Lingle used software to lower their pitch to match that of deer calls. In contrast, they found the deer did not respond to non-infant calls such as birdsong or the bark of a coyote (American Naturalist, DOI: 10.1086/677677). © Copyright Reed Business Information Ltd.
Related chapters from BP7e: Chapter 15: Emotions, Aggression, and Stress; Chapter 9: Hearing, Vestibular Perception, Taste, and Smell
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress; Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 20095 - Posted: 09.19.2014
|By Daniel A. Yudkin If you’re reading this at a desk, do me a favor. Grab a pen or pencil and hold the end between your teeth so it doesn’t touch your lips. As you read on, stay that way—science suggests you’ll find this article more amusing if you do. Why? Notice that holding a pencil in this manner puts your face in the shape of a smile. And research in psychology says that the things we do—smiling at a joke, giving a gift to a friend, or even running from a bear—influence how we feel. This idea—that actions affect feelings—runs counter to how we generally think about our emotions. Ask average folks how emotions work—about the causal relationship between feelings and behavior—and they’ll say we smile because we’re happy, we run because we’re afraid. But work by such psychologists as Fritz Strack, Antonio Damasio, Joe LeDoux shows the truth is often the reverse: what we feel is actually the product, not the cause, of what we do. It’s called “somatic feedback.” Only after we act do we deduce, by seeing what we just did, how we feel. This bodes well, at first blush, for anyone trying to change their emotions for the better. All you’d need to do is act like the kind of person you want to be, and that’s who you’ll become. (Call it the Bobby McFerrin philosophy: “Aren’t happy? Don’t worry. Just smile!”) But new research, published in the Journal of Experimental Social Psychology by Aparna Labroo, Anirban Mukhopadhyay, and Ping Dong suggests there may be limits to our ability to proactively manage our own well-being. The team ran a series of studies examining whether more smiling led to more happiness. One asked people how much smiling they had done that day, and how happy they currently felt. Other studies manipulated the amount of smiling people actually did, either by showing them a series of funny pictures or by replicating a version of the pencil-holding experiment. As expected, across these experiments, the researchers found that the more people smiled, the happier they reported being. © 2014 Scientific American
By Smitha Mundasad Health reporter, BBC News Giving young people Botox treatment may restrict their emotional growth, experts warn. Writing in the Journal of Aesthetic Nursing, clinicians say there is a growing trend for under-25s to seek the wrinkle-smoothing injections. But the research suggests "frozen faces" could stop young people from learning how to express emotions fully. A leading body of UK plastic surgeons says injecting teenagers for cosmetic reasons is "morally wrong". Botox and other versions of the toxin work by temporarily paralysing muscles in the upper face to reduce wrinkling when people frown. Nurse practitioner Helen Collier, who carried out the research, says reality TV shows and celebrity culture are driving young people to idealise the "inexpressive frozen face." But she points to a well-known psychological theory, the facial feedback hypothesis, that suggests adolescents learn how best to relate to people by mimicking their facial expressions. She says: "As a human being our ability to demonstrate a wide range of emotions is very dependent on facial expressions. "Emotions such as empathy and sympathy help us to survive and grow into confident and communicative adults." But she warns that a "growing generation of blank-faced" young people could be harming their ability to correctly convey their feelings. "If you wipe those expressions out, this might stunt their emotional and social development," she says. The research calls for practitioners to use assessment tools to decide whether there are clear clinical reasons for Botox treatment. BBC © 2014
By Jonathan Webb Science reporter, BBC News Monkeys at the top and bottom of the social pecking order have physically different brains, research has found. A particular network of brain areas was bigger in dominant animals, while other regions were bigger in subordinates. The study suggests that primate brains, including ours, can be specialised for life at either end of the hierarchy. The differences might reflect inherited tendencies toward leading or following, or the brain adapting to an animal's role in life - or a little of both. Neuroscientists made the discovery, which appears in the journal Plos Biology, by comparing brain scans from 25 macaque monkeys that were already "on file" as part of ongoing research at the University of Oxford. "We were also looking at learning and memory and decision-making, and the changes that are going on in your brain when you're doing those things," explained Dr MaryAnn Noonan, the study's first author. The decision to look at the animals' social status produced an unexpectedly clear result, Dr Noonan said. "It was surprising. All our monkeys were of different ages and different genders - but with fMRI (functional magnetic resonance imaging) you can control for all of that. And we were consistently seeing these same networks coming out." BBC © 2014
Related chapters from BP7e: Chapter 15: Emotions, Aggression, and Stress; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress
Link ID: 20029 - Posted: 09.03.2014
Carl Zimmer An unassuming single-celled organism called Toxoplasma gondii is one of the most successful parasites on Earth, infecting an estimated 11 percent of Americans and perhaps half of all people worldwide. It’s just as prevalent in many other species of mammals and birds. In a recent study in Ohio, scientists found the parasite in three-quarters of the white-tailed deer they studied. One reason for Toxoplasma’s success is its ability to manipulate its hosts. The parasite can influence their behavior, so much so that hosts can put themselves at risk of death. Scientists first discovered this strange mind control in the 1990s, but it’s been hard to figure out how they manage it. Now a new study suggests that Toxoplasma can turn its host’s genes on and off — and it’s possible other parasites use this strategy, too. Toxoplasma manipulates its hosts to complete its life cycle. Although it can infect any mammal or bird, it can reproduce only inside of a cat. The parasites produce cysts that get passed out of the cat with its feces; once in the soil, the cysts infect new hosts. Toxoplasma returns to cats via their prey. But a host like a rat has evolved to avoid cats as much as possible, taking evasive action from the very moment it smells feline odor. Experiments on rats and mice have shown that Toxoplasma alters their response to cat smells. Many infected rodents lose their natural fear of the scent. Some even seem to be attracted to it. Manipulating the behavior of a host is a fairly common strategy among parasites, but it’s hard to fathom how they manage it. A rat’s response to cat odor, for example, emerges from complex networks of neurons that detect an odor, figure out its source and decide on the right response in a given moment. © 2014 The New York Times Company
By ANNA NORTH “You can learn a lot from what you see on a screen,” said Yalda T. Uhls. However, she told Op-Talk, “It’s not going to give you context. It’s not going to give you the big picture.” Ms. Uhls, a researcher at the Children’s Digital Media Center in Los Angeles, was part of a team that looked at what happened when kids were separated from their screens — phones, iPads, laptops and the like — for several days. Their findings may have implications for adults’ relationship to technology, too. For a paper published in the journal Computers in Human Behavior, the researchers studied 51 sixth-graders who attended a five-day camp where no electronic devices were allowed. Before and after the camp, they tested the kids’ emotion-recognition skills using photos of facial expressions and sound-free video clips designed to measure their reading of nonverbal cues. The kids did significantly better on both tests after five screen-free days; a group of sixth-graders from the same school who didn’t go to camp showed less or no improvement. Ms. Uhls, who also works for the nonprofit Common Sense Media, told Op-Talk that a number of factors might have been at play in the campers’ improvement. For instance, their time in nature might have played a role. But to her, the most likely explanation was the sheer increase in face-to-face interaction: “The issue really is not that staring at screens is going to make you bad at recognizing emotions,” she said. “It’s more that if you’re looking at screens you’re not looking at the world, and you’re not looking at people.” Many adults have sought out the same Internet-free experience the kids had, though they usually don’t go to camp to get it. The novelist Neil Gaiman took a “sabbatical from social media” in 2013, “so I can concentrate on my day job: making things up.” © 2014 The New York Times Company