Chapter 15. Emotions, Aggression, and Stress
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By Michael Price When you’re smiling, it may feel like the whole world is smiling with you, but a new study suggests that some facial expressions may not be so universal. In fact, several expressions commonly understood in the West—including one for fear—have very different meanings to one indigenous, isolated society in Papua New Guinea. The new findings call into question some widely held tenets of emotional theory, and they may undercut emerging technologies, like robots and artificial intelligence programs tasked with reading people’s emotions. For more than a century, scientists have wondered whether all humans experience the same basic range of emotions—and if they do, whether they express them in the same way. In the 1870s, it was the central question Charles Darwin explored in The Expression of the Emotions in Man and Animals. By the 1960s, emeritus psychologist Paul Ekman, then at the University of California (UC) in San Francisco, had come up with an accepted methodology to explore this question. He showed pictures of Westerners with different facial expressions to people living in isolated cultures, including in Papua New Guinea, and then asked them what emotion was being conveyed. Ekman’s early experiments appeared conclusive. From anger to happiness to sadness to surprise, facial expressions seemed to be universally understood around the world, a biologically innate response to emotion. That conclusion went virtually unchallenged for 50 years, and it still features prominently in many psychology and anthropology textbooks, says James Russell, a psychologist at Boston College and corresponding author of the recent study. But over the last few decades, scientists have begun questioning the methodologies and assumptions of the earlier studies. © 2016 American Association for the Advancement of Science.
Link ID: 22761 - Posted: 10.18.2016
By Virginia Morell Human-produced noise in the ocean is likely harming marine mammals in numerous unknown ways, according to a comprehensive new report from the National Academies of Sciences, Engineering, and Medicine. That’s because there are insufficient data to determine how the ill effects of noise created by ships, sonar signals, and other activities interact with other threats, including pollution, climate change, and the loss of prey due to fishing. The report, which was sponsored by several government agencies and released on 7 October, provides a new framework for researchers to begin exploring these cumulative impacts. “There’s a growing recognition that interactions between stressors on marine mammals can’t right now be accurately assessed," said Peter Tyack, a marine mammal biologist at the University of St Andrews in the United Kingdom, in a webinar on the report. Tyack also chaired the committee that prepared the study, "Approaches to Understanding the Cumulative Effects of Stressors on Marine Mammals." Killer whales, for instance, are known to swim away from areas where they have encountered sonar signals of about 142 decibels, a sound level lower than currently allowed by the U.S. Navy for its ships, Tyack said, referring to a 2014 study in The Journal of the Acoustical Society of America that determined the mammals’ likely response. But scientists don’t yet know how other marine mammals might respond. They also don’t know whether or how other factors, such as encountering an oil spill or colliding with a ship, would—or would not—compound the cetaceans’ response to these sounds; or how or whether such combined stressors matter to the animals’ long-term health and overall population. © 2016 American Association for the Advancement of Science.
Alison Abbott Arrival in a foreign, hostile country causes many refugees great stress. On an ice-cold day in January, clinical psychologist Emily Holmes picked up a stack of empty diaries and went down to Stockholm’s central train station in search of refugees. She didn’t have to look hard. Crowds of lost-looking young people were milling around the concourse, in clothes too flimsy for the freezing air. “It struck me hard to see how thin some of the young men were,” she says. Holmes, who works at Stockholm’s Karolinska Institute, was seeking help with her research — a pilot project on post-traumatic stress disorder (PTSD), which is all too common in refugees. She wanted to see whether they would be willing to spend a week noting down any flashbacks — fragmented memories of a trauma that rush unbidden into the mind and torment those with PTSD. She easily found volunteers. And when they returned the diaries, Holmes was shocked to see that they reported an average of two a day — many more than the PTSD sufferers she routinely dealt with. “My heart went out to them,” she says. “They managed to travel thousands of kilometres to find their way to safety with this level of symptoms.” Europe is experiencing the largest movement of people since the Second World War. Last year, more than 1.2 million people applied for asylum in the European Union — and those numbers underestimate the scale of the problem. Germany, which has taken in the lion’s share of people, reckons that it received more than a million refugees in 2015, tens of thousands of whom have yet to officially apply for asylum. Most came from Syria, Afghanistan and Iraq. Many have experienced war, shock, upheaval and terrible journeys, and they often have poor physical health. The crisis has attracted global attention and sparked political tension as countries struggle to accommodate and integrate the influx. © 2016 Macmillan Publishers Limited
Annette Heist Nisha Pradhan is worried. The recent college graduate just turned 21 and plans to live on her own. But she's afraid she won't be able to stay safe. That's because Pradhan is anosmic — she isn't able to smell. She can't tell if milk is sour, or if she's burning something on the stove, or if there's a gas leak, and that worries her. "It actually didn't even strike me as being a big deal until I got to college," Pradhan says. Back home in Pennington, N.J., her family did her smelling for her, she says. She's moved in with them for now, but she's looking for a place of her own. "Now that I'm searching for ways or places to live as an independent person, I find more and more that the sense of smell is crucial to how we live our lives," Pradhan says. There's no good estimate for how many people live with smell loss. Congenital anosmia, being born without a sense of smell, is a rare condition. Acquired smell loss is more common. That loss can be total, or what's known as hyposmia, a diminished sense of smell. Pradhan doesn't know how she lost her sense of smell. She thinks she was born with it because as a child, she says she liked to eat and ate a lot. But there came a point where she lost interest in food. "That's actually one of the first things that people notice whenever they have a smell problem, is food doesn't taste right anymore," says Beverly Cowart, a researcher at the Monell Chemical Senses Center in Philadelphia. That's because eating and smell go hand in hand. How food tastes often relies on what we smell. © 2016 npr
By Andy Coghlan More men inevitably means more testosterone-fuelled violence, right? Wrong, according to a comprehensive analysis exploring how a surplus of men or women affect crime rates across the US. In areas where men outnumber women, there were lower rates of murders and assaults as well as fewer sex-related crimes, such as rapes, sex offences and prostitution. Conversely, higher rates of these crimes occurred in areas where there were more women than men. Ryan Schacht of the University of Utah in Salt Lake City and his colleagues analysed sex ratio data from all 3082 US counties, provided by the US Census Bureau in 2010. They compared this with crime data for the same year, issued by the US Federal Bureau of Investigation. They only included information about women and men of reproductive age. For all five types of offence analysed, rising proportions of men in a county correlated with fewer crimes– even when accounting for other potential contributing factors such as poverty. The results suggest that current policies aimed at defusing violence and crime by reducing the amount of men in male-dominated areas may backfire. According to Schacht, when women are in short supply, men must be more dutiful to win and retain a partner. With an abundance of women, men are spoilt for choice and adopt more promiscuous behaviour that brings them into conflict with other men, and more likely to commit sex-related offences. © Copyright Reed Business Information Ltd.
By Emily Underwood When you let forth a big, embarrassing yawn during a boring lecture or concert, you succumb to a reflex so universal among animals that Charles Darwin mentioned it in his field notes. “Seeing a dog & horse & man yawn, makes me feel how much all animals are built on one structure,” he wrote in 1838. Scientists, however, still don’t agree on why we yawn or where it came from. So in a new study, researchers watched YouTube videos of 29 different yawning mammals, including mice, kittens, foxes, hedgehogs, walruses, elephants, and humans. (Here is a particularly cute montage used in the study.) They discovered a pattern: Small-brained animals with fewer neurons in the wrinkly outer layer of the brain, called the cortex, had shorter yawns than large-brained animals with more cortical neurons, the scientists report today in Biology Letters. Primates tended to yawn longer than nonprimates, and humans, with about 12,000 million cortical neurons, had the longest average yawn, lasting a little more than 6 seconds. African elephants, whose brains are close to the same weight as humans’ and have a similar number of cortical neurons, lasted about 6 seconds. The yawns of tiny-brained mice, in contrast, were less than 1.5 seconds in duration. The study lends support to a long-held hypothesis that yawning has an important physiological effect, such as increasing blood flood to the brain and cooling it down, the scientists say. © 2016 American Association for the Advancement of Science.
By GINA KOLATA It is not easy to be fat in America, even though more than a third of adults are obese. Donald J. Trump brought the issue of fat shaming to the fore during and after last week’s debate, when he disparaged a former Miss Universe winner who gained weight and when he said the hacking of the Democratic National Committee’s emails might have been done by “somebody sitting on their bed that weighs 400 pounds.” But there also is a body of evidence showing that the effects of fat shaming and stigmatizing go far beyond such remarks, beyond the stares fat people get on the street, the cutting comments strangers make about their weight and the “funny” greeting cards featuring overweight people. It turns out that fat prejudice differs from other forms in ways that make it especially difficult to overcome. The problems with fat shaming start early. Rebecca Puhl, the deputy director of the University of Connecticut’s Rudd Center for Food Policy and Obesity, and her colleagues find that weight is the most common reason children are bullied in school. In one study, nearly 85 percent of adolescents reported seeing overweight classmates teased in gym class. Dr. Puhl and her colleagues asked fat kids who was doing the bullying. It turned out that it was not just friends and classmates but also teachers and — for more than a third of the bullied — parents. “If these kids are not safe at school or at home, where are they going to be supported?” Dr. Puhl asked. The bullying problem is not limited to the United States. Dr. Puhl and her colleagues found the same situation in Canada, Australia and Iceland. Women face harsher judgment than men, Dr. Puhl reports. The cutting remarks can begin when a woman’s body mass index is in the overweight range, while for men the shaming tends to start when they are obese. And women who are obese report more than three times as much shaming and discrimination as men of equal obesity. © 2016 The New York Times Company
Emily Underwood To human observers, bumblebees sipping nectar from flowers appear cheerful. It turns out that the insects may actually enjoy their work. A new study suggests that bees experience a “happy” buzz after receiving a sugary snack, although it’s probably not the same joy that humans experience chomping on a candy bar. Scientists can’t ask bees or other animals how they feel. Instead, researchers must look for signs of positive or negative emotions in an animal’s decision making or behavior, says Clint Perry, a neuroethologist at Queen Mary University of London. In one such study, for example, scientists shook bees vigorously in a machine for 60 seconds — hard enough to annoy, but not hard enough to cause injury — and found that stressed bees made more pessimistic decisions while foraging for food. The new study, published in the Sept. 30 Science, is the first to look for signs of positive bias in bee decision making, Perry says. His team trained 35 bees to navigate a small arena connected to a plastic tunnel. When the tunnel was marked with a blue flower, the bees learned that a tasty vial of sugar water awaited them at its end. When a green flower was present, there was no reward. Once the bees learned the difference, the scientists threw the bees a curveball: Rather than being blue or green, the flower had a confusing blue-green hue. Faced with the ambiguous blossom, the bees appeared to dither, meandering around for roughly 100 seconds before deciding whether to enter the tunnel. Some didn’t enter at all. But when the scientists gave half the bees a treat — a drop of concentrated sugar water — that group spent just 50 seconds circling the entrance before deciding to check it out. Overall, the two groups flew roughly the same distances at the same speeds, suggesting that the group that had gotten a treat first had not simply experienced a boost in energy from the sugar, but were in a more positive, optimistic state, Perry says. |© Society for Science & the Public 2000 - 2016.
Rebecca Hersher A new study of violent behavior in more than 1,000 mammal species found the meerkat is the mammal most likely to be murdered by one of its own kind. The study, led by José María Gómez of the University of Grenada in Spain and published Wednesday in the journal Nature, analyzed more than 4 million deaths among 1,024 mammal species and compared them with findings in 600 studies of violence among humans from ancient times until today. The findings tell us two things: Some amount of violence between humans is attributable to our place on the evolutionary tree. Meerkats are surprisingly murderous. To be clear, the study's authors did not set out to prove (or disprove) a theory of meerkat violence; they were investigating what mammalian data might tell us about humans. But Ed Yong at The Atlantic organized the study's exhaustive list of mammals to make this helpful chart ranking animals by their murderousness. Some of the animals with reputations for docility are actually more dangerous to each other than creatures known for their aggression. Chinchillas kill each other more often than brown bears turn on their own kind. New Zealand sea lions are more murderous than actual lions. And, as you can see, about 20 percent of meerkat deaths are murders. Their violence has been documented; a 2006 study described in National Geographic documented meerkat mothers killing the offspring of other females to maintain dominance. © 2016 npr
Link ID: 22707 - Posted: 09.29.2016
By Karl Gruber Five lionesses in Botswana have grown a mane and are showing male-like behaviours. One is even roaring and mounting other females. Male lions are distinguished by their mane, which they use to attract females, and they roar to protect their territory or call upon members of their pride. Females lack a mane and are not as vocal. . New Scientist Live: Book tickets to our festival of ideas and discovery – 22 to 25 September in London But sometimes lionesses grow a mane and even behave a bit like males. However, until now, reports of such maned lionesses have been extremely rare and largely anecdotal. We knew they existed, but little about how they behave. Now, Geoffrey D. Gilfillan at the University of Sussex in Falmer, UK, and colleagues have reported five lionesses sporting a mane at the Moremi Game Reserve in Botswana’s Okavango delta. Gilfillan started studying these lionesses back in March 2014, and for the next two years he focused on recording the behaviour of one of them, called SaF05. She had an underdeveloped mane and was larger than most females. “While SaF05 is mostly female in her behaviour – staying with the pride, mating males – she also has some male behaviours, such as increased scent-marking and roaring, as well as mounting other females,” says Gilfillan. © Copyright Reed Business Information Ltd.
Nicola Davis Tyrannosaur, Breaking the Waves and Schindler’s List might make you reach for the tissues, but psychologists say they have found a reason why traumatic films are so appealing. Researchers at Oxford University say that watching traumatic films boosts feelings of group bonding, as well as increasing pain tolerance by upping levels of feel-good, pain-killing chemicals produced in the brain. “The argument here is that actually, maybe the emotional wringing you get from tragedy triggers the endorphin system,” said Robin Dunbar, a co-author of the study and professor of evolutionary psychology at the University of Oxford. Previous research has found that laughing together, dancing together and working in a team can increase social bonding and heighten pain tolerance through an endorphin boost. “All of those things, including singing and dancing and jogging and laughter, all produce an endorphin kick for the same reason - they are putting the musculature of the body under stress,” said Dunbar. Being harrowed, he adds, could have a similar effect. “It has turned out that the same areas in the brain that deal with physical pain also handle psychological pain,” said Dunbar. Writing in the journal Royal Society Open Science, Dunbar and colleagues describe how they set out to unpick whether our love of storytelling, a device used to share knowledge and cultivate a sense of identity within a group, is underpinned by an endorphin-related bonding mechanism. © 2016 Guardian News and Media Limited
Richard J. McNally The welcoming letter to the class of 2020 in which Jay Ellison, a dean at the University of Chicago, told incoming students not to expect trigger warnings on campus struck a nerve in a highly polarized debate that is embroiling academia. Trigger warnings are countertherapeutic because they encourage avoidance of reminders of trauma, and avoidance maintains P.T.S.D. Trigger warnings, critics claim, imperil academic freedom and further infantilize a cohort of young people accustomed to coddling by their helicopter parents. Proponents of trigger warnings point out that many students have suffered trauma, exemplified by alarming rates of sexual assault on campus. Accordingly, they urge professors to warn students about potentially upsetting course materials and to exempt distressed students from classes covering topics likely to trigger post-traumatic stress disorder, or P.T.S.D., symptoms, such as flashbacks, nightmares and intrusive thoughts about one’s personal trauma. Proponents of trigger warnings are deeply concerned about the emotional well-being of students, especially those with trauma histories. Yet lost in the debate are two key points: Trauma is common, but P.T.S.D. is rare. Epidemiological studies show that many people are exposed to trauma in their lives, and most have had transient stress symptoms. But only a minority fails to recover, thereby developing P.T.S.D. Students with P.T.S.D. are those most likely to have adverse emotional reactions to curricular material, not those with trauma histories whose acute stress responses have dissipated. However, trigger warnings are countertherapeutic because they encourage avoidance of reminders of trauma, and avoidance maintains P.T.S.D. Severe emotional reactions triggered by course material are a signal that students need to prioritize their mental health and obtain evidence-based, cognitive-behavioral therapies that will help them overcome P.T.S.D. These therapies involve gradual, systematic exposure to traumatic memories until their capacity to trigger distress diminishes. © 2015 The New York Times Company
By Jessica Hamzelou After experiencing post-traumatic stress disorder after being raped, Karestan Koenen made it her career to study the condition. Now at Harvard University, Koenen is leading the largest ever genetic study of PTSD, by sifting through the genomes of tens of thousands of people (see Why women are more at risk of PTSD – and how to prevent it”). She tells New Scientist how her experiences shaped her career What was your idea of PTSD before you experienced it yourself? I would have associated it with men who served in the military – the stereotype of a Vietnam veteran who has experienced really horrible combat, and comes back and has nightmares about it. Do you think that is how PTSD is perceived by the public generally? Yes. People know that PTSD is related to trauma, and that people can have flashbacks and nightmares. But they tend to think it is associated with combat. A lot of popular images of PTSD come from war movies, and people tend to associate being a soldier with being a man. They are less aware that most PTSD is related to things that happen to civilians – things like rape, sexual assault and violence, which can affect women more than men. Is this misperception of PTSD problematic? It’s a problem in the sense that women or men who have PTSD from non-combat experiences might not recognise what they have as PTSD, and because of that, may not end up getting help. And if you saw it in a loved one, you may not understand what was going on with them. © Copyright Reed Business Information Ltd.
By NATALIE ANGIER The female bonobo apes of the Wamba forest in the Democratic Republic of Congo had just finished breakfast and were preparing for a brief nap in the treetops, bending and crisscrossing leafy branches into comfortable day beds. But one of the females was in estrus, her rump exceptionally pink and swollen, and four males in the group were too excited to sleep. They took turns wildly swinging and jumping around the fertile female and her bunkmates, shaking the branches, appearing to display their erections and perforating the air with high-pitched screams and hoots. Suddenly, three older, high-ranking female bonobos bolted up from below, a furious blur of black fur and swinging limbs and, together with the female in estrus, flew straight for the offending males. The males scattered. The females pursued them. Tree boughs bounced and cracked. Screams on all sides grew deafening. Three of the males escaped, but the females cornered and grabbed the fourth one — the resident alpha male. He was healthy, muscular and about 18 pounds heavier than any of his captors. But no matter. The females bit into him as he howled and struggled to pull free. Finally, “he dropped from the tree and ran away, and he didn’t appear again for about three weeks,” said Nahoko Tokuyama, of the Primate Research Institute at Kyoto University in Japan, who witnessed the encounter. When the male returned, he kept to himself. Dr. Tokuyama noticed that the tip of one of his toes was gone. “Being hated by females,” she said in an email interview, “is a big matter for male bonobos.” The toe-trimming incident was extreme but not unique. Describing results from their long-term field work in the September issue of Animal Behaviour, Dr. Tokuyama and her colleague Takeshi Furuichi reported that the female bonobos of Wamba often banded together to fend off male aggression, and in patterns that defied the standard primate rule book. © 2016 The New York Times Company
By Daniel Engber In the spring of 2013, a 63-year-old social psychologist in Wurzburg, Germany, made a bold suggestion in a private email chain. For months, several dozen of his colleagues had been squabbling over how to double-check the scientific literature on “social priming,” the idea that even very subtle cues—the height of a chair, the temperature of a cup of coffee, the color of a printed word—can influence someone’s behavior or judgment. Now the skeptics in the group wanted volunteers: Who among the priming experts and believers would help them with a large-scale replication effort, in which a major finding would be tested in many different labs at once? Who—if anyone—would agree to put his research to this daunting test? The experts were reluctant to step forward. In recent months their field had fallen into scandal and uncertainty: An influential scholar had been outed as a fraud; certain bedrock studies—even so-called “instant classics”—had seemed to shrivel under scrutiny. But the rigidity of the replication process felt a bit like bullying. After all, their work on social priming was delicate by definition: It relied on lab manipulations that had been precisely calibrated to elicit tiny changes in behavior. Even slight adjustments to their setups, or small mistakes made by those with less experience, could set the data all askew. So let’s say another lab—or several other labs—tried and failed to copy their experiments. What would that really prove? Would it lead anyone to change their minds about the science?
Link ID: 22609 - Posted: 08.29.2016
James Hamblin Like The Atlantic? Subscribe to the Daily, our free weekday email newsletter. Elite tennis players have an uncanny ability to clear their heads after making errors. They constantly move on and start fresh for the next point. They can’t afford to dwell on mistakes. Peter Strick is not a professional tennis player. He’s a distinguished professor and chair of the department of neurobiology at the University of Pittsburgh Brain Institute. He’s the sort of person to dwell on mistakes, however small. “My kids would tell me, dad, you ought to take up pilates. Do some yoga,” he said. “But I’d say, as far as I’m concerned, there's no scientific evidence that this is going to help me.” Still, the meticulous skeptic espoused more of a tennis approach to dealing with stressful situations: Just teach yourself to move on. Of course there is evidence that ties practicing yoga to good health, but not the sort that convinced Strick. Studies show correlations between the two, but he needed a physiological mechanism to explain the relationship. Vague conjecture that yoga “decreases stress” wasn’t sufficient. How? Simply by distracting the mind? The stress response in humans is facilitated by the adrenal glands, which sit on top of our kidneys and spit adrenaline into our blood whenever we’re in need of fight or flight. That stress response is crucial in dire circumstances. But little of modern life truly requires it (especially among academic scientists). Most of the time, our stress responses are operating as a sort of background hum, keeping us on edge. Turn that off, and we relax. © 2016 by The Atlantic Monthly Group
Link ID: 22599 - Posted: 08.25.2016
Are you a giver or a taker? Brain scans have identified a region of the cerebral cortex responsible for generosity – and some of us are kinder than others. The area was identified using a computer game that linked different symbols to cash prizes that either went to the player, or one of the study’s other participants. The volunteers readily learned to score prizes that helped other people, but they tended to learn how to benefit themselves more quickly. Read more: The kindness paradox: Why be generous? MRI scanning revealed that one particular brain area – the subgenual anterior cingulate cortex – seemed to be active when participants chose to be generous, prioritising benefits for someone else over getting rewards for themselves. But Patricia Lockwood, at the University of Oxford, and her team found that this brain area was not equally active in every volunteer. People who rated themselves as having higher levels of empathy learned to benefit others faster, and these people had more activity in this particular brain area, says Lockwood. This finding may lead to new ways to identify and understand anti-social and psychopathic behavior. Journal reference: PNAS, DOI: 10.1073/pnas.1603198113 © Copyright Reed Business Information Ltd.
In a global study of myasthenia gravis, an autoimmune disease that causes muscle weakness and fatigue, researchers found that surgical removal of an organ called the thymus reduced patients’ weakness, and their need for immunosuppressive drugs. The study, published in the New England Journal of Medicine, was partially funded by the National Institutes of Health. “Our results support the idea that thymectomy is a valid treatment option for a major form of myasthenia gravis,” said Gil Wolfe, M.D., Professor and Irvin and Rosemary Smith Chair of Neurology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, New York, and a leader of the study. The Thymectomy Trial in Non-Thymomatous Myasthenia Gravis Patients Receiving Prednisone (MGTX) was a randomized, controlled study conducted on 126 patients aged 18-65 between 2006 and 2012. The researchers compared the combination of surgery and immunosuppression with the drug prednisone with prednisone treatment alone. They performed extended transternal thymectomies on 57 patients. This major surgical procedure aims to remove most of the thymus, which requires opening of a patient’s chest. On average the researchers found that the combination of surgery and prednisone treatment reduced overall muscle weakness more than prednisone treatment alone. After 36 months of prednisone treatment, both groups of patients had better QMG scores, a measure of muscle strength. Scores for the patients who had thymectomies and prednisone were 2.84 points better than patients who were on prednisone alone.
By Effy Redman “There is no one who has not smiled at least once,” writes Marianne LaFrance, a Yale University psychology professor, in her 2011 book “Lip Service: Smiles in Life, Death, Trust, Lies, Work, Memory, Sex and Politics.” Her book explores how smiling unifies us. Like breath, the smile is universal. We smile to connect, to forgive, to love. A smile is beauty, human. But I have never smiled. Not once. I was born with Moebius syndrome — a rare form of facial paralysis that results from damage in the womb to the sixth and seventh cranial nerves, which control the muscles of the face. I was born in Britain, on the same day in 1982 the country’s first test-tube twins were born. But while science has created medical miracles like test-tube babies, there’s little that doctors can do for someone with Moebius syndrome. Decades later, I still cannot smile. Or frown. Or do any of the infinite subtle and not-so-subtle things with my face that I see others in the world around me doing every day. Doctors describe people with Moebius as having a “mask-like expression.” And that is what strangers must see. A frozen face, eyes unblinking. My mouth always open, motionless, the left corner of my lips slightly lower than the right. Walking down the street, I can feel the touch of casual observers’ eyes. A child’s very first “social smile” usually occurs six to eight weeks after birth, eagerly awaited by new parents. Because, as an infant, my face remained so expressionless, when I began laughing it took my mother a while to realize that the sound I was making was laughter. At what point, I wonder, did I begin to compensate for the absence of my smile. © 2016 The New York Times Company
Link ID: 22542 - Posted: 08.11.2016
By TATIANA SCHLOSSBERG Need a laugh? Get online and take a look at videos of baby Japanese macaques smiling as they sleep. Their faces twitch, usually just on one side and for less than a second. A lip curls, a nose wrinkles — as if they were hairy, wry elves. Newborn Japanese macaques -- like humans and chimpanzees -- were found to make facial expressions called "spontaneous smiles." Watch the full video. Credit Kyoto University Primate Research Institute Maybe you don’t laugh, maybe you just smile back — O.K., fine. But you may owe that smile to the human version of this infant’s facial spasm. Some scientists suspect spontaneous smiles in these monkeys echo the development of our own expressions. Scientists from the Primate Research Institute at Kyoto University in Japan have observed these spontaneous smiles in Japanese macaques for the first time, according to a new study published in the journal Primates. Spontaneous smiles have previously been observed in infant humans and chimpanzees, but this is the first time they have been seen in another primate species. The scientists watched seven macaque monkeys for an average of 44 minutes, during which the monkeys happened to fall asleep. During REM sleep, each of the monkeys spontaneously smiled at least once, for a little less than a second on average. All told, the seven monkeys smiled 58 times, mostly on the left side of their faces. Human and macaque infants alike primarily smile on one side of their faces. But after two months, human babies begin to smile bilaterally. Around the same time, they also begin to offer up “social smiles,” indicating to others a feeling of happiness. According to the study, scientists think that the earliest spontaneous smiles are key to the development of the zygomaticus major muscle, which is responsible for moving your lips up or to the side, allowing you to smile, among other things. Spontaneous smiles in these monkeys echo the development of our own expressions. Watch the full video.