Links for Keyword: Aggression

Follow us on Facebook and Twitter, or subscribe to our mailing list, to receive news updates. Learn more.


Links 1 - 20 of 291

Tina Hesman Saey COLD SPRING HARBOR, N.Y. — Taming animals makes an impression on their DNA. Domesticated animals tend to have genetic variants that affect similar biological processes, such as brain and facial development and fur coloration. Alex Cagan of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, reported the results May 6 at the Biology of Genomes conference. Cagan and colleagues examined DNA in Norway rats (Rattus norvegicus) that had been bred for 70 generations to be either tame or aggressive toward humans. Docility was associated with genetic changes in 1,880 genes in the rats. American minks (Neovison vison) bred for tameness over 15 generations had tameness-associated variants in 525 genes, including 82 that were also changed in the rats. The researchers also compared other domesticated animals, including dogs, cats, pigs and rabbits, with their wild counterparts. The domestic species and the minks had tameness-associated changes in genes for epidermal growth factor and associated proteins that stimulate growth of cells. Those proteins are important for the movement of neural crest cells within an embryo. That finding seems to support a recent hypothesis that changes in neural crest cells could be responsible for domestication syndrome, physical traits, including floppy ears, spotted coats and juvenile faces, which accompany tameness in many domestic animals. © Society for Science & the Public 2000 - 2015.

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: 20911 - Posted: 05.12.2015

By Emily Underwood A splashy headline appeared on the websites of many U.K. newspapers this morning, claiming that men whose brothers or fathers have been convicted of a sex offense are “five times more likely to commit sex crimes than the average male” and that this increased risk of committing rape or molesting a child “may run in a family’s male genes.” The study, published online today in the International Journal of Epidemiology, analyzed data from 21,566 male sex offenders convicted in Sweden between 1973 and 2009 and concluded that genetics may account for at least 40% of the likelihood of committing a sex crime. (Women, who commit less than 1% of Sweden’s sexual offenses, were omitted from the analysis.) The scientists have suggested that the new research could be used to help identify potential offenders and target high-risk families for early intervention efforts. But independent experts—and even the researchers who led the work, to a certain degree—warn that the study has some serious limitations. Here are a few reasons to take its conclusions, and the headlines, with a generous dash of salt. Alternate explanations: Most studies point to early life experiences, such as childhood abuse, as the most important risk factor for becoming a perpetrator of abuse in adulthood. The new study, however, did not include any detail about the convicted sex criminals’ early life exposure to abuse. Instead, by comparing fathers with sons, and full brothers and half-brothers reared together or apart, the scientists attempted to tease out the relative contributions of shared environment and shared genes to the risk of sexual offending. Based on their analyses, the researchers concluded that shared environment accounted for just 2% of the risk of sexual offense, while genetics accounted for roughly 40%. Although there is likely some genetic contribution to sexual offending—perhaps related to impulsivity or sex drive—the group “may be overestimating the role of genes” because their assumptions were inaccurate, says Fred Berlin, a psychiatrist and sexologist at Johns Hopkins University in Baltimore, Maryland. © 2015 American Association for the Advancement of Science.

Related chapters from BP7e: Chapter 15: Emotions, Aggression, and Stress; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress; Chapter 8: Hormones and Sex
Link ID: 20779 - Posted: 04.10.2015

By ERICA GOODE He was described, in the immediate aftermath of the Germanwings crash, as a cheerful and careful pilot, a young man who had dreamed of flying since boyhood. But in the days since, it has seemed increasingly clear that Andreas Lubitz, 27, the plane’s co-pilot, was something far more sinister: the perpetrator of one of the worst mass murder-suicides in history. If what researchers have learned about such crimes is any indication, this notoriety may have been just what Mr. Lubitz wanted. The actions now attributed to Mr. Lubitz — taking 149 unsuspecting people with him to a horrifying death — seem in some ways unfathomable, and his full motives may never be fully understood. But studies over the last decades have begun to piece together characteristics that many who carry out such violence seem to share, among them a towering narcissism, a strong sense of grievance and a desire for infamy. Adam Lankford, an associate professor of criminal justice at the University of Alabama, said that in his research on mass killers who also took their own lives, he has found “a significant number of cases where they mention a desire for fame, glory or attention as a motive.” Before Adam Lanza, 20, the Sandy Hook Elementary School shooter, killed 20 children, six adults and himself in 2012, he wrote in an online forum, “Just look at how many fans you can find for all different types of mass murderers.” Robert Hawkins, 19, who committed suicide after killing eight people at a shopping mall in Omaha in 2007, left a note saying “I’m gonna be famous,” punctuating the sentence with an expletive. And Dylan Klebold, 17, of Columbine High School fame, bragged that the goal was to cause “the most deaths in U.S. history…we’re hoping. We’re hoping.” “Directors will be fighting over this story,” Mr. Klebold said in a video made before the massacre. © 2015 The New York Times Company

Related chapters from BP7e: Chapter 16: Psychopathology: Biological Basis of Behavior Disorders; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 12: Psychopathology: Biological Basis of Behavioral Disorders; Chapter 11: Emotions, Aggression, and Stress
Link ID: 20766 - Posted: 04.07.2015

When it comes to fight or flight for brawling crickets, a chemical in the brain is in charge. Being roughed up in a skirmish can trigger nerve cells in Mediterranean field crickets (Gryllus bimaculatus) to release nitric oxide, making the losing cricket run away, scientists report online March 13 in Science Advances. Watch in this video as two crickets face off. When the loser hits its limit, it flees the fight. In a second bout, the loser then tries to avoid the winner. Nitric oxide prompts this continued submissive behavior, which lasts several hours before a cricket’s will to fight returns. “If you block nitric oxide they recover quickly, and if you give them nitric oxide they don’t,” says Paul Stevenson, a coauthor of the new research and behavioral neurobiologist at Leipzig University in Germany. “It’s a very simple algorithm for controlling a very complicated social situation.” P. Stevenson and J. Rillich. Adding up the odds—Nitric oxide signaling underlies the decision to flee and post-conflict depression of aggression. Science Advances. Published online March 13, 2015.doi: 10.1126/sciadv.1500060. © Society for Science & the Public 2000 - 2015.

Related chapters from BP7e: Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress
Link ID: 20686 - Posted: 03.14.2015

By TIMOTHY WILLIAMS In January 1972, Cecil Clayton was cutting wood at his family’s sawmill in southeastern Missouri when a piece of lumber flew off the circular saw blade and struck him in the forehead. The impact caved in part of Mr. Clayton’s skull, driving bone fragments into his brain. Doctors saved his life, but in doing so had to remove 20 percent of his frontal lobe, which psychiatrists say led Mr. Clayton to be tormented for years by violent impulses, schizophrenia and extreme paranoia. In 1996, his lawyers say, those impulses drove Mr. Clayton to kill a law enforcement officer. Today, as Mr. Clayton, 74, sits on death row, his lawyers have returned to that 1972 sawmill accident in a last-ditch effort to save his life, arguing that Missouri’s death penalty law prohibits the execution of severely brain-damaged people. Lawyers for Mr. Clayton, who has an I.Q. of 71, say he should be spared because his injury has made it impossible for him to grasp the significance of his death sentence, scheduled for March 17. “There was a profound change in him that he doesn’t understand, and neither did his family,” said Elizabeth Unger Carlyle, one of Mr. Clayton’s lawyers. While several rulings by the United States Supreme Court in recent years have narrowed the criteria for executing people who have a mental illness, states continue to hold wide sway in establishing who is mentally ill. The debate surrounding Mr. Clayton involves just how profoundly his impairment has affected his ability to understand what is happening to him. Mr. Clayton is missing about 7.7 percent of his brain. © 2015 The New York Times Company

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: 20669 - Posted: 03.09.2015

by Sandrine Ceurstemont Malte Andersson from the University of Gothenburg in Sweden has been testing whether Norwegian lemmings (Lemmus lemmus), like the one in the video above, deter predators by warning them of their aggressive nature with their shrieks. The vivid markings on the fur also indicate to predators that this critter isn't for eating. Having such warning colours – a phenomenon known as aposematism – is common in insects, snakes and frogs, but unusual in herbivorous mammals. This combination of hues made the lemmings easier to spot than their plain-looking neighbours, grey-sided voles. When a predator, played by humans in Andersson's test, is far away, these lemmings prefer to go unnoticed, he found. But when predators get closer, to within a few metres, these lemmings were much more likely to give out a warning call than their browner relatives. The conspicuous colours, aggressive calls and threatening postures together let predators know to expect a fight, and potentially damage, if they attempt to eat a Norwegian lemming. In contrast with the voles, these lemmings aggressively resist attacks by predatory birds. © Copyright Reed Business Information Ltd.

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: 20558 - Posted: 02.07.2015

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

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: 20531 - Posted: 01.29.2015

David Cox Bernd Heinrich was on a hike through the woods of New England when he observed something which would go on to change our perception of animal psychology. A group of ravens had gathered to feed on a dead moose. But rather than choosing to keep the bounty for themselves, they were making a strange call, one which seemed to be deliberately attracting more ravens to the feast. A biologist at the University of Vermont, Heinrich was initially confused. By helping their competitors, the ravens appeared to be defying all natural biological instinct. But as it transpired, their motivation was actually deeply selfish. The birds were juveniles who had discovered the moose in an adult raven’s territory. By inviting other ravens to join them, their intrusion was more likely to go unchallenged. Last month, an astonishing video emerged of a rhesus macaque successfully resuscitating another of its species which had been electrocuted at a train station in India. It is tempting to describe the sustained display of persistence and apparent concern as almost human. But there is a danger in viewing animal behaviour through the misty lens of human emotion. What both Heinrich’s “sharing ravens’ and the macaques of Kampur do provide is a window into the gradual evolution of one of the most human of traits – altruism. Altruism in its purest form should be an entirely selfless action. “If there’s any kind of selfish interest at stake, like secretly hoping for a return favour or even doing it deliberately because you know it will make you feel good, then that doesn’t really count at all,” says psychologist Michael Platt of the Center for Cognitive Neuroscience at Duke University, North Carolina.

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: 20522 - Posted: 01.27.2015

By ERICA GOODE A goat frolics with a baby rhinoceros. A pig nestles up to a house cat. A rat snake makes nice with the dwarf hamster originally intended as its lunch. Few things seem to capture the public imagination more reliably than friendly interactions between different species — a fact not lost on Anheuser-Busch, which during Sunday’s Super Bowl will offer a sequel to “Puppy Love,” its wildly popular 2014 Budweiser commercial about friendship between a Clydesdale and a yellow Labrador puppy. The earlier Super Bowl spot has drawn more than 55 million views on YouTube. Videos of unlikely animal pairs romping or snuggling have become so common that they are piquing the interest of some scientists, who say they invite more systematic study. Among other things, researchers say, the alliances could add to an understanding of how species communicate, what propels certain animals to connect across species lines and the degree to which some animals can adopt the behaviors of other species. “There’s no question that studying these relationships can give you some insight into the factors that go into normal relationships,” said Gordon Burghardt, a professor in the departments of psychology and ecology and evolutionary biology at the University of Tennessee, who added that one video he liked to show students was of a small and persistent tortoise tussling over a ball with a Jack Russell terrier. “Even one example raises the possibility that there’s something interesting going on here,” Dr. Burghardt said. Science has not entirely ignored unusual interactions between species. Biologists have described relationships formed to achieve a specific goal, like the cooperative hunting between groupers and moray eels. And in the mid-1900s, Konrad Lorenz and other ethologists demonstrated that during critical periods after birth, certain birds and other animals would follow the first moving object they saw, whether animal, human or machine, a phenomenon known as imprinting. Dr. Lorenz was famously photographed with a gaggle of “imprinted” geese trailing behind him. © 2015 The New York Times Company

Related chapters from BP7e: Chapter 15: Emotions, Aggression, and Stress; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress; Chapter 13: Memory, Learning, and Development
Link ID: 20521 - Posted: 01.27.2015

By Susan Chenelle and Audrey Fisch “Lord of the Flies” has been a classroom staple for decades, perhaps because the issues of bullying and male aggression remain central concerns in the lives of adolescents, even if they aren’t stranded on a desert island. “To Study Aggression, a Fight Club for Flies” zeros in on the issue of male aggression, but in fruit flies, rather than humans. The connections, beyond the titular, are tantalizing. James Gorman, the science reporter, is focused on research about the neuropeptide tachykinin, produced in the brains of male fruit flies only. When researchers manipulated the neurons, they could decrease aggression in the flies. What does this suggest about the neuroscience of aggression? And what is the relationship between aggression and gender? Below, we match Mr. Gorman’s article with a passage from Chapter 8 of “Lord of the Flies” in which Jack leads his peers in the hunt of a sow. At this point in the novel, Jack has overthrown Ralph and Piggy’s attempts to establish order and civility among the boys. Jack has won over a majority of the boys, and in this scene the group engages in a collective hunt for food that transforms itself into a kind of orgy of male violence. The gender politics of the scene are striking: The attack on the mother pig calls out for careful analysis. The boys are, for example, “wedded to her in lust” and climactically “heavy and fulfilled upon her” at the moment of her killing. What point is William Golding trying to make, here and elsewhere in the novel, about the nature of these young men and the ways in which they turn to and relish in aggression and violence? Key Question: What is the relationship between aggression and gender? © 2015 The New York Times Company

Related chapters from BP7e: Chapter 15: Emotions, Aggression, and Stress; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress; Chapter 8: Hormones and Sex
Link ID: 20511 - Posted: 01.23.2015

By Susan Milius Whole scientific careers have gone into understanding why a harmless handful of fluff like a California ground squirrel taunts rattlesnakes. Now Rulon Clark and his team at San Diego State University are exploring the puzzle of why the squirrels also seem to taunt rocks, sticks and the occasional shrub. On spotting a snake, a California ground squirrel (Otospermophilus beecheyi) stares and sniffs, or if the snake is uncoiled, may even kick sand at it. And in bursts, the squirrel flags its tail left and right “like a windshield wiper,” Clark says. A rattler can strike a target 30 centimeters away in less than 70 milliseconds. But ground squirrels twist and dodge fast enough to have a decent chance of escape. Also, adult squirrels from snake country have evolved some resistance to venom. So taunting is worth the risks as a signal to neighboring squirrels and to the snake that its ambush attempt has been discovered. After getting publicly and lengthily squirreled, snakes often just slip away. Yet the squirrels also nyah-nyah tail flag at places where snakes might be but aren’t. To see if flagging indicates wariness, Clark and his colleagues built a squirrel startler that shoots out a cork using the classic spring that launches gag snakes out of cans (see video below). At spots with no sign of real snakes, squirrels mostly nibbled seeds in apparent tranquility with only a rare tail flag. The pop of a cork typically sent these squirrels scampering off on four speed-blurred paws. © Society for Science & the Public 2000 - 2014.

Related chapters from BP7e: Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress
Link ID: 20453 - Posted: 01.06.2015

By John Bohannon If you had the choice between hurting yourself or someone else in exchange for money, how altruistic do you think you’d be? In one infamous experiment, people were quite willing to deliver painful shocks to anonymous victims when asked by a scientist. But a new study that forced people into the dilemma of choosing between pain and profit finds that participants cared more about other people’s well-being than their own. It is hailed as the first hard evidence of altruism for the young field of behavioral economics. Human behavior toward others is hard to predict. On the one hand, we stand out in the animal world for our altruism, often making significant sacrifices to help out a stranger in need. And all but the most antisocial people experience psychological distress at witnessing, let alone causing, pain in others. Yet study after study in the field of behavioral economics has demonstrated that we tend to value our own needs and desires above those of others. For example, researchers have found that just thinking about money makes people behave more selfishly. To try to reconcile the angels and devils of our nature, a team led by Molly Crockett, a psychologist at the University of Oxford in the United Kingdom, combined the classic psychological and economics tools for probing altruism: pain and money. Everyone has their own pain threshold, so the first task was a pain calibration. Researchers administered electric shocks with electrodes attached to the wrists of 160 subjects, starting at an almost imperceptible level and amping up until the subject described the pain as intolerable. (For most people, that threshold for pain is similar to holding your wrist under a stream of 50°C water.) © 2014 American Association for the Advancement of Science.

Related chapters from BP7e: Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress
Link ID: 20320 - Posted: 11.18.2014

By Melissa Hogenboom Science reporter, BBC News A genetic analysis of almost 900 offenders in Finland has revealed two genes associated with violent crime. Those with the genes were 13 times more likely to have a history of repeated violent behaviour. The authors of the study, published in the journal Molecular Psychiatry, said at least 4-10% of all violent crime in Finland could be attributed to individuals with these genotypes. But they stressed the genes could not be used to screen criminals. Many more genes may be involved in violent behaviour and environmental factors are also known to have a fundamental role. Even if an individual has a "high-risk combination" of these genes the majority will never commit a crime, the lead author of the work Jari Tiihonen of the Karolinska Institutet in Sweden said. "Committing a severe, violent crime is extremely rare in the general population. So even though the relative risk would be increased, the absolute risk is very low," he told the BBC. The study, which involved analysis of almost 900 criminals, is the first to have looked at the genetic make-up of so many violent criminals in this way. Warrior gene Each criminal was given a profile based on their offences, categorising them into violent or non-violent. The association between genes and previous behaviour was strongest for the 78 who fitted the "extremely violent offender" profile. This group had committed a total of 1,154 murders, manslaughters, attempted homicides or batteries. A replication group of 114 criminals had all committed at least one murder. BBC © 2014

Related chapters from BP7e: Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress
Link ID: 20252 - Posted: 10.28.2014

By Linda Carroll The debate over whether violent movies contribute to real-world mayhem may have just developed a wrinkle: New research suggests they might enhance aggression only in those already prone to it. Using PET scanners to peer into the brains of volunteers watching especially bloody movie scenes, researchers determined that the way a viewer’s brain circuitry responds to violent video depends upon whether the individual is aggressive by nature. The study was published Wednesday in PLOS One. “Just as beauty is in the eye of the beholder, environmental stimuli are in the brain of the beholder,” said Nelly Alia-Klein, the study’s lead author and an associate professor at the Friedman Brain Institute and the Icahn School of Medicine at Mount Sinai Hospital in New York City. To test the importance of personality, Alia-Klein and her colleagues rounded up 54 healthy men, some of whom had a history of getting into physical fights, while the others had no history of aggression. The researchers scanned the volunteers three times: doing nothing, watching emotionally charged video and viewing a violent movie. “It wasn’t the whole [violent] movie,” Alia-Klein said, “just the violent scenes, one after another after another.” Along with the brain scans, the researchers monitored blood pressure and asked about the viewers’ moods every 15 minutes.

Related chapters from BP7e: Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress
Link ID: 20132 - Posted: 09.30.2014

By JAMES GORMAN Are chimpanzees naturally violent to one another, or has the intrusion of humans into their environment made them aggressive? A study published Wednesday in Nature is setting off a new round of debate on the issue. The study’s authors argue that a review of all known cases of when chimpanzees or bonobos in Africa killed members of their own species shows that violence is a natural part of chimpanzee behavior and not a result of actions by humans that push chimpanzee aggression to lethal attacks. The researchers say their analysis supports the idea that warlike violence in chimpanzees is a natural behavior that evolved because it could provide more resources or territory to the killers, at little risk. But critics say the data shows no such thing, largely because the measures of human impact on chimpanzees are inadequate. While the study is about chimpanzees, it is also the latest salvo in a long argument about the nature of violence in people. In studying chimpanzee violence, “we’re trying to make inferences about human evolution,” said Michael L. Wilson, an anthropologist at the University of Minnesota and a study organizer. There is no disagreement about whether chimpanzees kill one another, or about some of the claims that Dr. Wilson and his 29 co-authors make. The argument is about why chimpanzees kill. Dr. Wilson and the other authors, who contributed data on killings from groups at their study sites, say the evidence shows no connection between human impact on the chimpanzee sites and the number of killings. He said the Ngogo group of chimpanzees in Uganda “turned out to be the most violent group of chimpanzees there is,” even though the site was little disturbed by humans. They have a pristine habitat, he said, and “they go around and kill their neighbors.” © 2014 The New York Times Company

Related chapters from BP7e: Chapter 15: Emotions, Aggression, and Stress; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress; Chapter 8: Hormones and Sex
Link ID: 20094 - Posted: 09.19.2014

By John Horgan On this blog, in my book The End of War and elsewhere (see Further Reading and Viewing), I have knocked the deep roots theory of war, which holds that war stems from an instinct deeply embedded in the genes of our male ancestors. Inter-community killings are rare among chimpanzees and non-existent among bonobos, according to a new report in Nature, undercutting the theory that the roots of war extend back to the common ancestor of humans and chimps. Proponents of this theory—notably primatologist Richard Wrangham—claim it is supported by observations of inter-community killings by chimpanzees, Pan troglodytes, our closest genetic relatives. Skeptics, including anthropologists Robert Sussman and Brian Ferguson, have pointed out that chimpanzee violence might be not an adaptation but a response to environmental circumstances, such as human encroachment. This “human impacts” hypothesis is rejected in a new report in Nature by a coalition of 30 primatologists, including Wrangham and lead author Michael Wilson. In “Lethal aggression in Pan is better explained by adaptive strategies than human impacts,” Wilson et al. analyze 152 killings in 18 chimpanzee communities and find “little correlation with human impacts.” Given that the primary interest in chimp violence is its alleged support of the deep-roots theory, it might seem odd, at first, that Wilson et al. do not mention human warfare. Actually, this omission is wise, because the Nature report undermines the deep-roots theory of war, and establishes that the “human impact” issue is a red herring. © 2014 Scientific American,

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: 20092 - Posted: 09.18.2014

by Bethany Brookshire When a laboratory mouse and a house mouse come nose to nose for the first time, each one is encountering something it has never seen before. They are both Mus musculus. But the wild mouse is facing a larger, fatter, calmer and less aggressive version of itself that’s the result of brother-to-sister inbreeding for generations, resulting in mice that are almost completely genetically identical. Laboratory mice are incredibly valuable tools for research into diseases from Alzheimer’s to Zellweger syndrome. Scientists have a deep understanding of lab mouse DNA, and can use that knowledge to study how specific genes may control certain behaviors and underlie disease. But with all the inbreeding comes some traits that, while desirable in a lab mouse, may not reflect the behavior of an animal in the wild. So for some questions, and some behaviors, scientists might need something a bit wilder. A new study takes lab mice back to their roots and along the way uncovers a new gene function. Lea Chalfin and colleagues at the Weizmann Institute of Science in Rohovot, Israel, bred laboratory mice with wild mice for 10 generations. The result was a mouse with wild mouse genes and wild mouse behavior — with a few important lab mouse genes mixed in. The technique allows scientists to place specific mutations in a wild mouse. The results have interesting implications for studying the mouse species, and might provide some new ways to study human disease as well. Chalfin and her colleagues were especially interested in behaviors linked to female aggression. © Society for Science & the Public 2000 - 2013

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: 19980 - Posted: 08.20.2014

By NATALIE ANGIER SOUTH LUANGWA NATIONAL PARK, ZAMBIA — We saw the impala first, a young buck with a proud set of ridged and twisted horns, like helical rebar, bounding across the open plain at full, desperate gallop. But why? A moment later somebody in our vehicle gasped, and the answer became clear. Rising up behind the antelope, as though conjured on movie cue from the aubergine glow of the late afternoon, were six African wild dogs, running in single file. They moved with military grace and precision, their steps synchronized, their radio-dish ears cocked forward, their long, puppet-stick legs barely skimming the ground. Still, the impala had such a jump on them that the dogs couldn’t possibly catch up — could they? We gunned the engine and followed. The pace quickened. The dogs’ discipline held steady. They were closing the gap and oh, no, did I really want to watch the kill? To my embarrassed relief, the violence was taken off-screen, when prey and predators suddenly dashed up a hill and into obscuring bushes. By the time we reached the site, the dogs were well into their communal feast, their dark muzzles glazed with bright red blood, their white-tipped tails wagging in furious joy. “They are the most enthusiastic animals,” said Rosie Woodroffe of the Institute of Zoology in London, who has studied wild dogs for the last 20 years. “Other predators may be bigger and fiercer, but I would argue that there is nothing so enthusiastic as a wild dog,” she said. “They live the life domestic dogs wish they could live.” In 1997, while devising an action plan to help save the wild dog species, Lycaon pictus, Dr. Woodroffe felt anything but exuberant. Wild dogs were considered among the most endangered of Africa’s mammals; Dr. Woodroffe had yet to see one in the wild, and she feared she never would. © 2014 The New York Times Company

Related chapters from BP7e: Chapter 15: Emotions, Aggression, and Stress; Chapter 19: Language and Hemispheric Asymmetry
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress; Chapter 15: Language and Our Divided Brain
Link ID: 19941 - Posted: 08.12.2014

From David Beckham’s infamous kick at France '98 to Luis Suárez chomping Giorgio Chiellini's shoulder in Brazil last week, the history of the World Cup is littered with moments of impulsive aggression that appear to defy all rational explanation. The story of human impulsivity stretches back deep into our evolutionary past. By nature, we are all prone to making quick, rash decisions that may lead to regret, and in some cases a four-month ban from international football. Impulsivity is actually a survival mechanism and was essential in the African savanna where our species evolved around a million and a half years ago. For our ancestors, the ability to make split-second decisions could make the difference between life and death. All of us have deep primal instincts but over the several hundred million years of evolution separating our reptilian ancestors from the first mammals, and eventually primates, the cognitive ability to exercise self-restraint has increased. While most living things make this decision purely as a trade-off between risk and reward, only humans can decide to exercise self-restraint on the basis of how they think they will be perceived by others – an ability that emerged some time in the past 100,000 years or so. “We evolved to be very social animals, living in large groups, and so we have developed inhibitory mechanisms in the more recently evolved parts of the prefrontal cortex,” explains Michael Price of the School of Social Sciences at the University of Brunel. “This is the social centre of the brain. Our big reason not to be impulsive is because of your reputation and how other people are going to judge you and perhaps ostracise you as we saw with Beckham in the aftermath of France ’98.” © 2014 Guardian News and Media Limited

Related chapters from BP7e: Chapter 15: Emotions, Aggression, and Stress; Chapter 19: Language and Hemispheric Asymmetry
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress; Chapter 15: Language and Our Divided Brain
Link ID: 19784 - Posted: 07.03.2014

By Jonathan Webb Science reporter, BBC News A new theory suggests that our male ancestors evolved beefy facial features as a defence against fist fights. The bones most commonly broken in human punch-ups also gained the most strength in early "hominin" evolution. They are also the bones that show most divergence between males and females. The paper, in the journal Biological Reviews, argues that the reinforcements evolved amid fighting over females and resources, suggesting that violence drove key evolutionary changes. For many years, this extra strength was seen as an adaptation to a tough diet including nuts, seeds and grasses. But more recent findings, examining the wear pattern and carbon isotopes in australopith teeth, have cast some doubt on this "feeding hypothesis". "In fact, [the australopith] boisei, the 'nutcracker man', was probably eating fruit," said Prof David Carrier, the new theory's lead author and an evolutionary biologist at the University of Utah. Masculine armour Instead of diet, Prof Carrier and his co-author, physician Dr Michael Morgan, propose that violent competition demanded the development of these facial fortifications: what they call the "protective buttressing hypothesis". In support of their proposal, Carrier and Morgan offer data from modern humans fighting. Several studies from hospital emergency wards, including one from the Bristol Royal Infirmary, show that faces are particularly vulnerable to violent injuries. 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: 19710 - Posted: 06.09.2014