Links for Keyword: Aggression

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by Sara Reardon If you want to know whether your new fluffy puppy will be a cuddly friend or snarl at and bite anything that moves, you might want to check out the length of its genes. Researchers at the University of Tokyo in Japan asked 100 Akita owners to fill out questionnaires about whether their pooches were naughty or nice. When they looked at the doggies' DNA, the scientists found that the meanest males more often had a shortened gene for a receptor that responds to various male hormones. The gene variant produces a form of the protein that has previously been shown to respond more strongly to testosterone. This is the first time that canine aggression has been associated with genetic differences in the male hormone receptor, the researchers report in Biology Letters this week. Over half of the Akitas they studied had this variant. Yet mean female dogs weren't more likely to have the short variant than the gentle dogs, suggesting that females respond differently to these hormones. © 2010 American Association for the Advancement of Science.

Related chapters from BP7e: Chapter 15: Emotions, Aggression, and Stress; Chapter 5: Hormones and the Brain
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress; Chapter 8: Hormones and Sex
Link ID: 15156 - Posted: 03.31.2011

by Shanta Barley Female hamadryas baboons may be vulnerable to a form of domestic violence from which they feel unable to escape – even if they have the opportunity. Most large papionin monkeys – a group including macaques, baboons and mandrills – rely on wandering males to disperse genes through the population. But studies suggest that gene flow through populations of hamadryas baboons (Papio hamadryas) in north-east Africa is mainly through females – even though males keep tight control of them and punish wanderers through vicious biting. In 1968, biologist Hans Kummer suggested that females move when they are abducted by another male – but only now have biologists observed such abductions. Mathew Pines at the Filoha Hamadryas Project in Addis Ababa, Ethiopia, witnessed three abductions between 2007 and 2009. Each time, the original male embarked on an often bloody rescue mission to locate and retrieve the female. Larissa Swedell at the City University of New York, Pines's co-author on the new study, speculates that abduction is not considered a "fair" way to gain a new female, and so the loss isn't accepted by the original male. The rescue missions were helped by the females, who willingly returned to the rescuer despite a history of violent treatment by that male. "The bond is so strong that a female will run to her male when she is frightened, even if he is the source of the threat," says Swedell. © Copyright Reed Business Information Ltd.

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: 15130 - Posted: 03.24.2011

By Clara Moskowitz The latest neuroscience research is presenting intriguing evidence that the brains of certain kinds of criminals are different from those of the rest of the population. While these findings could improve our understanding of criminal behavior, they also raise moral quandaries about whether and how society should use this knowledge to combat crime. In one recent study, scientists examined 21 people with antisocial personality disorder – a condition that characterizes many convicted criminals. Those with the disorder "typically have no regard for right and wrong. They may often violate the law and the rights of others," according to the Mayo Clinic. Brain scans of the antisocial people, compared with a control group of individuals without any mental disorders, showed on average an 18 percent reduction in the volume of the brain's middle frontal gyrus, and a 9 percent reduction in the volume of the orbital frontal gyrus — two sections in the brain's frontal lobe. Another brain study, published in the September 2009 Archives of General Psyciatry, compared 27 psychopaths — people with severe antisocial personality disorder — to 32 non-psycopaths. In the psychopaths, the researchers observed deformations in another part of the brain called the amygdala, with the psychopaths showing a thinning of the outer layer of that region called the cortex and, on average, an 18-percent volume reduction in this part of brain. © 2011 LiveScience.com.

Related chapters from BP7e: Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress
Link ID: 15068 - Posted: 03.05.2011

By Bruce Bower WASHINGTON — When an unrelenting penchant for misbehaving joins forces with lack of emotion, guilt and empathy, 7-year-olds are headed for years of severe conduct problems, a long-term study of English youngsters suggests. Youngsters who regularly misbehave and get into trouble at age 7, and who also display so-called callous-unemotional traits, frequently stay on a troubled course until at least age 12, according to a new investigation described February 20 in Washington, D.C., at the annual meeting of the American Association for the Advancenent of Science. “I’m not suggesting that these children are psychopaths, but callous-unemotional traits can be used to identify kids at risk of persistent, severe antisocial behavior,” said psychologist Nathalie Fontaine of Indiana University in Bloomington, who directed the study. Adult psychopaths similarly show no remorse for crimes and blunted emotional reactions, although they often possess considerable empathy that they use to prey on others. These findings indicate that callous-unemotional traits should be factored into the definition of a particularly virulent form of childhood conduct disorder in the next manual of psychiatric disorders, Fontaine said. Chronic misbehavior alone defines conduct disorder in the current fourth edition of the psychiatric manual used by doctors to define mental ailments, now being revised. © Society for Science & the Public 2000 - 2011

Related chapters from BP7e: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 13: Memory, Learning, and Development; Chapter 11: Emotions, Aggression, and Stress
Link ID: 15027 - Posted: 02.21.2011

Ewen Callaway Sex and violence are intertwined in mice. A tiny patch of cells buried deep within a male's brain determines whether it fights or mates, and there is good reason to believe humans possess a similar circuit. The study, published in Nature today1, shows that when these neurons are quieted, mice ignore intruding males they would otherwise attack. Yet when the cells are activated, mice assault inanimate objects, and even females they ought to court. The cells lie within an area of the hypothalamus with known links to violent behaviour. An electrical jolt to this vicinity causes cats and rats to turn violent, but neurophysiological experiments conducted decades ago stimulated too big an area to identify the specific brain circuits, let alone the individual neurons, involved in aggression. More recently, scientists studying mice engineered to lack specific genes have found that some of them act more aggressively than normal mice. "We really don't know which part of the brain went wrong in those mice. Consequently it's tough to make sense of that behaviour," says Dayu Lin, a neuroscientist now at New York University and an author of the study, who began searching for the seat of aggression in mice while working with David Anderson at the California Institute of Technology in Pasadena. © 2011 Nature Publishing Group,

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: 14994 - Posted: 02.12.2011

Jessica Marshall Mild-mannered male squid turn into furious fighting machines when their tentacles brush a chemical on the surface of squid eggs, a finding that could give insights into how aggression works. The discovery also reveals how male squid compete for female mating partners. "I think that this is really a novel and kind of wonderful addition to our understanding of how aggression might work," said Russell Fernald of Stanford University, who was not a part of the study. Researchers diving on squid spawning grounds had noticed that not just female squid would hang around the many mop-like clusters of egg capsules. "We noticed underwater that the males were attracted to the eggs, too. This made no sense. All the eggs are fertilized already. This caught our attention," lead author Roger Hanlon of the Marine Biological Laboratory in Woods Hole, Mass. told Discovery News. A key to solving the puzzle came during a Cape Cod dive. "There was absolutely nothing that was happening, it was Deadsville." Hanlon said. So, he fetched some squid eggs from the boat and brought them back to the dive site. "I just put the squid eggs on the bottom. Within a minute or two, one bold male squid went down and touched them. He came back up to the squid above him and started fighting with other squid." © 2011 Discovery Communications, LLC.

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: 14991 - Posted: 02.12.2011

By Laura Sanders A cluster of nerve cells have founded their own tiny fight club. These cells, nestled deep in a primitive part of the brain, compel mice to aggressively maul not just intruder males, but also females and blown-up rubber gloves, a study finds. What’s more, the fight cells have an intertwined and thorny relationship with nearby “mate” cells, a discovery that may shed light on human sexual violence. “This is absolutely awesome,” says neuroscientist Newton Canteras of the University of São Paulo, who was not involved in the study. “They [researchers] were able to pinpoint one tiny region in the hypothalamus that is responsible for the aggressive response.” The research, led by Dayu Lin of New York University’s Langone Medical Center, was published in the Feb. 10 Nature. Earlier studies had pointed to the hypothalamus, an almond-sized structure important for hunger, thirst and body temperature, as an aggression center in the brain. Electrical stimulation there made cats and rats attack targets. But researchers didn’t have a clear idea of where in the hypothalamus the fight neurons reside. Now, for the first time, scientists have pinpointed the exact location, says study coauthor David Anderson, a Howard Hughes Medical Institute investigator at Caltech. Researchers found the cells by monitoring the brains of male mice during attacks on male mouse intruders. If the hypothalamus is a country, “these cells are located in one neighborhood in a city in a state in that country,” he says. © Society for Science & the Public 2000 - 2011

Related chapters from BP7e: Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress
Link ID: 14974 - Posted: 02.10.2011

By SINDYA N. BHANOO For some genes, either the father’s version or the mother’s version is active, but not both. Which version of the gene works is determined before conception, as the sperm and egg are developing, in a process called imprinting. By mimicking that process in the lab, and turning off a gene in mice, scientists have produced a change in social dominance behavior. In laboratory tests, mice with the paternal version of the gene known as Grb10 inactivated were more aggressive in their behavior, according to new research in the journal Nature. The researchers had two methods of measuring social dominance. They found that mice with the inactive gene engaged in more social grooming, and nibbled off more fur and whiskers of other mice. Also, when two mice were placed in a tube and approached each other, mice with the inactive gene were less likely to back down and turn away. “Both males and females with the paternal gene off are adopting this socially dominant behavior,” said Andrew Ward, a geneticist with the Center for Regenerative Medicine at the University of Bath in Britain. In natural reproduction, the paternal version of the gene is generally active, Dr. Ward said, but some mice may have a greater number of active versions than others. “We’ve shown the extreme,” he said. “But you might have a more subtle variation in how much this behavior is expressed.” © 2011 The New York Times Company

Related chapters from BP7e: Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress
Link ID: 14931 - Posted: 01.29.2011

by Greg Miller Testimony on the brain activity of a convicted murderer may have saved him from the death penalty. Earlier this month, a jury in Miami rejected the death penalty and chose life in prison for Grady Nelson, who in 2005 stabbed his wife 61 times, killing her, and stabbed and raped her 11-year-old, mentally handicapped daughter. A report in The Miami Herald last weekend suggests that measurements of Nelson's brain activity may have influenced some members of the jury, who viewed the results as evidence of a brain injury that would partially explain his behavior. But some scientists are critical of the way this technology was used in the case. During the sentencing phase of the trial, the court heard testimony from Robert Thatcher, a neuroscientist and president of by Applied Neuroscience Inc. of St. Petersburg, Florida. Thatcher's company examined Nelson using a method called quantitative electroencephalography (QEEG). As in standard EEG, technicians place electrodes on the skull to record electrical activity in the brain. In QEEG, a computer program analyzes these recordings to locate regions of abnormal activity. In Nelson's case, there was an obvious abnormality in the left frontal lobe, Thatcher says. Thatcher also testified that Nelson exhibited "sharp waves" originating from this region. These large spikes in the EEG trace are typically seen in people with epilepsy. Grady is not epileptic, but he does have a history of at least three traumatic brain injuries, Thatcher said yesterday in an interview. © 2010 American Association for the Advancement of Science.

Related chapters from BP7e: Chapter 15: Emotions, Aggression, and Stress; Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress; Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
Link ID: 14789 - Posted: 12.16.2010

by Virginia Morell As any dog owner knows, dogs pay close attention to each other's growls—and with good reason. A new study reveals that dogs can tell another canine's size simply by listening to its growl. The size information is so accurate that a dog hearing a growl can match the sound to a photograph of the growler—a complex cognitive talent previously seen only in primates. In a previous study, Péter Pongrácz, an ethologist at Eötvös Loránd University in Hungary, and colleagues showed that dogs use a specific growl ("this bone is mine") when guarding a tasty bone. The growl always causes a listening dog to stop in its tracks. In their new study, the scientists tested the responses of dogs seated next to their owners, so that the animals felt comfortable in the lab. Twenty-four of the 96 dogs were shown images of two dogs projected onto a screen in front of them (see picture). One image showed a small dog less than 52 centimeters tall; the other image was of the same dog but projected as being taller than 60 cm (a 30% increase in size). The other dogs were shown control images, either of large and small triangles or of the silhouettes of large and small cats. The researchers then played recorded food-guarding growls—from either a large or a small dog—on a speaker placed between the two projected images. The scientists filmed the dogs, recording where the canines looked as they listened to the growls. © 2010 American Association for the Advancement of Science.

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: 14788 - Posted: 12.16.2010

by Debora MacKenzie It's been called the "warrior gene" – a mutation that seems to make people more aggressive. Now researchers report that people with this gene may not be aggressive, just better at spotting their own interests. Previous research has found that people with MAOA-L, a gene that controls signalling chemicals in the brain, can be more aggressive. But there is enormous controversy about this, as the gene's effects seem to vary with people's backgrounds. Cary Frydman and colleagues at the California Institute of Technology in Pasadena have now found that people with MAOA-L "just make better choices", says Frydman. "This isn't the same as aggression." Variants of the gene MAOA produce less or more of an enzyme that degrades several signalling chemicals, known as neurotransmitters. People with MAOA-L, which results in less of the enzyme, sometimes show more aggression or impulsivity – but not always. To try to dissect these differences, Frydman gave 83 male volunteers 140 hypothetical choices. With 3 minutes for each choice, the men had to decide whether they preferred a sure thing, say being given $2, or a risky option, for example a 50:50 chance of gaining $10 or losing $5. © Copyright Reed Business Information Ltd.

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: 14755 - Posted: 12.09.2010

By Emily Anthes In the wake of several tragedies that have made bullying a high-profile issue, it’s becoming clear that harassment by one’s peers is something more than just a rite of passage. Bullied kids are more likely to be depressed, anxious, and suicidal. They struggle in school — when they decide to show up at all. They are more likely to carry weapons, get in fights, and use drugs. But when it comes to the actual harm bullying does, the picture grows murkier. The psychological torment that victims feel is real. But perhaps because many of us have experienced this sort of schoolyard cruelty and lived to tell the tale, peer harassment is still commonly written off as a “soft” form of abuse — one that leaves no obvious injuries and that most victims simply get over. It’s easy to imagine that, painful as bullying can be, all it hurts is our feelings. A new wave of research into bullying’s effects, however, is now suggesting something more than that — that in fact, bullying can leave an indelible imprint on a teen’s brain at a time when it is still growing and developing. Being ostracized by one’s peers, it seems, can throw adolescent hormones even further out of whack, lead to reduced connectivity in the brain, and even sabotage the growth of new neurons. These neurological scars, it turns out, closely resemble those borne by children who are physically and sexually abused in early childhood. Neuroscientists now know that the human brain continues to grow and change long after the first few years of life. By revealing the internal physiological damage that bullying can do, researchers are recasting it not as merely an unfortunate rite of passage but as a serious form of childhood trauma. © 2010 NY Times Co.

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: 14739 - Posted: 12.04.2010

By Susan Milius Not to reopen any emotional scars from Thanksgiving dinner, but an unusual study of an animal social network suggests that ending up as the butt of unfriendly interactions could be in part inherited. The study, in yellow-bellied marmots, gives the first look beyond people at what facets of social relationships might have genetic components, says coauthor Daniel Blumstein of UCLA. It’s receiving incoming social attention, particularly in grouchy interactions, that showed a small but intriguing genetic influence, Blumstein says. Aspects of initiating interactions in a network, whether to dish out snubs or snuggles, showed no evidence of heritability, according to the paper posted online November 29 in the Proceedings of the National Academy of Sciences. “I am completely blown away by this paper,” says James Fowler, professor of medical genetics and political science at the University of California, San Diego. In human networks, he and his colleagues have found the marmotlike pattern of heritability in aspects of received social ties but not in initiated ones. Fowler had suspected that the asymmetry in people came from a quirk of limiting the number of friends in the study. Marmots didn’t have that limitation though, he says, “so the idea that there may be something systematic here between species is extremely interesting.” Marmots don’t have Facebook yet, but animals living among clusters of burrows in Colorado do interact enough for observers to plot networks with each marmot as a node. An exchange might be friendly, such as a marmot grooming a neighbor or settling down tranquilly nearby. Or a social interaction might go sour, with one marmot nipping or chasing another. © Society for Science & the Public 2000 - 2010

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: 14716 - Posted: 11.30.2010

By SINDYA N. BHANOO The human tendency to form close bonds with people other than kin may have primal roots. Researchers from Germany report in the journal Current Biology that male macaques exhibit a social bonding behavior similar to human friendship. A macaque in Thailand. Scientists say males of the species develop bonds like human friendship. Macaque monkeys live in groups of 50 to 60, but “every male in the group has a few other males he interacts with more than others,” said Oliver Schülke, the study’s lead author and an evolutionary biologist at the University of Göttingen. Dr. Schülke and his colleagues studied male Assamese macaques in Thailand over a period of five years and monitored their behavior. Macaques that spent a lot of time within 1.5 meters of each other were considered friends, since it is easy to attack another macaque at this distance. Males that groomed each other’s bodies frequently and for excessive periods of time were also considered friends. Often, they groomed areas that an individual could groom himself. “The grooming seems to work to foster these bonds,” Dr. Schülke said. “The hygiene aspect was only one part of it.” The bonds can lead to the forming of coalitions, where a group of males might fight another male to improve rank and social status, the researchers found. Copyright 2010 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: 14703 - Posted: 11.23.2010

WHAT makes people psychopaths is not an idle question. Prisons are packed with them. So, according to some, are boardrooms. The combination of a propensity for impulsive risk-taking with a lack of guilt and shame (the two main characteristics of psychopathy) may lead, according to circumstances, to a criminal career or a business one. That has provoked a debate about whether the phenomenon is an aberration, or whether natural selection favours it, at least when it is rare in a population. The boardroom, after all, is a desirable place to be—and before the invention of prisons, even crime might often have paid. To shed some light on this question Elsa Ermer and Kent Kiehl of the University of New Mexico, Albuquerque, decided to probe psychopaths’ moral sensibilities and their attitude to risk a little further. Their results do not prove that psychopathy is adaptive, but they do suggest that it depends on specific mechanisms (or, rather, a specific lack of them). Such specificity is often the result of evolution. Past work has established that psychopaths have normal levels of intelligence (they are only rarely Hannibal Lecter-like geniuses). Nor does their lack of guilt and shame seem to spring from a deficient grasp of right and wrong. Ask a psychopath what he is supposed to do in a particular situation, and he can usually give you what non-psychopaths would regard as the correct answer. It is just that he does not seem bound to act on that knowledge. © The Economist Newspaper Limited 2010.

Related chapters from BP7e: Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress
Link ID: 14685 - Posted: 11.16.2010

By Dave Lee BBC World Service Young offenders are more likely to have suffered a brain injury compared with the rest of society, a study suggests. A survey of 197 young male offenders found about half reported having had a childhood brain injury - three times higher than in non-offenders. Multiple head injuries were linked with carrying out more violent crimes, says the University of Exeter team. Better assessment of injuries could help prevent re-offending, they add. The researchers asked 197 offenders aged 11 to 19 years about their past medical history, convicted crimes, mental health and drug use. They considered the effects of traumatic brain injury alongside other factors such as deprivation and lack of life opportunities to determine if a childhood brain injury contributed to future acts of criminal behaviour. The study, published in the journal Neuropsychological Rehabilitation, found that while a brain injury alone is unlikely to increase a child's chances of criminal activity, it could play a factor in those already susceptible to crime, and may increase the chance of repeat offences. "The associations between brain injuries and crime are very problematic," explained Huw Williams, associate professor of clinical neuropsychology at the University of Exeter, on Radio 4's All in the Mind. "It may not be causal in the sense of increasing the chances of crime, but it may well be a factor in terms of re-offending." BBC © MMX

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: 14654 - Posted: 11.11.2010

Repeated viewing of violent scenes in films, television or video games could make teenagers behave more aggressively, US research suggests. The National Institutes of Health study of 22 boys aged 14 to 17 found that showing dozens of violent clips appeared to blunt brain responses. Dr Jordan Grafman said it might make aggression feel more "acceptable". However, a UK expert said the reasons behind violence were too complex to be explained by laboratory research. The effect of violent imagery on young people has been debated from the early days of television, and, more recently, that debate has expanded to include video games. Various studies have suggested that exposure appears to have an effect on the way that the brain processes emotional responses, yet it is unclear whether this can have a direct impact on behaviour. The US study, published in the journal Social Cognitive & Affective Neuroscience, involved 60 violent scenes from videos being collated, mostly involving street brawling and fist fights. The violence was ranked "low", "mild" or "moderate", and there were no "extreme" scenes. BBC © MMX

Related chapters from BP7e: Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress
Link ID: 14567 - Posted: 10.19.2010

By NOAH SNYDER-MACKLER In baboons, a new mother will rarely find herself alone. She will be hounded constantly by other, higher-ranking females who want to look, touch and sometimes steal the infant. But female geladas do not usually show much interest in others’ babies. A newborn gelada never leaves its mother’s chest in the first month, and it spends a majority of its time attached to her until it is about six months old. Mama geladas are extremely protective of their infants, and with good reason. Infanticide appears to be prevalent, especially following a change in dominant male (known as a “takeover”). Male infanticide — the killing of infants by males — is the most common form of infanticide in primates. It has been argued that this is beneficial for newly dominant males because the females will come into estrus sooner, meaning they can produce the new dominant male’s offspring sooner, rather than wait until the former dominant male’s offspring are weaned. There are only a few observed cases of male infanticide in geladas, but our project has found plenty of evidence suggesting that it is common in our study population. I have observed the protectiveness of new gelada mothers. Even though I am not a newly dominant male, nor do I pose a threat, if a curious infant gets too close to me while I am doing behavioral observations, the mother will sprint over, grab her infant and threaten me by flashing her bright pink eyelids. This is when I need to back away. It’s the same response a female will give to another gelada if she perceives that her child is unsafe. Copyright 2010 The New York Times Company

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: 14531 - Posted: 10.07.2010

People who are aggressive may be at higher risk for heart attack or stroke, a new study suggests. The study of 5,614 Italians in Sardinia found that those who scored high for antagonistic traits like competitiveness and aggression on a standard personality test had more thickening of their neck arteries compared with those who were more agreeable. The thickness of this carotid artery is considered a risk factor for heart attack and stroke, researchers said in Monday's online issue of the journal Hypertension: Journal of the American Heart Association. "People who tend to be competitive and more willing to fight for their own self-interest have thicker arterial walls, which is a risk factor for cardiovascular disease," Angelina Sutin, the study's lead author and a postdoctoral fellow with the U.S. National Institute on Aging in Baltimore, Md., said in a news release. "Agreeable people tend to be trusting, straightforward and show concern for others while people who score high on antagonism tend to be distrustful, skeptical and at the extreme, cynical, manipulative, self-centered, arrogant and quick to express anger," she added. When researchers followed up with study participants three years after the initial tests, they found they found the link between artery thickening and antagonism had persisted. © CBC 2010

Related chapters from BP7e: Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress
Link ID: 14368 - Posted: 08.17.2010

by Kristen Minogue "Free-range" chickens are the gold standard for consumers interested in humanely raised livestock. But for most chickens, the wide-open spaces of a free-range poultry farm aren't nearly as idyllic as they sound. The birds often peck at each other's feathers, causing painful scars, bleeding, and even death. Now, researchers have developed a mathematical model that may help farmers stop the pecking before it starts. It's unclear why chickens like to bite the feathers off their neighbors. According to bird-welfare researcher Bas Rodenburg of Wageningen University in the Netherlands, the best explanation is that they've evolved to peck for food in the wild, and this need is not satisfied on the farm. "Instead of pecking at the floor, for instance, they start pecking at each other's feathers," Rodenburg says. Right now, the only way for free-range farmers to prevent the behavior is beak trimming, a euphemism for cutting off the sharp tip of a bird's beak with a hot blade or directing infrared rays into its inner tissue until the tip falls off a few weeks later. To find a better solution, a team of zoologists and engineers studied video recordings of more than 300,000 hens living on free-range farms in the United Kingdom. The researchers applied a mathematical technique called optical flow modeling, which has been used to study traffic patterns and human crowds, to track how the chickens moved in large groups. The process involved analyzing multiple snapshots of the same 50 to 100 hens taken at different times to find patterns of movement that correlate with chicken-on-chicken violence. © 2010 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: 14316 - Posted: 08.03.2010