Female Choice Key to Evolutionary Shift to Modern Family

It is a question that has puzzled evolutionary biologists for years: Why did we stop being promiscuous and decide to settle down to start families?

Sergey Gavrilets, professor of ecology and evolutionary biology at the University of Tennessee, Knoxville, may have found the answer, and it lies in the power of female choice. The study reveals how females chose their mates played a critical role in human evolution by leading to monogamous relationships, which laid the foundation for the institution of the modern family.

Using mathematical modeling, the associate director for scientific activities at the National Institute for Mathematical and Biological Synthesis (NIMBioS) at UT has discovered that the transformation may have occurred when early-hominid females started choosing males who were good providers.

Gavrilets' findings are published in the Proceedings of the National Academy of Sciences.

The "sexual revolution" entailed males first competing with other males for dominance, as a way to get matings. However, low-ranked males—and eventually all males except those with the highest societal stature—began supplying females with provisions in what is called "food-for-mating" to get a leg up on the competition. Females showed preference for the "provisioning" males, leading males' energy to be spent on providing for females and females becoming increasingly faithful. This spurred self-domestication and the modern family as we know it today.

"This change has confounded scientists for a long time because many species would be much better off evolutionarily if the effort spent on males competing for mates was redirected towards increasing female fertility or survivorship of their offspring," said Gavrilets.

The study demonstrates mathematically that the most commonly proposed theories for the transition to human pair bonding—or coupling—are not biologically feasible.

However, the study advances a new model showing that the transition to pair-bonding can occur when female choice and faithfulness, among other factors, are included. The result is an increased emphasis on males provisioning females over male competition for mating.

"The study reveals that female choice played a crucial role in human evolution," said Gavrilets.

According to Gavrilets, the transition to coupling has opened the path to intensified male parental investment, which was a breakthrough adaptation with multiple anatomical, behavioral and physiological consequences for early hominids and for all of their descendants. It shifted the dynamic away from males competing with each other for sex to males competing with each other to see who is a better provider to get better mates.

"Pair bonding laid the foundation for a later emergence of the institution of the modern family," said Gavrilets.

Source: University of Tennessee [May 30, 2012]

Read more »

Stressed Men Are More Social

Freiburg researchers have refuted the common belief that stress always causes aggressive behavior. A team of researchers led by the psychologists and neuroscientists Prof. Markus Heinrichs and Dr. Bernadette von Dawans at the University of Freiburg, Germany, examined in a study how men react in stressful situations -- and have refuted a nearly 100-year-old doctrine with their results.

According to this doctrine, humans and most animal species show the "fight-or-flight" response to stress. Only since the late 1990s have some scientists begun to argue that women show an alternate "tend-and-befriend" response to stress -- in other words, a protective ("tend") and friendship-offering ("befriend") reaction. Men, in contrast, were still assumed to become aggressive under stress. Von Dawans refuted this assumption, saying: "Apparently men also show social approach behavior as a direct consequence of stress."

With this study, the research team experimentally investigated male social behavior under stress for the first time. The results are published in the  journal Psychological Science. The economists Prof. Ernst Fehr of the University of Zurich, Switzerland, and Prof. Urs Fischbacher of the University of Konstanz, Germany, as well as the psychologist Prof. Clemens Kirschbaum from the Technical University of Dresden, Germany, also participated in the study. Last year, Heinrichs and von Dawans already developed a standardized procedure for inducing stress in groups using a public speaking task. The researchers examined the implications of this stressor for social behavior using specially designed social interaction games.. These games allowed them to measure positive social behavior -- for example, trust or sharing -- and negative social behavior -- for example, punishment.

In the study, subjects who were under stress showed significantly more positive social behavior than control subjects who were not in a stressful situation. Negative social behavior, on the other hand, was not affected by stress. For Markus Heinrichs, this has far-reaching consequences for our understanding of the social significance of stress: "From previous studies in our laboratory, we already knew that positive social contact with a trusted individual before a stressful situation reduces the stress response. Apparently, this coping strategy is anchored so strongly that people can also change their stress responses during or immediately after the stress through positive social behavior."

Source: Albert-Ludwigs-Universität Freiburg [May 21, 2012]

Read more »

Teamwork linked to intelligence

Learning to work in teams may explain why humans evolved a bigger brain, according to a new study published on Wednesday. 

Learning to work in teams may explain why humans evolved a bigger brain [Credit: AFP]

Compared to his hominid predecessors, Homo sapiens is a cerebral giant, a riddle that scientists have long tried to solve. 

The answer, according to researchers in Ireland and Scotland, may lie in social interaction. 

Working with others helped Man to survive, but he had to develop a brain big enough to cope with all the social complexities, they believe. 

In a computer model, the team simulated the human brain, allowing a network of neurons to evolve in response to a series of social challenges. 

There were two scenarios. The first entailed two partners in crime who had been caught by the police, each having to decide whether or not to inform on the other. 

The second had two individuals trapped in a car in a snowdrift and having to weigh whether to cooperate to dig themselves out or just sit back and let the other do it. 

In both cases, the individual would gain more from selfishness. 

But the researchers were intrigued to find that as the brain evolved, the individual was likelier to choose to cooperate. 

"We cooperate in large groups of unrelated individuals quite frequently, and that requires cognitive abilities to keep track of who is doing what to you and change your behaviour accordingly," co-author Luke McNally of Dublin's Trinity College told AFP. 

McNally pointed out, though, that cooperation has a calculating side. We do it out of reciprocity. 

"If you cooperate and I cheat, then next time we interact you could decide: 'Oh well, he cheated last time, so I won't cooperate with him.' So basically you have to cooperate in order to receive cooperation in the future." 

McNally said teamwork and bigger brainpower fed off each other. 

"Transitions to cooperative, complex societies can drive the evolution of a bigger brain," he said. 

"Once greater levels of intelligence started to evolve, you saw cooperation going much higher." 

The study appears in Proceedings of the Royal Society B, a journal published by Britain's de-facto academy of sciences. 

Commenting on the paper, Robin Dunbar, an evolutionary anthropologist at Oxford University, said the findings were a valuable add to understanding brain evolution. 

But he said there were physiological limits to cooperation. 

Man would need a "house-sized brain" to take cooperation to a perfect level on a planet filled with humans. 

"Our current brain size limits the community size that we can manage ... that we feel we belong to," he said. 

Our comfortable "personal social network" is limited to about 150, and boosting that to 500 would require a doubling of the size of the brain. 

"In order to create greater social integration, greater social cohesion even on the size of France, never mind the size of the EU, never mind the planet, we probably have to find other ways of doing it" than wait for evolution, said Dunbar. 

Source: AFP [April 11, 2012]

Read more »

Do I look bigger with my finger on a trigger? Yes, says study

UCLA anthropologists asked hundreds of Americans to guess the size and muscularity of four men based solely on photographs of their hands holding a range of easily recognizable objects, including handguns. 

Photo from study. Holding a gun like this makes a man appear taller and stronger than he would otherwise, UCLA anthropologists have found [Credit: Daniel Fessler/UCLA]

The research, which publishes April 11 in the scholarly journal PLoS ONE, confirms what scrawny thugs have long known: Brandishing a weapon makes a man appear bigger and stronger than he would otherwise. 

"There's nothing about the knowledge that gun powder makes lead bullets fly through the air at damage-causing speeds that should make you think that a gun-bearer is bigger or stronger, yet you do," said Daniel Fessler, the lead author of the study and an associate professor of anthropology at UCLA. "Danger really does loom large -- in our minds." 

Researchers say the findings suggest an unconscious mental mechanism that gauges a potential adversary and then translates the magnitude of that threat into the same dimensions used by animals to size up their adversaries: size and strength. 

"We've isolated a capacity to assess threats in a simple way," said Colin Holbrook, a UCLA postdoctoral scholar in anthropology and co-author of the study. "Though this capacity is very efficient, it can misguide us." 

The study is part of larger project funded by the U.S. Air Force Office of Scientific Research to understand how people make decisions in situations where violent conflict is a possibility. The findings are expected to have ramifications for law enforcement, prison guards and the military. 

"We're exploring how people think about the relative likelihood that they will win a conflict, and then how those thoughts affect their decisions about whether to enter into conflict," said Fessler, whose research focuses on the biological and cultural bases of human behavior. He is the director of UCLA's Center for Behavior, Evolution and Culture, an interdisciplinary group of researchers who explore how various forms of evolution shape behavior. 

For the study, the UCLA researchers recruited participants in multiple rounds using classified advertisements on the websites Craigslist and MechanicalTurk. In one round, 628 individuals were asked to look at four pictures of different hands, each holding a single object: a caulking gun, electric drill, large saw or handgun. 

"Tools were used as control objects to rule out the possibility that a simple link with traditionally masculine objects would explain intuitions that the weapon-holders were larger and stronger," Fessler explained. 

The individuals were then asked to estimate the height of each hand model in feet and inches based solely on the photographs of their hands. Participants also were shown six images of progressively taller men and six images of progressively more muscular men and asked to estimate which image came closest to the probable size and strength of the hand model. 

Study participants consistently judged pistol-packers to be taller and stronger than the men holding the other objects, even though the experiment's four hand models were recruited on the basis of their equivalent hand size and similar hand appearance (white and without identifying marks such as tattoos or scars). 

To rule out the possibility that a feature of any one hand might influence the estimates, researchers had taken separate pictures of each hand holding each object -- some participants saw the gun held by one hand model, others saw the same gun held by another model, and so on; they did the same thing for each of the objects. The researchers also shuffled the order in which the photos were presented. 

On average, participants judged pistol packers to be 17 percent taller and stronger than those judged to be the smallest and weakest men -- the ones holding caulking guns. Hand models holding the saw and drill followed gun-wielders in size and strength. 

"The function of the system is to provide an easy way for people to assess the likelihood that they would win or lose in a conflict," said Jeffrey K. Snyder, a UCLA graduate student in anthropology and a study co-author. 

Concerned that their findings might be influenced by popular culture, which often depicts gun-slingers as big and strong men, the team conducted two more studies using objects that did not seem to have a macho image: a kitchen knife, a paint brush and a large, brightly colored toy squirt gun. In the initial round, a new group of 100 subjects was asked to evaluate the danger posed by each of the objects (which were presented alone, without hands holding them). They then were asked to pick the type of person most associated with the object: a child, a woman or a man. 

Not surprisingly, individuals rated the knife most dangerous, followed by the paint brush and squirt gun. But where the most lethal object in the earlier studies -- the handgun -- would likely have been associated with men, participants in this study most often associated the most lethal object -- the kitchen knife -- with women. The paint brush was most often associated with men, and the squirt gun with children. 

In the final round of tests, a new group of 541 individuals was shown male hands holding the knife, paint brush and squirt gun and was then asked to estimate the height and muscularity of the hand models. Once again, men holding the most lethal object -- in this case, the kitchen knife -- were judged to be the biggest and strongest, followed by those holding the paint brush and the squirt gun. 

"It's not Dirty Harry's or Rambo's handgun -- it's just a kitchen knife, but it's still deadly," Holbrook said. "And our study subjects responded accordingly, estimating its holder to be bigger and stronger than the rest." 

Author: Meg Sullivan | Source: University of California - Los Angeles [April 11, 2012]

Read more »

Does religious faith lead to greater rewards here on Earth?

Delayed gratification: People who are good at overcoming their immediate impulses to take small rewards now — in favor of larger rewards down the road — do better in many areas of life, including academic achievement, income, job performance and health. What life experiences develop this ability? A new study published online, ahead of print, by the journal of Evolution and Human Behavior, finds that religious people are better able to forgo immediate satisfaction in order to gain larger rewards in the future. The study is the first to demonstrate an association between religious commitment and a stronger preference for delayed, but more significant, rewards. 

"It's possible to analyze virtually all contemporary social concerns, from excessive credit card debt to obesity, as problems of impulsivity. So the fact that religious people tend to be less impulsive has implications for the sorts of decisions they make with their money, time, and other resources," says Michael McCullough, professor of Psychology in the College of Arts and Sciences at the University of Miami (UM), and principal investigator of this study. "Their tendency toward less impulsive decision-making might even be relevant to their stands on public policy issues, such as whether governments should be seeking to reduce their expenditures on public services and entitlement programs in the current economic environment." 

In the research work, titled "Religious people discount the future less," 277 undergraduate University students, from a variety of religious denominations and ethnic backgrounds, chose between receiving a small financial monetary reward that the investigators made available immediately--for example "$50 today," or a larger reward that was available only after longer amounts of time had passed—for example, "$100 six months from now." Participants' commitment to their religious beliefs and institutions was also measured, among other relevant variables. The data shows that the extent to which the participants follow religious teachings positively correlates with their ability to delay gratification. 

The findings suggest that through religious beliefs and practices, people "develop a more patient style of decision making." According to the study, religion teaches this type of patience by directing people's attention to the distant future—the afterlife—which may cause their nearer-term future on this earth to feel subjectively closer. 

"People who are intrinsically religious and who indicate an interest in the afterlife tend to report that the future feels as though it is approaching quickly and that they spend a lot of time thinking about the future," the study says. 

Source: University of Miami [April 04, 2012]

Read more »

Death anxiety increases atheists' unconscious belief in God

New research suggests that when non-religious people think about their own death they become more consciously skeptical about religion, but unconsciously grow more receptive to religious belief. 

The research, from the Department of Psychology at the University of Otago in New Zealand, also found that when religious people think about death, their religious beliefs appear to strengthen at both conscious and unconscious levels. The researchers believe the findings help explain why religion is such a durable feature of human society. 

In three studies, which involved 265 university students in total, religious and non-religious participants were randomly assigned to "death priming" and control groups. Priming involved asking participants to write about their own death or, in the control condition, about watching TV. 

In the first study, researchers found that death-primed religious participants consciously reported greater belief in religious entities than similar participants who had not been death-primed. Non-religious participants who had been primed showed the opposite effect: they reported greater disbelief than their fellow non-religious participants in the control condition. 

Study co-author Associate Professor Jamin Halberstadt says these results fit with the theory that fear of death prompts people to defend their own worldview, regardless of whether it is a religious or non-religious one. 

"However, when we studied people's unconscious beliefs in the two later experiments, a different picture emerged. While death-priming made religious participants more certain about the reality of religious entities, non-religious participants showed less confidence in their disbelief," Associate Professor Halberstadt says. 

The techniques used to study unconscious beliefs include measuring the speed with which participants can affirm or deny the existence of God and other religious entities. After being primed by thoughts of death, religious participants were faster to press a button to affirm God's existence, but non-religious participants were slower to press a button denying God's existence. 

"These findings may help solve part of the puzzle of why religion is such a persistent and pervasive feature of society. Fear of death is a near-universal human experience and religious beliefs are suspected to play an important psychological role in warding off this anxiety. As we now show, these beliefs operate at both a conscious and unconscious level, allowing even avowed atheists to unconsciously take advantage of them." 

The paper co-authors also included Jonathan Jong, currently at the University of Oxford, who undertook the experiments as part of his PhD thesis, and Matthias Bluemke, currently at the University of Heidelberg. Associate Professor Halberstadt was Jong's supervisor. 

The findings from the three experiments will be published in the Journal of Experimental Social Psychology. 

Source: University of Otago [April 01, 2012]

Read more »

Dare you protest against God?

Is it OK to protest God's actions—or inactions? This was the key question behind recent studies led by Case Western Reserve University psychologist Julie Exline. 

Many people report having a relationship with God, similar to those relationships in marriage, parenting or friendship. Exline and colleagues found that being assertive with God could actually strengthen that perceived bond and one's faith. 

They report their findings in the journal Psychology of Religion and Spirituality's article, "Anger, Exit and Assertion: Do People See Protest toward God as Morally Acceptable?" 

Using Internet surveys, the research focused on two groups: 358 undergraduates at a research university and 471 participants from a broad-based group of adults. Although a variety of faiths were represented, the analyses focused only on people with some belief in God. 

The researchers discovered if a person views God as cruel, then protest toward God is seen as more acceptable. 

"If God seems like a bully or a tyrant, standing up to God could be seen as an act of courage or even heroism," says Exline. 

But when people see God as a kind and loving authority figure, then protest seems less acceptable. "In this case, protest could appear disrespectful to a good and fair leader," says Exline. 

Exline suggests that it's important to analyze different types of protest. 

The researchers found that many believers think that it's morally OK to be assertive by asking God questions or complaining. But they're less sure about whether anger toward God is acceptable. 

"The larger step of leaving the relationship is clearly seen as wrong by most people of faith," Exline says. "Exiting the relationship can entail outright rejection of God, holding onto anger, questioning God's authority, rebelling, or withdrawing from the relationship." 

"We can think about the parallel to a human relationship," says Exline. "Good relationships usually leave room for honest communications, including some complaint and disagreement. People tend to feel most close and happy with their partners when they have some sense of 'voice' in a relationship. This doesn't mean yelling or screaming, but showing respect and honesty with each other about their feelings—including those of anger and frustration." 

A related question was addressed in the recent Journal of Psychology and Theology's article, "If I Tell Others about My Anger Toward God, How Will They Respond?" Drawing from the same Internet survey of adult believers, she focused only on those who felt some anger toward God. 

If people felt that it was morally OK to feel angry with God, they were more likely to reveal their feelings to others. 

Most people reported supportive responses, Exline says, but it was also common for people to receive unsupportive responses that made them feel judged, ashamed or guilty about their feelings. 

"When people saw others as supportive, they were more likely to report that they had approached God with their feelings—and they were more likely to report strengthened faith in response to the incident," said Exline. "On the other hand, people who reported unsupportive responses from others were more likely to suppress their feelings toward God rather than dealing with them openly. They tended to stay angry with God and were more likely to exit the relationship. They also reported greater use of alcohol and drugs to cope with the problem." 

Exline advises that if someone comes to you and tells you that they are mad at God, the type of response that you provide could be important in terms of shaping what happens. 

"Regardless of whether you think that anger toward God is right or wrong, it's important to respond in a way that helps the other person feel supported rather than shamed," Exline says.  

Source: Case Western Reserve University [March 26, 2012]

Read more »

Recent Generations Focus More On Fame, Money Than Giving Back

The times are changing, and not necessarily for the better when it comes to giving back to society, according to 40 years of research on 9 million young adults. Since the baby boomer generation, there has been a significant decline among young Americans in political participation, concern for others and interest in saving the environment, according to a new study published by the American Psychological Association. 

"Popular views of the millennial generation, born in the 1980s and 1990s, as more caring, community-oriented and politically engaged than previous generations are largely incorrect, particularly when compared to baby boomers and Generation X at the same age," said the study's lead author, Jean Twenge, PhD, a psychology professor at San Diego State University and author of the book, "Generation Me." "These data show that recent generations are less likely to embrace community mindedness and are focusing more on money, image and fame." The study was published online this month in APA's Journal of Personality and Social Psychology. 

The findings did show that millennials were more likely than baby boomers or Generation Xers to volunteer during high school and to say that they intend to participate in community service in college. However, the authors contend that this trend is most likely related to schools' requiring community service for graduation, which has been cited in numerous studies. The desire to save the environment, an area considered to be of particular concern to millennials, showed some of the largest declines, with three times as many millennials as baby boomers at the same age saying they made no personal effort to help the environment. Fifty-one percent of millennials said they made an effort to cut down on electricity use to save energy, compared to 68 percent of boomers in the 1970s. 

Twenge and her colleagues analyzed data from the University of Michigan's Monitoring the Future study of high school seniors, conducted continuously since 1975, and the American Freshman survey by UCLA's Higher Education Research Institute of entering college students since 1966. Both surveys included items on life goals, concern for others, and civic and community involvement. 

In the American Freshman survey, the proportion of students who said being wealthy was very important to them increased from 45 percent for baby boomers (surveyed between 1966 and 1978) to 70 percent for Generation Xers (surveyed between 1979 and 1999) and 75 percent for millennials (surveyed between 2000 and 2009). Likewise, the proportion who said it was important to keep up to date with political affairs decreased, from 50 percent for boomers to 39 percent for Generation Xers and 35 percent for millennials. "Becoming involved in programs to clean up the environment" decreased, from 33 percent for boomers to 20 percent for millennials. "Developing a meaningful philosophy of life" decreased the most across generations, from 73 percent for boomers to 45 percent for millennials. 

"These data suggest that the 'Me Generation' label affixed to the baby boomers was unwarranted. In comparison to the proceeding generations, the boomers look significantly more selfless," Twenge said. "The generational trends toward more political disengagement, less environmental concern and more materialistic values could have a meaningful impact on society. It will be interesting to see how millennials are affected by the recent recession and whether future generations will reverse the trends." 

The American Psychological Association, in Washington, D.C., is the largest scientific and professional organization representing psychology in the United States and is the world's largest association of psychologists. APA's membership includes more than 154,000 researchers, educators, clinicians, consultants and students. Through its divisions in 54 subfields of psychology and affiliations with 60 state, territorial and Canadian provincial associations, APA works to advance psychology as a science, as a profession and as a means of promoting health, education and human welfare. 

Source: American Psychological Association (APA) [March 15, 2012]

Read more »

Low socioeconomic status means worse health -- but not for everyone

Poverty is bad for your health. Poor people are much more likely to have heart disease, stroke, and cancer than wealthy people, and have a lower life expectancy, too. Children who grow up poor are more likely to have health problems as adults. 

But despite these depressing statistics, many children who grow up poor have good health. In a new article published in Perspectives on Psychological Science, a journal of the Association for Psychological Science, Edith Chen and Gregory E. Miller of the University of British Columbia suggest a possible reason: some children have role models who teach them to cope with stress. 

"Who are these bright spots who, despite a lot of adversity, make it through and do well?" Chen asked. She suspects the answer has to do with stress. Growing up poor can be stressful, and stress increases the risk of developing chronic diseases. Poor children are less likely to have a predictable routine and a stable home; their parents may have to work multiple jobs to make ends meet and may not be able to afford to fix a leaky roof, for example. Poor children are also more likely to experience violence. One study found that nearly 50% of low income youth had witnessed a murder. 

In the face of this stress, Miller and Chen propose a strategy that may work to reduce stress and improve health. They call it "shift-and-persist." The first part, "shift," means reappraising things that are stressful. For example, if you get fired from a job, you can feel miserable and lash out at people around you—or you can reassess the situation to find the bright side. "You think, 'I wouldn't choose this, but maybe it's an opportunity to end up in a better job down the line,'" Chen says. Research on children growing up in adversity has found that children do well if they can self-regulate like this. 

But it's not enough to accept stressful situations. The second part, "persist," has to do with staying positive in the longer term—"holding out hope and finding a broader meaning in your life," Chen says. Shifting perspective on a particular situation helps in the short term, but, she says, "You have to do that with the idea that there's a broader goal in mind." Many studies have found that finding meaning helps people get through difficult situations, like spinal injuries or collective traumatic experiences like the September 11, 2001 terrorist attacks. 

The way most children learn "shift-and-persist" may be through positive role models, Chen says. Parents, teachers, aunts, and other adults can model healthy ways of dealing with stress and also teach children a sense of optimism about the world. 

The goal, of course, is to extend this help to other children. There are some hints that it may be possible to use community leaders to improve health, Chen says. "For example, in kids with asthma, if you get people in the community to serve as lay coaches for the parents, that can be beneficial to the kids," she says. It may also be possible to use role models in the community to teach more children to reappraise their stress and think positively about the future.  

Source: Association for Psychological Science [March 21, 2012]

Read more »

Could brain size determine whether you are good at maintaining friendships?

Researchers are suggesting that there is a link between the number of friends you have and the size of the region of the brain – known as the orbital prefrontal cortex – that is found just above the eyes. A new study, published today in the journal Proceedings of the Royal Society B, shows that this brain region is bigger in people who have a larger number of friendships. 

The research was carried out as part of the British Academy Centenary ‘Lucy to Language’ project, led by Professor Robin Dunbar of the University of Oxford in a collaboration with Dr Penny Lewis at The University of Manchester, Dr Joanne Powell and Dr Marta Garcia-Finana at Liverpool University, and Professor Neil Roberts at Edinburgh University. 

The study suggests that we need to employ a set of cognitive skills to maintain a number of friends (and the keyword is ‘friends’ as opposed to just the total number of people we know). These skills are described by social scientists as ‘mentalising’ or ‘mind-reading’– a capacity to understand what another person is thinking, which is crucial to our ability to handle our complex social world, including the ability to hold conversations with one another. This study, for the first time, suggests that our competency in these skills is determined by the size of key regions of our brains (in particular, the frontal lobe). 

Professor Dunbar, from the Institute of Cognitive and Evolutionary Anthropology, explained: “’Mentalising’ is where one individual is able to follow a natural hierarchy involving other individuals’ mind states. For example, in the play ‘Othello’, Shakespeare manages to keep track of five separate mental states: he intended that his audience believes that Iago wants Othello to suppose that Desdemona loves Cassio [the italics signify the different mind states]. Being able to maintain five separate individuals’ mental states is the natural upper limit for most adults.” 

The researchers took anatomical MR images of the brains of 40 volunteers at the Magnetic Resonance and Image Analysis Research Centre at the University of Liverpool to measure the size of the prefrontal cortex, the part of the brain used in high-level thinking. Participants were asked to make a list of everyone they had had social, as opposed to professional, contact with over the previous seven days. They also took a test to determine their competency in mentalising.  

Professor Dunbar said: “We found that individuals who had more friends did better on mentalising tasks and had more neural volume in the orbital frontal cortex, the part of the forebrain immediately above the eyes. Understanding this link between an individual’s brain size and the number of friends they have helps us understand the mechanisms that have led to humans developing bigger brains than other primate species. The frontal lobes of the brain, in particular, have enlarged dramatically in humans over the last half million years.” 

Dr Penny Lewis, from the School of Psychological Sciences at The University of Manchester, said: “Both the number of friends people had and their ability to think about other people’s feelings predicted the size of this same small brain area. This not only suggests that we’ve found a region which is critical for sociality, it also shows that the link between brain anatomy and social success is much more direct than previously believed.” 

Dr Joanne Powell, from the Department of Psychology, University of Liverpool, said: “Perhaps the most important finding of our study is that we have been able to show that the relationship between brain size and social network size is mediated by mentalising skills. What this tells us is that the size of your brain determines your social skills, and it is these that allow you to have many friends.” 

Dr Lewis added: “This research is particularly important because it provides the strongest support to date for the social brain hypothesis – that is, the idea that human brains evolved to accommodate the social demands of living in a big group. Cross-species comparisons between various monkey brains have already supported this, but our work is some of the first to show that people with larger social groups actually have more neural matter in this particular bit of cortex. It looks as though size really does matter when it comes to social success.” 

Source: University of Manchester [February 02, 2012]

Read more »

Testosterone Makes Us Less Cooperative and More Egocentric

Testosterone makes us overvalue our own opinions at the expense of cooperation, research from the Wellcome Trust Centre for Neuroimaging at UCL (University College London) has found. The findings may have implications for how group decisions are affected by dominant individuals. 

Problem solving in groups can provide benefits over individual decisions as we are able to share our information and expertise. However, there is a tension between cooperation and self-orientated behaviour: although groups might benefit from a collective intelligence, collaborating too closely can lead to an uncritical groupthink, ending in decisions that are bad for all. 

Attempts to understand the biological mechanisms behind group decision making have tended to focus on the factors that promote cooperation, and research has shown that people given a boost of the hormone oxytocin tend to be cooperative. Now, in a study recently published in the journal Proceedings of the Royal Society B, researchers have shown that the hormone testosterone has the opposite effect -- it makes people act less cooperatively and more egocentrically. 

Dr Nick Wright and colleagues at the Wellcome Trust Centre for Neuroimaging at UCL carried out a series of tests using 17 pairs of female volunteers* who had previously never met. The test took place over two days, spaced a week apart. On one of the days, both volunteers in each pair were given a testosterone supplement; on the other day, they were given a placebo. 

During the experiment, both women sat in the same room and viewed their own screen. Both individuals saw exactly the same thing. First, in each trial they were shown two images, one of which contained a high-contrast target -- and their job was to decide individually which image contained the target. 

If their individual choices agreed, they received feedback and moved on to the next trial. However, if they disagreed, they were asked to collaborate and discuss with their partner to reach a joint decision. One of the pair then input this joint decision. 

The researchers found that, as expected, cooperation enabled the group to perform much better than the individuals alone when individuals had received only the placebo. But, when given a testosterone supplement, the benefit of cooperation was markedly reduced. In fact, higher levels of testosterone were associated with individuals behaving egocentrically and deciding in favour of their own selection over their partner's. 

"When we are making decisions in groups, we tread a fine line between cooperation and self-interest: too much cooperation and we may never get our way, but if we are too self-orientated, we are likely to ignore people who have real insight," explains Dr Wright. 

"Our behaviour seems to be moderated by our hormones -- we already know that oxytocin can make us more cooperative, but if this were the only hormone acting on our decision-making in groups, this would make our decisions very skewed. We have shown that, in fact, testosterone also affects our decisions, by making us more egotistical. 

"Most of the time, this allows us to seek the best solution to a problem, but sometimes, too much testosterone can help blind us to other people's views. This can be very significant when we are talking about a dominant individual trying to assert his or her opinion in, say, a jury." 

Testosterone is implicated in a variety of social behaviours. For example, in chimpanzees, levels of testosterone rise ahead of a confrontation or a fight. In female prisoners, studies have found that higher levels of testosterone correlate with increased antisocial behaviour and higher aggression. Researchers believe that such findings reflect a more general role for testosterone in increasing the motivation to dominate others and increase egocentricity. 

Commenting on the findings, Dr John Williams, Head of Neuroscience and Mental Health at the Trust, said: "Cooperating with others has obvious advantages for sharing skills and experience, but we know it doesn't always work, particularly if one alpha male or alpha female dominates the decision making. This result helps us understand at a hormonal level the factors that can disrupt our attempts to work together." 

The Wellcome Trust funded this study. 

*Testosterone is naturally secreted in men and women, and testosterone levels are correlated with important behaviours (e.g. antisocial behaviour) in both men and women. For the size of dose given experimentally, in women this markedly increases their testosterone from its low baseline level. In men, however, the situation is more complicated: men already have high baseline levels of testosterone, so giving such doses will decrease their own production of testosterone, a feedback effect that will act to offset the increase caused by the treatment itself. The researchers therefore used female subjects because giving standard experimental doses causes a straightforward and well-characterised increase in their testosterone levels. 

Source: Wellcome Trust [January 31, 2012]

Read more »

What Are Emotion Expressions For?

That cartoon scary face – wide eyes, ready to run – may have helped our primate ancestors survive in a dangerous wild, according to the authors of an article published in Current Directions in Psychological Science, a journal of the Association for Psychological Science. The authors present a way that fear and other facial expressions might have evolved and then come to signal a person’s feelings to the people around him. 

The basic idea, according to Azim F. Shariff of the University of Oregon, is that the specific facial expressions associated with each particular emotion evolved for some reason. Shariff cowrote the paper with Jessica L. Tracy of the University of British Columbia. So fear helps respond to threat, and the squinched-up nose and mouth of disgust make it harder for you to inhale anything poisonous drifting on the breeze. The outthrust chest of pride increases both testosterone production and lung capacity so you’re ready to take on anyone. Then, as social living became more important to the evolutionary success of certain species—most notably humans—the expressions evolved to serve a social role as well; so a happy face, for example, communicates a lack of threat and an ashamed face communicates your desire to appease. 

The research is based in part on work from the last several decades showing that some emotional expressions are universal—even in remote areas with no exposure to Western media, people know what a scared face and a sad face look like, Shariff says. This type of evidence makes it unlikely that expressions were social constructs, invented in Western Europe, which then spread to the rest of the world. 

And it’s not just across cultures, but across species. “We seem to share a number of similar expressions, including pride, with chimpanzees and other apes,” Shariff says. This suggests that the expressions appeared first in a common ancestor. 

The theory that emotional facial expressions evolved as a physiological part of the response to a particular situation has been somewhat controversial in psychology; another article in the same issue of Current Directions in Psychological Science argues that the evidence on how emotions evolved is not conclusive. 

Shariff and Tracy agree that more research is needed to support some of their claims, but that, “A lot of what we’re proposing here would not be all that controversial to other biologists,” Shariff says. “The specific concepts of ‘exaptation’ and ‘ritualization’ that we discuss are quite common when discussing the evolution of non-human animals.” For example, some male birds bring a tiny morsel of food to a female bird as part of an elaborate courtship display. In that case, something that might once have been biologically relevant—sharing food with another bird—has evolved over time into a signal of his excellence as a potential mate. In the same way, Shariff says, facial expressions that started as part of the body’s response to a situation may have evolved into a social signal. 

Source: Association for Psychological Science [December 22, 2011]

Read more »

Research states that prejudice comes from a basic human need and way of thinking

Where does prejudice come from? Not from ideology, say the authors of a new paper. Instead, prejudice stems from a deeper psychological need, associated with a particular way of thinking. People who aren’t comfortable with ambiguity and want to make quick and firm decisions are also prone to making generalizations about others. 

In a new article published in Current Directions in Psychological Science, a journal of the Association for Psychological Science, Arne Roets and Alain Van Hiel of Ghent University in Belgium look at what psychological scientists have learned about prejudice since the 1954 publication of an influential book, The Nature of Prejudice by Gordon Allport. 

People who are prejudiced feel a much stronger need to make quick and firm judgments and decisions in order to reduce ambiguity. “Of course, everyone has to make decisions, but some people really hate uncertainty and therefore quickly rely on the most obvious information, often the first information they come across, to reduce it” Roets says. That’s also why they favor authorities and social norms which make it easier to make decisions. Then, once they’ve made up their mind, they stick to it. “If you provide information that contradicts their decision, they just ignore it.” 

Roets argues that this way of thinking is linked to people’s need to categorize the world, often unconsciously. “When we meet someone, we immediately see that person as being male or female, young or old, black or white, without really being aware of this categorization,” he says. “Social categories are useful to reduce complexity, but the problem is that we also assign some properties to these categories. This can lead to prejudice and stereotyping.” 

People who need to make quick judgments will judge a new person based on what they already believe about their category. “The easiest and fastest way to judge is to say, for example, ok, this person is a black man. If you just use your ideas about what black men are generally like, that’s an easy way to have an opinion of that person,” Roets says. “You say, ‘he’s part of this group, so he’s probably like this.’” 

It’s virtually impossible to change the basic way that people think. Now for the good news: It’s possible to actually also use this way of thinking to reduce people’s prejudice. If people who need quick answers meet people from other groups and like them personally, they are likely to use this positive experience to form their views of the whole group. “This is very much about salient positive information taking away the aversion, anxiety, and fear of the unknown,” Roets says. 

Roets’s conclusions suggest that the fundamental source of prejudice is not ideology, but rather a basic human need and way of thinking. “It really makes us think differently about how people become prejudiced or why people are prejudiced,” Roets says. “To reduce prejudice, we first have to acknowledge that it often satisfies some basic need to have quick answers and stable knowledge people rely on to make sense of the world.” 

Author: Divya Menon | Source: American Psychiatric Association [December 19, 2011]

Read more »

Brain's Failure to Appreciate Others May Permit Human Atrocities

A father in Louisiana bludgeoned and beheaded his disabled 7-year-old son last August because he no longer wanted to care for the boy. For most people, such a heinous act is unconscionable. 

But it may be that a person can become callous enough to commit human atrocities because of a failure in the part of the brain that's critical for social interaction. A new study by researchers at Duke University and Princeton University suggests this function may disengage when people encounter others they consider disgusting, thus "dehumanizing" their victims by failing to acknowledge they have thoughts and feelings. 

This shortcoming also may help explain how propaganda depicting Tutsi in Rwanda as cockroaches and Hitler's classification of Jews in Nazi Germany as vermin contributed to torture and genocide, the study said. 

"When we encounter a person, we usually infer something about their minds. Sometimes, we fail to do this, opening up the possibility that we do not perceive the person as fully human," said lead author Lasana Harris, an assistant professor in Duke University's Department of Psychology & Neuroscience and Center for Cognitive Neuroscience. Harris co-authored the study with Susan Fiske, a professor of psychology at Princeton University. 

Social neuroscience has shown through MRI studies that people normally activate a network in the brain related to social cognition -- thoughts, feelings, empathy, for example -- when viewing pictures of others or thinking about their thoughts. But when participants in this study were asked to consider images of people they considered drug addicts, homeless people, and others they deemed low on the social ladder, parts of this network failed to engage. 

What's especially striking, the researchers said, is that people will easily ascribe social cognition -- a belief in an internal life such as emotions -- to animals and cars, but will avoid making eye contact with the homeless panhandler in the subway. 

"We need to think about other people's experience," Fiske said. "It's what makes them fully human to us." 

The duo's previous research suggested that a lack of social cognition can be linked to not acknowledging the mind of other people when imagining a day in their life, and rating them differently on traits that we think differentiate humans from everything else. 

This latest study expands on that earlier work to show that these traits correlate with activation in brain regions beyond the social cognition network. These areas include those brain areas involved in disgust, attention and cognitive control. 

The result is what the researchers call "dehumanized perception," or failing to consider someone else's mind. Such a lack of empathy toward others can also help explain why some members of society are sometimes dehumanized, they said. 

For this latest study, 119 undergraduates from Princeton completed judgment and decision-making surveys as they viewed images of people. The researchers sought to examine the students' responses to common emotions triggered by images such as: 

• a female college student and male American firefighter (pride)

• a business woman and rich man (envy)

• an elderly man and disabled woman (pity)

• a female homeless person and male drug addict (disgust). 

After imagining a day in the life of the people in the images, participants next rated the same person on various dimensions. They rated characteristics including the warmth, competence, similarity, familiarity, responsibility of the person for his/her situation, control of the person over their situation, intelligence, complex emotionality, self-awareness, ups-and-downs in life, and typical humanity. 

Participants then went into the MRI scanner and simply looked at pictures of people. 

The study found that the neural network involved in social interaction failed to respond to images of drug addicts, the homeless, immigrants and poor people, replicating earlier results. 

"These results suggest multiple roots to dehumanization," Harris said. "This suggests that dehumanization is a complex phenomenon, and future research is necessary to more accurately specify this complexity." 

The sample's mean age was 20, with 62 female participants. The ethnic composition of the Princeton students who participated in the study was 68 white, 19 Asian, 12 of mixed descent, and 6 black, with the remainder not reporting. 

Source: Duke University [December 14, 2011]

Read more »

Xenotransplantation: using pigs as organ and tissue donors for humans

Transplantation is the best available treatment for many serious health problems including diabetes, kidney failure and heart disease. These conditions affect millions of people worldwide and the cost of treatment, loss of productivity and reduced quality of life are enormously expensive to society. 

Pigs may be the answer to Australia’s organ donor shortage [Credit: Thornypup]

Although transplantation offers a lifeline to these patients, there is far greater demand for organs and tissues than can ever be met using human donors. Even with the government-driven push to increase the donation rate in Australia, many patients will become too sick to receive a transplant or will die while on the waiting list. 

Some scientists believe that stem cells will ultimately provide a solution to this pressing medical problem, but growing a highly complex organ from stem cells remains in the realms of science fiction, at least for now. 

A treatment that is much closer to reality, and indeed has already entered early clinical trials, is the transplantation of animal organs, tissues or cells into humans. This is called xenotransplantation. 

Which species? 

Humans are primates, so the obvious choice of donor animal for xenotransplantation would appear to be another member of the primate family (chimpanzees and baboons, for instance) because of their physiological similarity. But non-human primates have been ruled out as donors for several compelling practical and ethical reasons. 

One of the risks to transplant recipients is infection by viruses transmitted by the transplanted organ. As our closest cousins in the animal kingdom, primates are more likely than other animals to carry viruses capable of infecting humans; HIV, the virus responsible for AIDS, originated in chimpanzees. 

This “relatedness” also poses ethical problems, with the public understandably reluctant to exploit animals that share many features with humans. And even if you discount the ethical question, it’s hard to imagine being able to breed enough primates to meet the increasing demand for donor organs. 

Primates aren't the best fit to donate organs and tissues to humans [Credit: Troy B Thompson]

Pigs, on the other hand, tick many of the boxes. They can be raised in a clean environment, so the risk of infection from pig donors may actually be lower than that from human donors. They are already widely bred for the food industry, solving the supply issue and, provided they are treated humanely, present less of an ethical dilemma. 

Material from pigs has been routinely and safely used for medical purposes for decades, with heart valves the best known example. The evidence from animal models suggests that most pig organs will work properly in human recipients. 

On the downside, the evolutionary distance between pigs and humans means that the human immune system mounts a very strong response to pig organs. The drugs that are used to prevent rejection of human transplants are simply not powerful enough when it comes to pig transplants. 

One solution for this problem is to genetically modify pigs so that their organs will not be recognised as foreign when transplanted into humans. Several groups around the world, including in Australia, have produced GM pigs for xenotransplantation research. These pigs are still in the testing phase, but the progress that has been made over the last 10 years suggests that the move to the clinic is not too far away. 

Treating diabetes with pig islets 

Pigs may also be the key to future treatment of diabetes. Insulin, the hormone that controls the level of sugar in the blood, is made by clusters of cells in the pancreas called islets. People with type 1 diabetes have abnormally high blood sugar because their islets are destroyed by the immune system. While regular insulin injections restore some control, the long term prospects are poor, with complications including renal failure and blindness. 

Transplantation with human islets is an option open to only a handful of patients. Pig islets are an attractive alternative, because pig insulin is 98% identical to human insulin and was used to treat patients before recombinant human insulin became available. 

In a clinical trial currently taking place in New Zealand, pig islets contained within microcapsules have been injected into the abdomen of 11 patients with diabetes. The microcapsules allow nutrients to get in and insulin to get out, but importantly they also protect the pig islets from the recipient’s immune system so that no anti-rejection drugs are needed. Early results suggest that the microcapsule treatment will not be a complete cure, but may benefit patients with severe diabetes. 

In the meantime, many other strategies are being explored. Results from animal models showing islets from GM pigs can reverse diabetes for many months are particularly encouraging. 

Future xenotransplantation 

A recent review in the prestigious medical journal The Lancet is carefully optimistic that clinical xenotransplantation may soon become a reality, particularly for cellular grafts such as islets. Will this be, as suggested by the authors of the review, the “next medical revolution”? We’ll have to wait and see. 

Author: Peter Cowan | Source: The Conversation [December 14, 2011]

Read more »

How We Decide

Until now, most psychology and neural imaging research have focused on how humans learn behavior through trial and error. 

However, Carnegie Mellon University neuroscientists Matthew M. Walsh and John R. Anderson have found that this view is incomplete. 

In their study published in the Proceedings of the National Academy of Sciences (PNAS), Walsh and Anderson show how the brain uses both instruction and experience to select actions. 

This identification of separate neural systems that control behavior also suggests that damage to one may not impair the other. 

"With most decisions that we make, we have access to both experience and instruction sources of information, so it is overly simplistic to just consider one," said Walsh, a doctoral student in the Department of Psychology within CMU's Dietrich College of Humanities and Social Sciences. 

"By tapping different neural learning systems, we can facilitate learning in patient populations. For example, Parkinson's disease is associated with a loss of dopamine and an impaired ability to learn from experience. Consequently, Parkinson's patients may more readily learn from instruction than experience." 

For the study, Walsh and Anderson used electroencephalography (EEG) to measure participants' neural activity during experiments designed to explore how instruction influences trial and error learning.   

The participants were shown two symbols that were assigned different reward values. Their goal was to maximize their reward by selecting the symbol that was more likely to be rewarded within each pair. 

One group received a description of the rewards before choosing, while the other group only received feedback about whether their choices were rewarded. 

The results showed that participants who did not receive instruction gradually learned from experience. Participants who did receive instruction performed perfectly from the beginning. 

Walsh and Anderson focused their analyses on the feedback-related negativity (FRN), a neural signal of reward learning. 

In striking contrast to their behavior, the FRN only developed once participants experienced outcomes in both conditions of the experiment. Thus, while instruction governed behavior, experience controlled the FRN. 

"Little research to this point has looked at how instruction engages behavior," said Walsh. 

"Our work shows that different systems in the brain control behavior, and that one system may learn from experience while the other controls responses." 

Anderson, the R.K. Mellon University Professor of Psychology and Computer Science, has spent the past three decades combining cognitive psychology research with computer science to understand how the brain works, how people learn and how computer-based instructional systems can be used as educational aids. 

For his trailblazing contributions, he received the 2011 Benjamin Franklin Medal in Computer and Cognitive Science. 

"These results highlight a striking dissociation between behavioral and neural responses. While instruction may immediately control behavior, certain neural responses must be learned from experience. Although some theories anticipate such a dissociation, this is the most direct evidence to date," said Anderson. 

Source: Carnegie Mellon University [December 12, 2011]

Read more »