A problem shared is a problem halved

 The experience of being bullied is particularly detrimental to the psychological health of school girls who don't have social support from either adults or peers, according to a new study by Dr. Martin Guhn and colleagues from the University of British Columbia in Canada. In contrast, social support from adults or peers (or both) appears to lessen the negative consequences of bullying in this group, namely anxiety and depression.

The work is published online in Springer's Journal of Happiness Studies.

Guhn and his team looked at whether the combination of high levels of bullying and low levels of adult as well as peer support have a multiplicative negative effect on children's well-being.

A total of 3,026 ten-year-old school children from 72 schools in Vancouver, Canada, took part in the study and completed questionnaires, which assessed their satisfaction with life, their self-esteem, and their levels of anxiety and depression. The authors looked at whether the ratings for these factors differed, according to the quality of the children's relationships with both adults and their peers and how often they felt victimized.

Overall, girls were more likely to report positive relationships with both adults and peers, higher satisfaction with life, higher self-esteem as well as higher anxiety levels. There were no differences between boys' and girls' reported levels of bullying and depression. However, as many as 1 in 7 girls and 1 in 6 boys felt victimized several times a week, with verbal and social victimization more commonly reported than physical bullying; cyber bullying appeared to be relatively low.

The authors also found that positive relationships with adults and peers were strongly linked to life satisfaction and self-esteem, whereas bullying was strongly linked to depressive symptoms and anxiety. In addition, victimization was particularly strongly linked to low life satisfaction, low self-esteem and more depressive symptoms in girls who reported low levels of social support from adults as well as from peers.

The authors conclude: "Our findings have implications for promoting children's well-being in school and community contexts, supporting interventions that foster relationship-building skills and simultaneously reduce victimization. In other words, children need more than the absence of risk factors to experience good mental health and well-being."


Journal Reference:

  1. Martin Guhn, Kim A. Schonert-Reichl, Anne M. Gadermann, Shelley Hymel, Clyde Hertzman. A Population Study of Victimization, Relationships, and Well-Being in Middle Childhood. Journal of Happiness Studies, 2012; DOI: 10.1007/s10902-012-9393-8

Child-free women feel intense pressure to have kids, but rarely stress over it

Women who choose to be permanently childfree perceive more social pressures to become mothers than other women, but feel less distress about not having kids than women who are childless from infertility or other reasons, a new national study shows.

The study, from a national survey of nearly 1,200 American women of reproductive age with no children, identified various reasons why women have no children, from medical and situational barriers to delaying pregnancy to choosing to be childfree. It sought to determine if those reasons contributed to different types of concerns about being childless.

"Motherhood is so highly connected with adult femininity in the United States that many women feel that they need to be mothers," said Julia McQuillan, a University of Nebraska-Lincoln sociologist and the study's lead author. "Yet we also found that there are women who have low or no distress about not being mothers, even if their friends and family want them to have children."

In recent years more U.S. women — estimates suggest about 20 percent — are ending childbearing years without having children. Some can't conceive because of biomedical infertility; others simply delay because of financial concerns, educational demands, job demands, not finding the right partner or other situational barriers. Though all the women were in the same social situation — not being mothers — researchers questioned if the specific reason for not having children shaped how they experienced their situation.

The study found that the reason for having children did matter for distress related to not having children, but only because reasons were associated with how important motherhood is to women's identities. Women who were involuntarily childless because of biomedical reasons put the highest importance on motherhood, and had the highest distress.

Researchers were surprised that pressure from others was not a bigger factor in explaining differences in distress, since many American women face social pressures to have children. But the study showed that influence from others to have children was associated with distress only if the women considered motherhood important. That key factor overrode many others — social pressures, income, age, race and education level — as the most important attribute in judging childlessness concerns.

The results of the study, the first to closely examine the different reasons behind childlessness and their social effects on women, raise questions about what room there is in American culture for women to have successful, fulfilling lives without being mothers, McQuillan said.

"This highlights that not all women without children are the same. While some may be devastated, others are content and finding fulfillment through other avenues such as leisure or career pursuits," she said. "Rather than assume that women without children are missing something, society should benefit from valuing a variety of paths for adult women to have satisfying lives."

Also in the study:

  • The proportion of Hispanic and African-American women was lowest among those who were voluntarily childfree, but was highest among women with biomedical fertility barriers. That pattern was the opposite for white women.
  • The average age of voluntarily childfree women was about four years older than the average age among childless women with biomedical barriers, and about six years older than childless women with or without situational barriers.
  • Family income was highest among voluntarily childfree women and lowest among women with medical barriers.
  • Women who considered themselves more religious actually perceived fewer average social messages stressing the importance of having children, compared with less religious women.

"Listening to a broad spectrum of American women about the degree of importance of motherhood in their lives and the meanings of not having children is reshaping how we think about opportunities for meaningful adult femininity," McQuillan said. "Just as reproductive options have increased, both for limiting fertility and overcoming fertility barriers, we are learning what is devastating for some women is a relief for other women."

Online attitudes predict individuals' compulsive and excessive Internet use and poor well-being

Researchers are exploring how specific online communication attitudes — such as individuals' tendency for online self-disclosure, online social connection, and online anxiety — predicted their compulsive and excessive Internet use and, in turn, low sense of well-being.

Among the most popular questions addressed in online communication research is the extent to which Internet use leads to undesirable psychosocial outcomes such as depression and loneliness. Evidence suggests that certain motivations to communicate online can have negative consequences, as the Internet itself can, for some, serve as an object of compulsive use. Individuals' compulsive Internet use (CIU) refers to their inability to control, reduce, or stop their online behavior, while excessive Internet use (EIU) is the degree to which an individual feels that he or she spends an excessive amount of time online or even loses track of time when using the Internet. For those who are unable to limit their use, time spent online may produce negative outcomes such as depression, loneliness, and limited face-to-face contacts.

Mazer and Andrew M. Ledbetter (Texas Christian University) have an article published October 9 in Southern Communication Journal that explores how specific online communication attitudes — such as individuals' tendency for online self-disclosure, online social connection, and online anxiety — predicted their compulsive and excessive Internet use and, in turn, poor well-being.

Mazer and Ledbetter found that an individual's tendency for online self disclosure and online social connection led them to use the Internet in more compulsive ways. If a person has poor face-to-face communication skills that individual will likely be more attracted to the social features of online communication, which can foster CIU.

Prior research suggests that socially anxious individuals perceive online communication environments as less threatening and, as a result, are more likely to seek out communication in those settings. The findings from Mazer and Ledbetter's study are not entirely consistent with this claim, which may suggest that researchers adjust their theoretical image of the compulsive user: Whereas previous research frames online communication as a safe activity for the socially anxious to escape their communication anxiety, Mazer and Ledbetter found that compulsive users also experience anxiety when communicating online.

To the extent that socially anxious individuals are drawn to the Internet, such anxiety seems to stimulate compulsive, but not necessarily excessive, use. Rather, excessive users seem to have a more realistic perception of online communication as convenient but sometimes limited in communicative effectiveness by a lack of social cues often available in face-to-face interactions. In other words, according to Mazer and Ledbetter's study, individuals' anxiety motivates CIU, while efficiency seems to motivate EIU.

Mazer and Ledbetter found that CIU, not EIU, led individuals' to experience poor well-being outcomes. Given their widespread proliferation and adoption, especially among younger users, social networking sites now represent an important medium for maintaining social connections. Their existence raises important questions regarding individual traits that might influence online communication frequency and how excessive participation in these sites might foster compulsive and excessive Internet use.


Journal Reference:

  1. Joseph P. Mazer, Andrew M. Ledbetter. Online Communication Attitudes as Predictors of Problematic Internet Use and Well-Being Outcomes. Southern Communication Journal, 2012; 77 (5): 403 DOI: 10.1080/1041794X.2012.686558

Flirting can pay off for women, study finds

When Madeleine Albright became the first female U.S. Secretary of State, she led high-level negotiations between mostly male foreign government leaders. In 2009, comedian Bill Maher asked Albright if she ever flirted on the job and she replied, "I did, I did." Flirtatiousness, female friendliness, or the more diplomatic description "feminine charm" is an effective way for women to gain negotiating mileage, according to a new study by Haas School of Business Professor Laura Kray.

"Women are uniquely confronted with a tradeoff in terms of being perceived as strong versus warm. Using feminine charm in negotiation is a technique that combines both," says Kray, who holds the Warren E. and Carol Spieker Chair in Leadership at the Haas School.

The study, "Feminine Charm: An Experimental Analysis of its Costs and Benefits in Negotiations," was published in October in the journal Personality and Social Psychology Bulletin and co-authored by Haas PhD alumna Connson C. Locke of the London School of Economics and Haas PhD candidate Alex B. Van Zant.

Flirtation that generates positive results, says Kray, is not overt sexual advances but authentic, engaging behavior without serious intent. In fact, the study found female flirtation signals attractive qualities such as confidence, which is considered essential to successful negotiators.

To determine whether women who flirt are more effective in negotiating than men who flirt, the researchers asked 100 participants to evaluate to what extent they use social charm in negotiation on a one-to-seven scale.

Earlier that week, the participants evaluated their partners' negotiating effectiveness. Women who said they used more social charm were rated more effective by their partners. However, men who said they used more social charm were not regarded as more effective.

In the second experiment, the researchers asked subjects to imagine they were selling a car worth $1,200 and asked for how much would they sell the car. Next, the subjects read one of two scenarios about a potential buyer named Sue. The first group meets Sue, who shakes hands when she meets the seller, smiles, and says, "It's a pleasure to meet you,." and then "What's your best price?" in a serious tone. The second group reads an alternate scenario in which Sue greets the seller by smiling warmly, looking the seller up and down, touching the seller's arm, and saying, "You're even more charming than over email," followed by a playful wink and asking, "What's your best price?"

The result? Male sellers were willing to give the "playful Sue" more than $100 off the selling price whereas they weren't as willing to negotiate with the "serious Sue." Playful Sue's behavior did not affect female car sellers.

Kray says many of her students who are senior women executives admit they love to flirt and describe themselves as "big flirts." Kray maintains flirting is not unprofessional if it remains playful and friendly.

"The key is to flirt with your own natural personality in mind. Be authentic. Have fun. That will translate into confidence, which is a strong predictor of negotiation performance."


Journal Reference:

  1. L. J. Kray, C. C. Locke, A. B. Van Zant. Feminine Charm: An Experimental Analysis of its Costs and Benefits in Negotiations. Personality and Social Psychology Bulletin, 2012; 38 (10): 1343 DOI: 10.1177/0146167212453074

Developing brain is source of stability and instabilty in adolescence

 Scientists are presenting new research on how the brain develops during the dynamic and vulnerable transition period from childhood to adulthood. The findings underscore the uniqueness of adolescence, revealing factors that may influence depression, decision-making, learning, and social relationships.

The findings were presented at Neuroscience 2012, the annual meeting of the Society for Neuroscience and the world's largest source of emerging news about brain science and health.

The brain's "reward system," those brain circuits and structures that mediate the experience and pursuit of pleasure, figured prominently in several studies. The studies shed light on adolescents' ability to control impulsivity and think through problems; reveal physical changes in the "social brain;" document connections between early home life and brain function in adolescence; and examine the impact of diet on depressive-like behavior in rodents.

Today's new findings show that:

  • Adolescents can throw impulsivity out the window when big rewards are at stake. The bigger the reward, the more thoughtful they can be, calling on important brain regions to gather and weigh evidence, and make decisions that maximize gains (BJ Casey, PhD, abstract 128.04).
  • Rodents that receive an omega-3 fatty acid in their diets, from gestation through their early development, appear less vulnerable to depressive-like behaviors during adolescence (Christopher Butt, PhD, abstract 522.07).
  • Depression in older adolescent boys may be associated with changes in communication between regions of the brain that process reward. At the same time, the study found possible connections between early emotional attachments — particularly with mothers — and later reward system function (Erika Forbes, PhD, abstract 128.11).
  • Early cognitive stimulation appears to predict the thickness of parts of the human cortex in adolescence, and experiences at age four appear to have a greater impact than those at age eight (Martha Farah, PhD, abstract 908.02).
  • During the span of adolescence, the volume of the "social brain" — those areas that deal with understanding other people — changes substantially, with notable gender differences (Kathryn Mills, BA, abstract 128.02).

"Advances in neuroscience continue to delve deeper and deeper into the unique and dynamically changing biology of the adolescent brain," said press conference moderator Jay Giedd, MD, of the National Institute of Mental Health, an expert on childhood and adolescent brain development. "The insights are beginning to elucidate the mechanisms that make the teen years a time of particular vulnerabilities but also a time of great opportunity."

This research was supported by national funding agencies such as the National Institutes of Health, as well as private and philanthropic organizations.

New research reveals more about how the brain processes facial expressions and emotions

Research is helping reveal how human and primate brains process and interpret facial expressions, and the role of facial mimicry in everything from deciphering an unclear smile to establishing relationships of power and status.

The findings were presented at Neuroscience 2012, the annual meeting of the Society for Neuroscience and the world's largest source of emerging news about brain science and health.

Facial mimicry — a social behavior in which the observer automatically activates the same facial muscles as the person she is imitating — plays a role in learning, understanding, and rapport. Mimicry can activate muscles that control both smiles and frowns, and evoke their corresponding emotions, positive and negative. The studies reveal new roles of facial mimicry and some of its underlying brain circuitry.

Today's new findings show that:

  • Special brains cells dubbed "eye cells" activate in the amygdala of a monkey looking into the eyes of another monkey, even as the monkey mimics the expressions of its counterpart (Katalin Gothard, MD, PhD, abstract 402.02).
  • Social status and self-perceptions of power affect facial mimicry, such that powerful individuals suppress their smile mimicry towards other high-status people, while powerless individuals mimic everyone's smile (Evan Carr, BS, abstract 402.11).
  • Brain imaging studies in monkeys have revealed the specific roles of different regions of the brain in understanding facial identity and emotional expression, including one brain region previously identified for its role in vocal processing (Shih-pi Ku, PhD, abstract 263.22).
  • Subconscious facial mimicry plays a strong role in interpreting the meaning of ambiguous smiles (Sebastian Korb, PhD, abstract 402.23).

Another recent finding discussed shows that:

  • Early difficulties in interactions between parents and infants with cleft lip appear to have a neurological basis, as change in a baby's facial structure can disrupt the way adult brains react to a child (Christine Parsons, PhD).

"Today's findings highlight the role of facial expressions in communication and social behavior," said press conference moderator Martha Farah, PhD, of the University of Pennsylvania, an expert on brain development and poverty. "Brain circuits that interpret the face appear ever more specialized, from primate 'eye cells,' to brain feedback that enables us to discern meaning through facial mimicry."

This research was supported by national funding agencies, such as the National Institutes of Health, as well as private and philanthropic organizations.

Parental bonding makes for happy, stable child

Parents: Want to help ensure your children turn out to be happy and socially well adjusted? Bond with them when they are infants.

That's the message from a study by the University of Iowa, which found that infants who have a close, intimate relationship with a parent are less likely to be troubled, aggressive or experience other emotional and behavioral problems when they reach school age. Surprisingly, the researchers found that a young child needs to feel particularly secure with only one parent to reap the benefits of stable emotions and behavior, and that being attached to dad is just as helpful as being close to mom.

The study bolsters the still-debated role of the influence that a parent can exercise at the earliest stages in a child's mental and emotional development, the authors contend in the paper, published in the journal Child Development.

"There is a really important period when a mother or a father should form a secure relationship with their child, and that is during the first two years of life. That period appears to be critical to the child's social and emotional development," says Sanghag Kim, a post-doctoral researcher in psychology at the UI who collaborated with UI psychology professor Grazyna Kochanska on the study. "At least one parent should make that investment."

The researchers assessed the relationship of 102 infants (15 months old) with a parent and then followed up with 86 of them when they reached age 8. Separate surveys of the parents and the child were taken at that time. The infants and parents were drawn from a broad spectrum of income, education, and race. All the couples were heterosexual.

The authors also solicited feedback from teachers about the children, which ranged from concerns about inner emotions, such as worry or sadness, to more outward displays, such as disobedience and aggression. Interestingly, the children's reports and their teachers' impressions were similar; yet they differed, sometimes greatly, from the parents' evaluations.

"Parents and teachers have different perspectives," Kim explains. "They observe children in different contexts and circumstances. That is why we collected data from many informants who know the child."

The researchers were surprised to find out that infants who had felt attached to both parents did not enjoy additional mental and emotional advantages into childhood, compared to those who had been close to one parent. The UI psychologists' best explanation is that a warm, secure, and positive bond with at least one primary caregiver may be enough to meet the child's need for security and to provide a solid foundation for development. Other studies have contended that being secure with both parents can have additional advantages; this study, however, checked in with the children when they were older and their outcomes could be more fully measured than those surveyed in previous work, the Iowa researchers said.

The study appears to be good news for single mothers and stay-at-home dads, two marked parenting shifts that are defining this generation. Kim says the study shows that either parent can serve as a secure, attachment figure for the infant, thus providing the closeness and support to promote the child's healthy emotional growth.

"Some people think the father is not good enough to be the primary caregiver," says Kim, who earned his doctorate in sociology at the UI last year. "Our data show otherwise."

The study did not directly sample single mothers, as all families included two parents. Still, the finding that one parent can provide the tight bond and emotional dividends as two parents "is a good sign," Kim says, that should be studied further.

On the other end, the study showed that infants who had not felt secure with either parent were more likely to report worries, fears, and aggression when they reached school age. While the trend was clear, the Iowa researchers said, they cautioned that other reasons may explain those children's difficulties. Also, they note, that all children fell into what psychologists would consider a normal development range, largely without clinically significant problems.

Kochanska, the paper's corresponding author, says the study was inspired by the attachment theory, a key approach in the field of social and emotional development. She and colleagues have conducted several studies examining the long-term implications of a child's early relationship with the parents.

Some questions need further study. Among them is whether day-care providers can serve as effective care givers, providing emotional support for infants, or whether they interfere with an infant's ability to bond with the parents.


Journal Reference:

  1. Grazyna Kochanska, Sanghag Kim. Early Attachment Organization With Both Parents and Future Behavior Problems: From Infancy to Middle Childhood. Child Development, 2012; DOI: 10.1111/j.1467-8624.2012.01852.x

Testosterone increases honesty, study suggests

 Testosterone is considered THE male hormone, standing for aggression and posturing. Researchers working with Dr. Armin Falk, an economist from the University of Bonn, have now demonstrated that this sex hormone surprisingly also fosters social behavior. In play situations, subjects who had received testosterone clearly lied less frequently than individuals who had only received a placebo.

The results have just been published in the Public Library of Science's international online journal PLoS ONE.

The hormone testosterone stands for typically male attributes — it fosters the forming of the sexual characteristics, increases libido and muscle building. Women also have this sex hormone, but to a much lesser extent. "Testosterone has always been said to promote aggressive and risky behavior and posturing," reports Prof. Dr. Bernd Weber, a neuro-scientist from the Center for Economics and Neuroscience (CENS) at the University of Bonn. More recent studies indicate, however, that this sex hormone also fosters social behavior.

Cause-and-effect issues remains unresolved

"The disadvantage of many studies is, however, that they only correlate their subjects' testosterone level with their behavior," explains lead author Dr. Matthias Wibral, adding that this approach only reflects statistical links while not providing any insights into the causes for the behavior. "For testosterone does not only influence behavior; behavior, in turn, also influences hormone levels." Consequently, the CENS scientists were looking for an experimental approach that would also allow deducing cause and effect.

Bonn researchers using new approach

The scientists recruited a total of 91 healthy men for a behavioral experiment. Out of this group of subjects, 46 were treated with testosterone by applying it to the skin in gel form. On the following day, endocrinologists from the Bonn University Hospitals checked whether the blood testosterone levels were indeed higher in these subjects than in the placebo group. The other 45 test subjects only received a placebo gel. "Neither the subjects themselves nor the scientists performing the study knew who had received testosterone and who hadn't," reports Dr. Wibral. This was done to prevent behaviors from potentially being affected.

Games of dice with cheating option

This was followed by the behavioral experiments. The test subjects played a simple game of dice in separate booths. The higher their scores, the higher the amounts of money they received as a reward. "These experiments were designed such that the test subjects were able to lie," reports Prof. Weber. "Due to the separate booths, nobody knew whether they were entering their real scores into the computer, or higher ones in order to get more money." However, the scientists were able to determine later whether the various test subjects had cheated or not. "Statistically, the probability for all numbers on the dice to occur is identical," explains the neuroscientist. "So, if there are outliers in the higher numbers, this is a clear indication that subjects have been cheating."

Test subjects with higher testosterone levels lied less

The researchers compared the results from the testosterone group to those from the control group. "This showed that the test subjects with the higher testosterone levels had clearly lied less frequently than untreated test subjects," reports the economist Prof. Dr. Armin Falk, who is one of the CENS co-directors with Prof. Weber. "This result clearly contradicts the one-dimensional approach that testosterone results in anti-social behavior." He added that it is likely that the hormone increases pride and the need to develop a positive self-image. "Against this background, a few euros are obviously not a sufficient incentive to jeopardize one's feeling of self-worth," Prof. Falk reckons.

Lies are widespread in personal life and business

Great taboos are attached to the phenomenon of lying. The Christian 8th Commandment, e.g., forbids "bearing false witness." Prof. Falk says, "However, lies play a great part both in the business world as well as in personal life." He adds that people frequently do not just lie to their own advantage, but also in order to protect or benefit others. This type of behavior and its economic effects had been studied often. "However, there are very few studies on the biological causes of lying," the Bonn economist explains. "In this regard, this study has allowed us to make a big step forward."


Journal Reference:

  1. Wibral M, Dohmen T, Klingmüller D, Weber B, Falk A. Testosterone Administration Reduces Lying in Men. PLoS ONE, 2012 DOI: 10.1371/journal.pone.0046774

Immune response may link social rejection to later health outcomes

No matter which way you look at it, rejection hurts. Experiencing rejection from a boss, a friend, or a partner is difficult enough for many adults to handle. But adolescents, who are dealing with the one-two punch of biological and social change, may be the most vulnerable to its negative effects.

In a new study published in Clinical Psychological Science, a journal of the Association for Psychological Science, researcher Michael Murphy and colleagues examine the human immune response as a potential link between social stressors like rejection and later mental and physical health outcomes.

There are many kinds of stressors that increase our risk for disease, but stressors that threaten our social standing, such as targeted rejection, seem to be particularly harmful.

Many people are probably familiar with targeted rejection from their school days, when a student was actively and intentionally rejected by another student or a group of students. It's the kind of behavior that we see in so many cases of ostracism and bullying.

"Targeted rejection is central to some of life's most distressing experiences — things like getting broken up with, getting fired, and being excluded from your peer group at school," said Murphy. "In this study, we aimed to examine processes that may give these experiences the ability to affect health."

Previous research has shown that people who are on the receiving end of this kind of rejection experience symptoms of depression three times faster than people who are faced with similarly severe life events. Researchers believe that certain inflammatory processes that are part of the immune response could be a link between targeted rejection and depression.

Murphy and colleagues decided to directly investigate whether rejection-related life events affect inflammatory activity by conducting a study that followed 147 healthy adolescent women over 2.5 years. The participants did not have a personal history of mental health problems but were all at risk for major depression due to family and other personal risk factors.

The participants were assessed for psychiatric diagnoses, incidences of targeted rejection, perceived social status, expression of inflammatory signaling molecules, and indicators of low-grade inflammation every 6 months over the course of the study.

The data collected suggest that recent exposure to targeted rejection does indeed activate the molecular signaling pathways that regulate inflammation. Participants had elevated levels of pro-inflammatory signaling molecules at visits when they had recently experienced an incidence of targeted rejection compared to visits when no targeted rejection had occurred.

Interestingly, the effect was more pronounced in those who perceived their social status to be higher.

Murphy and colleagues speculate that this inflammatory response might be adaptive for individuals at the top of a social hierarchy, giving them a survival advantage. The researchers note, however, that an overly productive immune response can be harmful to mental and physical health in the long run.

If substantiated in future research, these findings could have implications for understanding how social conditions increase risk for a variety of inflammation-related diseases, including obesity, diabetes, cardiovascular disease, certain types of cancer, and depression.

The study was co-authored by George M. Slavich, University of California, Los Angeles; Nicolas Rohleder, Brandeis University; and Gregory E. Miller, University of British Columbia.

The research was supported by grants from the Canadian Institutes of Health Research, the National Alliance for Research on Schizophrenia and Depression, the Heart and Stroke Foundation of Canada, and the National Institute of Child Health and Human Development.


Journal Reference:

  1. M. L. M. Murphy, G. M. Slavich, N. Rohleder, G. E. Miller. Targeted Rejection Triggers Differential Pro- and Anti-Inflammatory Gene Expression in Adolescents as a Function of Social Status. Clinical Psychological Science, 2012; DOI: 10.1177/2167702612455743

When leaving your wealth to your sister's sons makes sense

— To whom a man's possessions go when he dies is both a matter of cultural norm and evolutionary advantage.

In most human societies, men pass on their worldly goods to their wife's children. But in about 10 percent of societies, men inexplicably transfer their wealth to their sister's sons — what's called "mother's brother-sister's son" inheritance. A new study on this unusual form of matrilineal inheritance by Santa Fe Institute reseacher Laura Fortunato has produced insights into this practice.

Her findings appear October 17 in the online edition of Proceedings of the Royal Society B.

"Matrilineal inheritance is puzzling for anthropologists because it causes tension for a man caught between his sisters and wife," explains Fortunato, who has used game theory to study mother's brother-sister's son inheritance. "From an evolutionary perspective it's also puzzling because you expect an individual to invest in his closest relatives — usually the individual's own children."

For decades research on the practice of matrilineal inheritance focused on the probabilities of a man being the biological father of his wife's children — probabilities that lie on a sliding scale depending on the rate of promiscuity or whether polyandrous marriage (when a woman takes two or more husbands) is practiced.

Of special interest has been the probability value below which man is more closely related to his sister's children than to his wife's children. Below this "paternity threshold" a man is better off investing in his sister's offspring, who are sure to be blood relatives, than his own wife's children.

In her work modeling the evolutionary payoffs of marriage and inheritance strategies, Fortunato looked beyond the paternity threshold to see, among other things, what payoffs there were for men and women in different marital situations — including polygamy.

"What emerges is quite interesting," says Fortunato. "Where inheritance is matrilineal, a man with multiple wives 'wins' over a man with a single wife." That's because wives have brothers, and those brothers will pass on their wealth to the husband's sons. So more wives means more brothers-in-laws to invest in your sons.

The model also shows an effect for women with multiple husbands. The husband of a woman with multiple husbands is unsure of his paternity, so he may be better off investing in his sister's offspring.

"A woman does not benefit from multiple husbands where inheritance is matrilineal, however," Fortunato explains, "because her husbands will invest in their sisters' kids." Family structure determines how societies handle relatedness and reproduction issues, Fortunato says. Understanding these practices and their evolutionary implications is a prerequisite for a theory of human behavior.


Journal Reference:

  1. Dr Laura Fortunato. The evolution of matrilineal kinship organization. Proceedings of the Royal Society B, October 17, 2012 DOI: 10.1098/rspb.2012.1926