Category: Relationships

Scientists have discovered that the amygdala, a small almond shaped structure deep within the temporal lobe, is important to a rich and varied social life among humans. The finding was published this week in a new study in Nature Neuroscience and is similar to previous findings in other primate species, which compared the size and complexity of social groups across those species.

"We know that primates who live in larger social groups have a larger amygdala, even when controlling for overall brain size and body size," says Lisa Feldman Barrett, PhD, of the Massachusetts General Hospital (MGH) Psychiatric Neuroimaging Research Program and a Distinguished Professor of Psychology at Northeastern University, who led the study. "We considered a single primate species, humans, and found that the amygdala volume positively correlated with the size and complexity of social networks in adult humans."

The researchers also performed an exploratory analysis of all the subcortical structures within the brain and found no compelling evidence of a similar relationship between any other subcortical structure and the social life of humans. The volume of the amygdala was not related to other social variables in the life of humans such as life support or social satisfaction.

"This link between amygdala size and social network size and complexity was observed for both older and younger individuals and for both men and women," says Bradford C. Dickerson, MD, of the MGH Department of Neurology and the Martinos Center for Biomedical Research. "This link was specific to the amygdala, because social network size and complexity were not associated with the size of other brain structures." Dickerson is an associate professor of Neurology at Harvard Medical School, and co-led the study with Dr. Barrett.

The researchers asked 58 participants to report information about the size and the complexity of their social networks by completing standard questionnaires that measured the total number of regular social contacts that each participant maintained, as well the number of different groups to which these contacts belonged. Participants, ranging in age from 19 to 83 years, also received a magnetic resonance imaging brain scan to gather information about the structure of various brain structures, including the volume of the amygdala.

A member of the the Martinos Center at MGH, Barrett also notes that the results of the study were consistent with the "social brain hypothesis," which suggests that the human amygdala might have evolved partially to deal with an increasingly complex social life. "Further research is in progress to try to understand more about how the amygdala and other brain regions are involved in social behavior in humans," she says. "We and other researchers are also trying to understand how abnormalities in these brain regions may impair social behavior in neurologic and psychiatric disorders."

Co-Authors of the Nature Neuroscience paper are Kevin C. Bickart, Boston University School of Medicine; and Christopher I. Wright, MD, PhD, and Rebecca J. Dautoff of the MGH Psychiatric Neuroimaging Research Program and the Martinos Center. The study was supported by grants from the US National Institutes of Health and the US National Institute on Aging.

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Journal Reference:

1. Kevin C Bickart, Christopher I Wright, Rebecca J Dautoff, Bradford C Dickerson, Lisa Feldman Barrett. Amygdala volume and social network size in humans. Nature Neuroscience, 2010; DOI: 10.1038/nn.2724

The accent someone talks in plays a crucial role in the way we judge this person, psychologists of the Friedrich Schiller University Jena (Germany) found out recently.

"The accent is much more important than the way a person looks," Dr. Tamara Rakic sums up one of the key findings of the study, which has just been published in the online edition of the Journal of Personality and Social Psychology. The study is based on the PhD thesis of Dr. Rakic in the International Graduate College entitled "Conflict and Cooperation between Social groups."

"The classification into social categories, like for instance ethnicity, happens spontaneously and helps us to understand and simplify the complex world and to enable us to deal more easily with complexity," Dr. Rakic says. However the psychologist continues, categorizing can turn into unreflected stereotype-based judgment and lead to discrimination. The psychologists from the Jena University investigate the process of person perception in a project, lead by Professor Dr. Melanie Steffens, within the research unit "Person Perception."

In their current studies Dr. Rakic and her colleagues Professor Dr. Melanie Steffens and Professor Dr. Amélie Mummendey tested empirically for the first time the influence of language on ethnic categorization. "With our language we are not only transmitting information. Language itself provides a lot of information about the person speaking," Dr. Rakic says. According to Dr. Rakic one can draw conclusions from the language about the temperament, age or state of mind of a person. "Those who have an accent give away their ethnic background as well."

Previously scientists assumed that visual cues have a priority in categorizing unknown people. "The great majority of studies focused on the looks," the Jena psychologist Rakic says. In contrast the influence of the language — or more precisely of the accent — has been neglected so far. Wrongly, as the Jena scientists could demonstrate now.

They showed to the participants the photos of German and Italian looking persons together with a written statement of the persons depicted. Then the participants had to assign the statements to the depicted persons. In accordance with earlier findings mix-ups were particularly common within the groups of German and Italian looking persons. Statements made by German looking persons however were not wrongly assigned to Italian looking persons (or vice versa). But it got more interesting when accents were added: Now some German looking persons spoke standard German and some with an Italian accent, (as well as Italian looking people).

"The results indicate that the participants orientated themselves nearly exclusively on the spoken accent while categorizing people," Dr. Rakic summarizes her results. The looks which came into the equation by categorizing in the first experiment while no other information was provided were not important anymore. According to Rakic this is proof of the great importance of language as a source of information in the ethnic categorization: this is in accordance with the assumption that accent free language plays a crucial role in social integration.

Journal Reference:

1. Tamara Rakić, Melanie C. Steffens, Amélie Mummendey. Blinded by the accent! The minor role of looks in ethnic categorization. Journal of Personality and Social Psychology, 2010; DOI: 10.1037/a0021522

Friendless kids can become social outcasts who risk spiraling into depression by adolescence, according to new research from Concordia University, Florida Atlantic University and the University of Vermont. Yet for most shy and withdrawn children, the study reports in the journal Development and Psychopathology, friends can be a form of protection against sadness.

"The long-term effects of being a withdrawn child are enduringly negative," says lead author William M. Bukowski, a psychology professor and director of the Concordia Centre for Research in Human Development. "Over time, we found that withdrawn kids showed increasing levels of sadness and higher levels of depressive feelings."

A total of 130 girls and 101 boys in the third through fifth school grades, took part in the three-year study. Participants were asked to rate whether they felt shy or preferred solitude. The research team also found that peers typically excluded children with poor social skills, who were perceived as overly aggressive or immature.

Compared with friendless children, those who had friends were less likely to report depressed feelings. "Friendship disrupts the negative and long-term effects of withdrawal," says Dr. Bukowski, who is also Concordia University Research Chair in Psychology. "Friendship promotes resilience and protects at-risk kids from internalizing problems such as feeling depressed and anxious."

Withdrawal can have consequences that extend beyond the near term. "In much the same was as a snowball rapidly grows as it rolls down a hill, an adjustment problem is thought to amplify as it worsens," says Dr. Bukowski. "Being isolated and excluded from the peer group can increase levels of depressed feelings in children and those negative feelings can escalate throughout adolescence."

The key to avoid peer rejection is to make at least one friend. "Having one friend can be protective for withdrawn or shy kids," says Dr. Bukowski. "Our study confirms the value of having friends, which are like a shield against negative social experiences."

This study was funded by the Social Sciences and Humanities Research Council of Canada, the W. T. Grant Foundation, the National Institute of Mental Health and the National Science Foundation.

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Journal Reference:

1. William M. Bukowski, Brett Laursen, Betsy Hoza. The snowball effect: Friendship moderates escalations in depressed affect among avoidant and excluded children. Development and Psychopathology, 2010; 22 (04): 749 DOI: 10.1017/S095457941000043X

 A study of long-term, active duty military personnel who used Department of Veterans Affairs' health services showed that childhood maltreatment and other high magnitude stressors, such as being in a serious accident or a natural disaster, were more strongly associated with participants' current psychiatric symptoms than were their military sexual experiences, such as sexual harassment.

The research, described in the Journal of Psychiatric Research, was completed by Dr. Maureen Murdoch and colleagues of the Minneapolis VA Health Care System and University of Minnesota Schools of Medicine and Public Health in collaboration with researchers from Illinois State University, Normal, IL; North Florida/South Georgia Veterans Health System, Gainesville, FL; and Analytic Services, Inc., Arlington, VA. 

The researchers conducted a mailed survey of 681 confirmed active duty troops registered in the VA's Enrollment Database between 2001 and 2003. Eighty-four percent of contacted troops responded.

Most prior research examining associations between military sexual stressors and psychiatric symptoms has not accounted for participants' other stressor experiences and consequently may have over- or under-estimated the association between military sexual stressors and psychiatric symptoms.

By evaluating troops' stressor experiences more comprehensively, the researchers discovered that many stressors are interrelated. For example, troops who experienced childhood maltreatment were also more likely than other participants to report military sexual stressor experiences, and they were more likely to report other high magnitude stressors.

Working in a military unit seen as tolerating sexual harassment was also associated with reporting more types of military sexual stressors and with reporting more psychiatric symptoms. Findings remained the same when men and women were analyzed separately. The researchers speculated that learning how and why childhood maltreatment increases troops' odds of experiencing military sexual stressors might lead to interventions to reduce the latter.

"Eradicating tolerance for military sexual harassment might also reduce troops' risk of experiencing military sexual stressors and reduce psychiatric symptoms," Dr. Murdoch said.

The researchers studied a unique sample of military personnel, and members of the Marine Corps were especially underrepresented. Therefore, the researchers cautioned that the results may not pertain to the Marine Corps or to the military as a whole. The researchers urged that additional studies be done in other military populations to see if their findings could be replicated.

The research was funded by the Department of Veterans Affairs Health Services Research and Development Service.

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Journal Reference:

1. Maureen Murdoch, John B. Pryor, Melissa A. Polusny, Melanie M. Wall, Diane Cowper Ripley, Gary Dean Gackstetter. The association between military sexual stress and psychiatric symptoms after controlling for other stressors. Journal of Psychiatric Research, 2010; 44 (16): 1129 DOI: 10.1016/j.jpsychires.2010.09.009