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Creation Date: 8 Nov 2012 | Review Date: 8 Nov 2012

Group Think: The Science of the Social Brain

Source: Society for Neuroscience

What are the drivers behind human interactions in social situations? How do people behave in groups? Can biological responses and processes provide clues about how people make choices in the financial arena? The growing field of social neuroscience focuses on questions such as these and has made headway in explaining the complex relationship between biology and behavior.  

Baboons grooming
Like humans, savanna baboons suffer from anxiety and stress based on their social standing in the group, which often has adverse health effects.
Photo by T. Adams, photographer, used under Creative Commons license.
Mice without oxytocin (oxytocin knockout mice) fail to recognize the familiar mice, exploring them more than control mice do
Mice normally lose interest in mice they have met before, spending less time sniffing or investigating them. However, mice without oxytocin (oxytocin knockout mice) fail to recognize the familiar mice, exploring them more than control mice do. This implies oxytocin plays a role in social engagement.
Courtesy, with permission: Ferguson, et al. The Journal of Neuroscience, 2001

Understanding how people process social information is an important area of research for social neuroscientists. Brain imaging studies show people respond differently to other members of their own social group than to outsiders. This research supports the importance of social information in how people interact with the world around them. 

Other research indicates social interactions may be rewarding, especially among women. Neuroscientists used functional magnetic resonance imaging (fMRI) to scan women’s brains while they played a collaborative game. When players cooperated, the researchers observed activation in parts of the brain related to reward — the nucleus accumbens, caudate nucleus, ventromedial frontal/orbitofrontal cortex, and the rostral anterior cingulate cortex. Later studies conducted with men had a slightly different result. Their reward pathways were more activated when they had an opportunity to punish players who were cheating. Similar research is examining the benefits and biological underpinnings of the social concepts of generosity, empathy, and social justice both in people and in animals.

The Social Hormone

Brain chemistry plays a role in modifying social behaviors. Researchers found that the hormone oxytocin is important in some social behaviors. Released by the pituitary gland, oxytocin has long been known for its involvement in childbirth and in helping mothers bond with their babies. Its impact on social behaviors, however, has only recently become apparent. 

One study found mice unable to produce oxytocin could no longer recognize mice they had previously encountered. But when oxytocin was injected into the amygdala, the part of the brain responsible for processing this kind of information, the mice’s ability to engage socially was restored. Another study reported children with autism have decreased levels of oxytocin. Although the causes of autism are varied and complex, this suggests oxytocin may play a role. 

Building on this work, other researchers showed oxytocin increased trust in a financial situation. In a game that tested trust, participants who sniffed oxytocin invested more money than those who sniffed an inactive substance. Furthermore, brain imaging studies suggest that even after their trust had been violated, investors who had sniffed oxytocin showed no signs of fear, and they did not decrease their investments. Economic decisions, decisions made by individuals in a social setting, and decisions made by groups are all studied by social neuroscientists. 

Stress in Everyday Life

Neuroscientists also monitor the effects of social constructs, such as socioeconomic status, and chronic stress. Research has shown that living in a state of chronic stress can impair the hippocampus, which is key for learning and memory. Chronic stress also has been linked to an array of diseases, including high blood pressure, hardening of the arteries, and abdominal disorders. 

Studies with savanna baboons are helping researchers better understand social stress. Like people, baboons live in social groups and spend plenty of time interacting. Many of these interactions generate stress, much of it built around competition for social rank.

In general, among baboons in a stable dominance hierarchy, lower ranked animals are more stressed, indicated by increased levels of stress hormones. And while higher ranked baboons are generally more relaxed than those ranked below them, alpha males are the exception — they are markedly more stressed than their peers.

Rank is not the only factor that determines stress levels in baboons. Personality matters as well. Those that are isolated or perceive even benign social activities, such as a rival sleeping nearby, as a threat are more stressed — and less healthy overall.

Social neuroscience studies like these are helping to uncover why we behave the way we do. Although still a relatively new field, social neuroscience is illustrating the inextricable connection between the brain, the mind, interpersonal interactions, and the body.

About the Author

Marilyn Fenichel, freelance writer for the Society for Neuroscience, the American Academy for the Advancement of Science, and the National Science Foundation, among others.
Marilyn Fenichel served as the managing editor of the seventh edition of Brain Facts. She is a seasoned writer and editor and has worked for many organizations, including the National Science Foundation, the National Academies, and the American Association for the Advancement of Science.
Read more about neuroscience core concepts for the U. S. National Science Education Standards.