Human imaging studies have, for the first time, identified brain circuitry which is believed to be associated with social status. This is according to researchers at the National Institute of Mental Health (NIMH) of the National Institutes of Health.
In their research, they found that different areas of the brain are activated when a person moves up or down in the pecking order of their social scene. The same applied to their views with regards to perceived social superiors or inferiors.
Circuitry activated by important events responded to a potential change in hierarchical status as much as it did to winning money.
"Our position in social hierarchies strongly influences motivation as well as physical and mental health, " said NIMH Director Thomas R Insel, M.D. "This first glimpse into how the brain processes that information advances our understanding of an important factor which can impact public health."
Caroline Zink (Ph.D.), Andreas Meyer-Lindenberg (M.D., Ph.D.) and colleagues of the NIMH Genes Cognition and Psychosis Program, reported on their functional magnetic resonance imaging (fMRI) study in the April 24, 2008, issue of the journal Neuron. Meyer-Lindenberg is now director of Germany’s Central Institute of Mental Health.
Social status psychologically influences one's health
Prior studies have shown that social status has a strong impact on one's health. Animals chronically stressed by their hierarchical position have high rates of cardiovascular and depression/anxiety-like syndromes.
A classic study of British civil servants found that the lower one ranked, the higher the odds for developing cardiovascular disease and dying early.
Lower social rank may then compromise one's health more psychologically, such as by limiting control over one’s life and interactions with others.
However, in hierarchies that allow for more upward movement in status, those at the top who stand to lose their positions may actually have a higher risk for stress-related illness. However, little is known about how the human brain translates such factors into health risk.
How the study was done
To find out, the NIMH researchers created an artificial social hierarchy in which 72 participants played an interactive computer game for money.
They were assigned a status that they were told was based on their playing skill. In fact, the game outcomes were predetermined and the other 'players' which were simulated by computer.
While their brain activity was monitored by fMRI, participants intermittently saw pictures and scores of an inferior and a superior 'player' they thought were simultaneously playing in other rooms.
What was found was that although they knew the perceived players’ scores would not affect their own outcomes or reward, and had been instructed to ignore them, participants’ brain activity and behaviour were highly influenced by their position in the implied hierarchy.
"The processing of hierarchical information seems to be hard-wired, occurring even outside of an explicitly competitive environment, underscoring how important it is for us," said Zink.
Findings may hold key to stress-related health problems
Some of the key findings in the study include:
- The area that signals an event’s importance (called the ventral striatum) responded to the prospect of a rise or fall in rank as much as it did to the monetary reward. This confirmed the high value accorded to social status.
- By merely viewing a superior human 'player' as opposed to a perceived inferior one or a computer, an area near the front of the brain that appears to size people up, was activated, making interpersonal judgments and assessing social status. A circuit involving the mid-front part of the brain that processes the intentions and motives of others and emotion processing areas deep in the brain was also activated when the hierarchy became unstable, allowing for upward and downward movement in status.
- By performing better than the superior 'player' this activated areas higher and toward the front of the brain which control action planning. Conversely, while performing worse than an inferior 'player' then activated areas lower in the brain associated with emotional pain and frustration.
- The more positive the mood experienced by participants while at the top of an unstable hierarchy, the stronger was the activity in the emotional pain circuitry when they viewed an outcome that threatened to move them down in status. In other words, people who felt more joy when they won also felt more pain when they lost.
More studies planned
"Such activation of emotional pain circuitry may underlie a heightened risk for stress-related health problems among competitive individuals," suggested Meyer-Lindenberg.
In collaboration with other NIMH researchers, Zink and colleagues are planning follow-up studies to explore brain activity in response to the experimental social hierarchy in patients with mental illnesses like schizophrenia or autism, which are marked by social and thinking deficits.
The researchers will also be exploring whether particular gene variants might differentially affect brain responses in similar experiments. – (EurekAlert)
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