June 22nd, 2010
05:58 PM ET
By Elizabeth Landau
Some people are more outgoing than shy, or worrisome than carefree. Such personality differences are now being explored biologically in the brain.
A new study in the journal Psychological Science finds that several personality traits are associated with definite brain regions. Scientists from the University of Minnesota, University of Toronto, Yale University, and The Mind Research Network in Albuquerque, New Mexico, collaborated on the study.
Participants were 116 people, half of whom were male, and all between 18 and 40 years old. They were given a personality test and then underwent magnetic resonance imaging.
The researchers found evidence in the brain for four of the "Big Five personality traits": extroversion,
A brain region involved in processing reward information, called the medial orbitofrontal cortex, seemed to be associated with how extroverted participants were. Extroverted people tend to be more sociable and talkative.
Brain regions associated with threat, punishment, and negative affect seemed to have something to do with how neurotic participants were. Neuroticism includes elements of irritability, anxiety, and being self-conscious.
Brain areas dealing with information about the intentions and mental states of other people were associated with agreeableness. Cooperation, compassion and politeness are part of agreeableness.
The lateral prefrontal cortex, involved in planning and the voluntary control of behavior, seemed to be associated with conscientiousness. People who are highly conscientious tend to be self-disciplined and orderly, rather than impulsive.
The one major personality trait that did not have an association with a brain area volume in this study was openness/intellect, which includes people who are creative, philosophical, imaginative, and intellectually engaged. This is also the only trait that has been associated with intelligence in previous research. Further study would be needed to determine how biology might be related to this trait.
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