Search Here

Extroverted personalities are often associated with characteristics such as being outgoing, adventurous and generally more cheerful. Although researchers know that people's temperament and personalities are most likely innate, they have not figured out how certain biological mechanisms can be at work in creating these types of characteristics. Now, a new study conducted by Cornell neuroscientists suggest that extroverted personalities could be tied to how the brain responds to rewards.

The co-authors of the study, Richard Depue, a professor of human development in the college of Human Ecology and Yu Fu, a graduate student looked into how the brain reacts to rewards. The researchers recruited 70 young adult men who were a good mixture of introverts and extroverts, which were measured via a standard personality test.

For the first four days, the researchers administered Ritalin to half of the participants while the other half received a placebo. Ritalin is known for its ability to get the brain to release dopamine. The researchers then looked at how participants unconsciously associated contextual clues from video clips with reward. The participants who associated the clues with reward more frequently released more dopamine in the brain. The researchers found that participants who more frequently associated the clues with reward were mostly extroverts.

"Rewards like food, sex and social interactions as well as more abstract goals such as money or getting a degree trigger the release of dopamine in the brain, producing positive emotions and feelings of desire that motivate us to work toward obtaining those goals. In extroverts, this dopamine response to rewards is more robust so they experience more frequent activation of strong positive emotions," Depue said. "Dopamine also facilitates memory for circumstances that are associated with the reward. Our findings suggest this plays a significant role in sustaining extroverted behavior."

The study, "On the Nature of Extraversion: Variation in Conditioned Contextual Activation of Dopamine-Facilitated Affective, Cognitive and Motor Processes", was published in the Frontiers in Human Neuroscience. It was partly funded by the National Institute of Mental Health.