Individual differences |
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Extraversion is "the act, state, or habit of being predominantly concerned with and obtaining gratification from what is outside the self". Extraverts tend to be very socialble and to be assertive, enthusiastic, talkative, and gregarious. They take pleasure in activities that involve large social gatherings, such as parties, community activities, public demonstrations, and business or political groups. Politics, teaching, sales, managing, brokering are fields that favor extraversion. An extraverted person is likely to enjoy time spent with people and find less reward in time spent alone. They enjoy risk-taking and often show leadership abilities.
An extravert is energized when around other people. Extraverts tend to "fade" when alone and can easily become bored without other people around. Extraverts tend to think as they speak. When given the chance, an extravert will talk with someone else rather than sit alone and think.
Measurement of extraversion
Neuroscience of extraversion
Hans Eysenck proposed that extraversion was caused by variability in cortical arousal. He hypothesized that introverts are characterized by higher levels of activity than extraverts and so are chronically more cortically aroused than extraverts. The fact that extraverts require more external stimulation than introverts has been interpreted as evidence for this hypothesis. Other evidence of the "stimulation" hypothesis is that introverts salivate more than extraverts in response to a drop of lemon juice.
Extraversion has been linked to higher sensitivity of the mesolimbic dopamine system to potentially rewarding stimuli. This in part explains the high levels of positive affect found in extraverts, since they will more intensely feel the excitement of a potential reward. One consequence of this is that extraverts can more easily learn the contingencies for positive reinforcement, since the reward itself is experienced as greater.
One study found that introverts have more blood flow in the frontal lobes of their brain and the anterior or frontal thalamus, which are areas dealing with internal processing, such as planning and problem solving. Extraverts have more blood flow in the anterior cingulate gyrus, temporal lobes, and posterior thalamus, which are involved in sensory and emotional experience. This study and other research indicates that introversion-extraversion is related to individual differences in brain function.
References & Bibliography
- Merriam Webster Dictionary.
- Extroversion Gale Encyclopedia of Childhood & Adolescence. Gale Research, 1998.
- Lemon juice experiment Wired-up March 18, 2005, issue: 22. Note that this is an online demonstration of research published in peer reviewed journals.
- Depue, R. A., & Collins, P. F. (1999). Neurobiology of the structure of personality: Dopamine, facilitation of incentive motivation, and extraversion. Behavioral and Brain Sciences, 22, 491–517.
- Johnson, D. L., Wiebe, J. S., Gold, S. M., Andreasen, N. C. (1999). Cerebral blood flow and personality: A positron emission tomography study. American Journal of Psychiatry, 156, 252–257.