In Brief

Extraverts find social situations more rewarding than introverts, not because they are more sociable, but because they are more sensitive to the rewards inherent in most situations, finds a recent study.

The article, by Richard E. Lucas, PhD, Ed Diener, PhD, and colleagues of the University of Illinois at Urbana­ Champaign, appeared in the Journal of Personality and Social Psychology (Vol. 79, No. 3).

Arguing that sociability is a narrower construct than extraversion and not the core of the trait, the researchers conducted three studies on a total of 743 U.S. college students to test how extraversion and reward sensitivity are linked. They created a Social Interaction Scale to assess whether people base their enjoyment of situations primarily on the extent to which the situations provide opportunities for social interaction. The study also examined three other facets of extraversion: affiliation, defined as enjoying and valuing close interpersonal bonds; ascendance, which reflects enjoying leadership roles and assertiveness; and venturesome, the degree to which individuals seek out and enjoy exciting, stimulating situations.

The researchers found that, although sociability--individual differences in enjoying social activities and preferring being with others over being alone--is an important part of extraversion, it may actually be a by-product of reward sensitivity rather than a core feature of extraversion.

The authors also point to prior research that shows extraverts tend to feel more pleasant affect even when they are alone.

"Both extraverts and introverts benefit from social interaction," said the authors. "However, extraverted participants did not spend any more time in social situations than introverted participants, but reported more pleasant affect even when alone, both indicating that some additional factor had to be accounting for their greater reported happiness."

By examining the structure of the relationship of aspects of extraversion and pleasant affect, the authors found that extraverts may be drawn to social situations for rewards such as warmth, affection and close emotional bonds, and, therefore, should be more likely than introverts to engage in rewarding social and nonsocial situations, but not in less rewarding social situations.

The researchers followed up these studies with another involving more than 6,000 college students from 39 other countries. They found cross-cultural support for their contention that sensitivity to rewards forms the core of extraversion. In analyzing the results, the researchers argued that social activity may serve different functions in different cultures.

--D. SMITH