Extraversion

Definition

Extraversion is one of the most studied traits in personality psychology. Some form of the trait has been included in almost every comprehensive model of personality. At the broadest level of description, extraversion reflects the extent to which a person is interested in and enjoys social interaction. However, this broad trait also encompasses a number of more specific facets. For instance, each of the following facets has been included in at least one major model of extraversion: impulsivity, assertiveness, activity level, the tendency to engage in excitement-seeking behaviors, the experience of positive emotions, and feelings of warmth toward others. Given the relative diversity of these characteristics, it should be no surprise that psychologists disagree about which of these narrower facets is the defining feature of extraversion (or whether a defining feature even exists). Modern personality psychologists strive to resolve this debate and to understand the psychological and physiological processes that underlie this trait.

Models of Extraversion

The history of extraversion research is as long as the history of psychology itself. Precursors of the trait can be found in the writings of the ancient Greeks, though many psychologists trace the origin of modern extraversion research to Carl Jung. Jung believed that individuals varied in their orientation to the external world. Extraverts were thought to be characterized by strong and immediate reactions to the objective features of the environment. Introverts, on the other hand, were thought to be more tuned in to the internal, subjective feelings that objects in the world create. Thus, extraverts were thought to be adept at dealing with the changing external environment (and perhaps somewhat impulsive), whereas introverts were thought to be less adaptable and more prone to introspection.

Hans Eysenck built on the work of Jung (and others) and attempted to identify the processes that might underlie these extraverted thoughts and behaviors. Initially, Eysenck, like Jung, thought that extraverts were defined by their impulsivity and their tendency to react to changing external circumstances. He posited that individual differences in this characteristic were [Page 335]due to differential levels of excitation and inhibition. Specifically, Eysenck believed that extraverts were characterized by weak and slowly developing excitation, as well as strong and quickly developing inhibition. Thus, extraverts conditioned (or learned) slowly and got bored with repetitive tasks quickly. As a result of these underlying processes, extraverts were poorly socialized and craved changing conditions.

This initial model was found to be insufficient, and Eysenck quickly replaced it with a model based on individual differences in arousal. According to this revised model, extraverts were characterized by relatively low levels of arousal, whereas introverts were characterized by relatively high levels of arousal. Because too little or too much arousal impairs performance and is subjectively unpleasant, extraverts and introverts should seek out different types of environments. Extraverts should choose and enjoy highly arousing situations like parties or risky activities, whereas introverts should choose and enjoy more sedate activities likely spending time alone or interacting with a relatively small number of friends. Eysenck tested his model by examining extraverts' and introverts' performance in conditions that varied in their level of stimulation.

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