<P> Statement measures tend to comprise more words, and hence consume more research instrument space, than lexical measures . Respondents are asked the extent to which they, for example, Talk to a lot of different people at parties or Often feel uncomfortable around others . While some statement - based measures of extraversion / introversion have similarly acceptable psychometric properties in North American populations to lexical measures, their generally emic development makes them less suited to use in other populations . For example, statements asking about talkativeness in parties are hard to answer meaningfully by those who do not attend parties, as Americans are assumed to do . Moreover, the sometimes colloquial North American language of statements makes them less suited to use outside America . For instance, statements like Keep in the background and Know how to captivate people are sometimes hard for non-native English - speakers to understand except in a literal sense . </P> <P> Hans Eysenck described extraversion - introversion as the degree to which a person is outgoing and interactive with other people . These behavioral differences are presumed to be the result of underlying differences in brain physiology . Eysenck combined cortical inhibition and excitation with the ascending reticular activation system (ARAS), a pathway located in the brainstem . Extraverts seek excitement and social activity in an effort to heighten their arousal level, whereas introverts tend to avoid social situations in an effort to keep such arousal to a minimum . Eysenck designated extraversion as one of three major traits in his P-E-N model of personality, which also includes psychoticism and neuroticism . </P> <P> Eysenck originally suggested that extraversion was a combination of two major tendencies, impulsiveness and sociability . He later added several other more specific traits, namely liveliness, activity level, and excitability . These traits are further linked in his personality hierarchy to even more specific habitual responses, such as partying on the weekend . </P> <P> Eysenck compared this trait to the four temperaments of ancient medicine, with choleric and sanguine temperaments equating to extraversion, and melancholic and phlegmatic temperaments equating to introversion . </P>

Who has classified introvent personality and extrovert personality