Extraversion Research Paper

Academic Writing Service

Sample Extraversion Research Paper. Browse other research paper examples and check the list of research paper topics for more inspiration. If you need a research paper written according to all the academic standards, you can always turn to our experienced writers for help. This is how your paper can get an A! Feel free to contact our custom research paper writing service for professional assistance. We offer high-quality assignments for reasonable rates.

Extraversion is one of the most-studied individual differences in psychology. It has been the focus of research attention for as long as personality psychology has existed; the trait or some variation of it has been included in virtually all comprehensive models of personality. Extraversion (also spelled extroversion) encompasses a set of characteristics including active engagement with the world, self-confidence, sociability, and the need for external stimulation. Yet, the defining characteristics and processes hypothesized to underlie the trait have varied considerably across theorists. Thus, the behavioral outcomes of extraversion such as leadership ability and the propensity to engage in impulsive behaviors might be related to one type of extraversion but not to others.

Academic Writing, Editing, Proofreading, And Problem Solving Services

Get 10% OFF with 24START discount code

1. Early History Of Extraversion

Precursors of the extraversion dimension appeared in the writings of the ancient Greeks and Romans. Hippocrates and Galen described a set of personality types that were based on the balance of four humors in the body, and these categories resemble the opposing poles of the modern extraversion–introversion dimension. In the early twentieth century, Wundt extended this ancient model, suggesting that the personality types that Hippocrates and Galen identified are not discrete categories, but continuous dimensions (for a historical overview of these models, see Eysenck and Eysenck 1985). Specifically, the personality dimension that is now thought of as extraversion–introversion was said to reflect a person’s propensity to have quickly changing emotions (extraversion) versus slowly changing or stable emotions (introversion). Thus, in Wundt’s formulation, when situations change, extraverts’ emotions change too, whereas introverts are left introspecting and reflecting.

Early theorists suggested that extraverts and introverts process information about the world in very different ways (for a review of early models, see Guilford and Braly 1930). Otto Gross, for example, proposed two personality types that were based on reactions following exposure to a stimulus. According to Gross, ‘primary’ functions are elicited immediately upon stimulation, and ‘secondary’ functions ‘persist after stimulation and permit organization and systematization of sense-impressions’ (Guilford and Braly 1930, p. 97). The ‘shallow–broad’ personality type was thought to have relatively high levels of primary function compared to secondary function, whereas the ‘deep–narrow’ type was thought to have relatively high levels of secondary function compared to primary function. Thus, the shallow–broad type (corresponding to the extravert) was predisposed to short-lived reactions to immediate situations, whereas the deep–narrow type (corresponding to the introvert) was more likely to introspect and brood about past events.

Citing work by Gross and others, Jung ([1921] 1971) proposed what is probably the first trait that was named extraversion introversion. According to Jung, the causal mechanism underlying extraversion can be traced to individual differences in orientation towards the external, objective world. Like Gross’s shallow– broad type, Jung’s extravert is characterized by immediate reactions to the objects and stimuli that he or she experiences. The introvert, on the other hand, is oriented toward the subjective feelings that an object or stimulus creates, just as the deep–narrow type is dominated by secondary processes. Extraverts react to the immediate features of the surrounding environment, whereas introverts are influenced by the subjective feelings that such stimuli arouse. Thus, extraverts were thought to be better able to adapt to the changing external environment and were seen as less prone to introspection.

Beginning in the 1930s, Guilford used factor analytic techniques to examine whether the different individual difference characteristics that researchers had been studying reflect a single unidimensional trait of extraversion. In a series of studies, Guilford found that extraversion measures were indeed multidimensional, containing two different ‘extraverted’ axes. He and his colleagues developed a series of scales to assess the various dimensions, culminating in the Guilford– Zimmerman Temperament Survey (Guilford and Zimmerman 1949). Their hierarchical questionnaire and model of personality included 11 primary traits and a number of higher-order factors. Two of the higher-order factors are relevant to the extraversion dimension: a social activity factor that includes ‘general activity,’ ‘ascendance,’ and ‘sociability’ and an impulsivity factor that includes the lack of ‘restraint’ and lack of ‘thoughtfulness.’ Following the lead of early personality theorists, Guilford labeled the impulsivity factor rather than the social activity factor as extraversion.

2. Hans Eysenck And The Arousal Model

Around the same time that Guilford was refining his measures, Hans Eysenck was developing his own comprehensive model of personality. His early work focused on identifying dimensions that underlie different forms of neuroses. According to Eysenck, extraversion emerged consistently as the second major factor that could account for variance in symptoms and behavioral tasks once a neuroticism factor was removed. Like Guilford, Eysenck believed that extraverts were primarily impulsive individuals and he was initially unwilling to include sociability as an important facet of the trait. Eventually, after substantial factor analytic work, Eysenck concluded that sociability and impulsivity were correlated and together they formed the higher-order trait of extraversion.

At the same time that Eysenck was constructing and refining his measures of extraversion, he was also developing an influential psychophysiological theory of extraversion. Originally, Eysenck proposed a theory of extraversion that was based on individual differences in excitation and inhibition. However, this theory was found to be insufficient and was quickly replaced with the arousal theory of extraversion (for a historical review of Eysenck’s models, see Eysenck and Eysenck 1985). According to the arousal theory, individual differences in extraversion result from differences in levels of general arousal, which in turn are linked to activity in the ascending reticular activation system (ARAS). Because introverts are thought to have low thresholds for ARAS activation, they are hypothesized to become more aroused when the ARAS is activated. Extraverts, on the other hand, are thought to have higher thresholds, and thus lower internal arousal. Eysenck also proposed that too much or too little arousal was detrimental to certain types of performance and was subjectively unpleasant. Thus, he could test the arousal hypotheses explicitly by examining performance and subjective enjoyment under conditions of varying stimulation. Extraverts should perform better than introverts and experience more enjoyment under arousing conditions because extraverts tend to be chronically underaroused in certain neural systems. To explain extraverts’ social behavior, Eysenck suggested that social situations are more arousing than nonsocial situations. Thus, extraverts tend to seek these situations, whereas introverts try to avoid them (for a critical review of the arousal theory, see Matthews and Gilliland 1999).

3. Extraversion And Reward-Sensitivity

Soon after Eysenck proposed the arousal hypothesis, Gray (1970) presented a modified version of the theory. Like Eysenck, Gray believed that a few major psychophysiological systems could explain most of the major variation in personality. However, Gray believed that evidence from studies of brain functioning did not support the extraversion and neuroticism dimensions that Eysenck proposed, and Gray proposed two dimensions that were rotated in factor analytic space from Eysenck’s original dimensions. Specifically, Gray argued that the Behavioral Inhibition System (BIS) controls responses to conditioned punishment and nonreward, and variation in the strength of this system leads to individual differences in anxiety. A second system, the Behavioral Activation System (BAS) controls responses to conditioned reward and nonpunishment and leads to individual differences in impulsiveness. Instead of attributing individual differences in personality to arousal, Gray suggested that extraversion and neuroticism result from individual differences in reward and punishment sensitivity. Extraversion reflects the relative strength of the BAS versus the BIS (extraverts have stronger BAS functions), and neuroticism reflects the combined strength of the BAS and the BIS (neurotics have strong BIS and BAS).

Ironically, although Gray labeled the dimension corresponding to the BAS as ‘impulsivity,’ many theorists who adopted Gray’s ideas downplayed this impulsivity label, focusing instead on a separate theoretical consequence of the BAS—high pleasant affect. For example, Tellegen (1985) suggested that extraversion is a broad dimension that reflects positive emotionality rather than impulsivity or sociability. Tellegen linked positive emotionality to Gray’s BAS, suggesting that reward-sensitive individuals were more likely to experience positive affect, and that the broad extraversion factor resulted from this underlying individual difference. Tellegen suggested that impulsivity should remain separate from this reward sensitivity positive emotionality dimension. Watson and Clark (1997) extended Tellegen’s argument, showing that the different facets of extraversion were often more strongly correlated with positive affect than they were with each other (suggesting that the various characteristics of extraverts were linked by their common associations with positive emotions); and Lucas et al. (2000) found that only the extraversion facets that reflect positive emotionality are associated with the higher-order trait. They suggest that characteristics of extraversion such as warmth, sociability, and dominance are the results of extraverts’ greater positive emotionality. DePue and Collins (1999) provided an updated reward sensitivity model based on dopamine systems in the brain.

4. Extraversion And The Big Five

At the same time that Guilford, Eysenck, and others were developing and revising self-report questionnaire measures of the constructs in their models of personality, other researchers were investigating an alternative approach to developing comprehensive models of personality. Beginning with Allport and Odbert (1936), researchers turned to natural language descriptors of personality to identify important personality dimensions. According to the lexical hypothesis, all important dimensions of personality should be represented in everyday language, and thus a systematic examination of personality descriptors should allow personality psychologists to identify these dimensions. Raymond Cattell’s early attempts to find the primary dimensions of natural language descriptors resulted in 16 separate traits, but a higher-order trait that resembles extraversion can be identified in his personality measures (Cattell et al. 1980). In other researchers’ analyses, factor analyses of personality descriptors often converged on five major factors (the ‘Five Factor Model’). The first and largest factor that emerges from these analyses (variously labeled ‘confident self-expression,’ ‘surgency,’ ‘assertiveness,’ ‘extraversion,’ and ‘power’) clearly reflects the extraversion dimension.

5. Modern Conceptualizations Of Extraversion

Most modern theories of extraversion include one or more of the following clusters of characteristics: warmth, gregariousness, and affiliation; assertiveness and ascendance; high levels of activity; and the tendency to experience pleasant emotions. Occasionally, theorists also emphasize extraverts’ ambition or their tendency to seek excitement (Watson and Clark 1997). A number of questionnaire measures are available to assess extraversion, including Costa and McCrae’s (1992) Revised NEO Personality Inventory Extraversion scale and Goldberg’s International Personality Item Pool (Goldberg, 1999). Goldberg’s large set of items includes many variations that allow researchers to assess diverse conceptualizations of the extraversion trait. The Eysenck Personality Inventory and Eysenck Personality Questionnaire are also still used widely.

6. Future Directions

Although much extraversion research has been based on exploring how general self-report items cluster together, a deeper understanding can be gained by including on-line recording of feelings and behavior, as well as biological measures. For example, researchers have examined the heritability of the trait and have linked reports of extraverted behaviors to specific neural systems, focusing on the neurotransmitters, hormones, and brain locations that appear to be responsible for extraverted behavior (for a review, see Depue and Collins 1999). This multimethod approach is necessary so that researchers can move beyond the simple analysis of how global self-report items cluster. By including on-line recording of behavior, as well as personality questionnaires and biological measures, we shall be better able to understand the major types of extraversion (e.g., the type based on impulsive sociability vs. the type based on high reactivity in the positive affect system), and the resultant behaviors of each.


  1. Allport G W, Odbert H S 1936 Trait-names: A psycho-lexical study. Psychological Monographs 47(1, Whole No. 211)
  2. Cattell R B, Eber H W, Tatsuoka M M 1980 Handbook for the Sixteen Personality Factor Questionnaire (16PF). Institute for Personality and Ability Testing, Champaign, IL
  3. Costa P T, McCrae R R 1992 Revised NEO Personality Inventory (NEOPI-R) and Five Factor Inventory (NEO-FFI) Professional Manual. Psychological Assessment Resources, Odessa, FL
  4. 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: 491–569
  5. Eysenck H J, Eysenck M W 1985 Personality and Individual Diff Plenum, New York
  6. Goldberg L R 1999 A broad-bandwidth, public-domain, personality inventory measuring the lower-level facets of several five-factor models. Available without cost at http://ipip.ori.org ipip/
  7. Gray J A 1970 The psychophysiological basis of introversion– extraversion. Behaviour Research and Therapy 8: 249–66
  8. Guilford J P, Braly K W 1930 Extroversion and introversion. Psychological Bulletin 27: 96–107
  9. Guilford J P, Guilford J S, Zimmerman W S 1949 The Guilford–Zimmerman Temperament Survey: Manual. Sheridan Psychological Services, Beverly Hills, CA
  10. Jung C G [1921] 1971 Psychological Types. Princeton University Press, Princeton, NJ
  11. Lucas R E, Diener E, Grob A, Suh E M, Shao L 2000 Cross-cultural evidence for the fundamental features of extraversion. Journal of Personality and Social Psychology 79: 452–68
  12. Matthews G, Gilliland K 1999 The personality theories of H. J. Eysenck and J. A. Gray: A comparative review. Personality & Individual Differences 26: 583–626
  13. Tellegen A 1985 Structures of mood and personality and their relevance to assessing anxiety, with an emphasis on self-report. In: Tuma A H, Maser J D (eds.) Anxiety and the Anxiety Disorders. Lawrence Erlbaum Associates, Hillsdale, NJ, pp. 681–706
  14. Watson D, Clark L A 1997 Extraversion and its positive emotional core. In: Hogan R, Johnson J, Briggs S (eds.) Handbook of Personality Psychology. Academic Press, San Diego, CA, pp. 767–93


Structures of Personality Traits Research Paper
Configurational Analysis Research Paper


Always on-time


100% Confidentiality
Special offer! Get 10% off with the 24START discount code!