Biological Bases of Extraversion Psychophysiological Evidence

Abstract

There is a good deal of evidence, particularly from electrodermal and electrocortical recording procedures, that introverts exhibit greater reactivity to sensory stimulation than extraverts. There is little evidence that introverts and extraverts differ in base level of arousal in neutral conditions, and there is no clear evidence that their differences in sensitivity to stimulation are determined by differences in attentional state. Faster auditory brainstem evoked response latencies observed for introverts implicate differences in peripheral sensory processes that are not determined by mechanisms in the reticular system as proposed in the arousal hypothesis. There is also evidence that individual differences in the expression of motor activity between introverts and extraverts involve differences in motoneuronal excitability.

The impact of personality on the reporting of unfounded symptoms and illness.

“…Introversion (low extraversion) is associated with greater physiological responsivity to sensory stimuli such as pain (Stelmack, 1990). In spite of having higher thresholds for pain, extraverted individuals, as shown by evidence from samples of chronic pain sufferers, are more likely to report pain symptoms than introverted individuals (Harkins, Price, & Braith, 1989;Philips & Jahanshahi, 1985;Wade, Dougherty, Hart, Rafii, & Price, 1992).…”

Sensitivity of the autonomic nervous system to visual and auditory affect across social and non-social domains in Williams syndrome

“…Whereas extraverts seek more frequent and intense stimulation (e.g., social interaction) to raise their inherently low level of arousal to an optimal level, introverts tend to exhibit the opposite pattern. Thus, compared to extraverts, introverts are thought to be inherently more aroused and arousable (Stelmack, 1990;Smith, 1994); exhibit higher HR reactivity (Smith et al, 1995); higher skin conductance levels (SCL; Smith et al, 1986); greater phasic skin conductance response (SCR; Smith et al, 1990); and slower electrodermal habituation (Smith et al, 1995). Although some aspects of this theory have been questioned (see e.g., Beauducel et al, 2006, for a discussion), it is nevertheless of interest to explore how the WS social profile of anxiousness coupled with hypersociability and its ANS correlates fit in with this line of research, as some behavioral features resemble typical extraverted behavior.…”

Extraversion and Alcohol: Eysenck’s Drug Postulate Revisited

“…Most often, individual differ ences in response to alcohol are explained in terms of Eysenck's drug postulate [2,6,7], Within the framework of this postulate, Eysenck combined the concept of indi vidual differences in cortical arousal of introverts and extraverts with the concept of a sedation threshold [8] and the Yerkes-Dodson law [9], The Yerkes-Dodson law states that performance on psychological tasks is a curvi linear or inverted-u function of level of motivation (arousal) and that this relationship is mediated by task difficul ty. Thus, introverts, if they are characterized by a higher level of arousal than extraverts, would perform a moder ately difficult task better than extraverts under low-stress conditions and would perform less well under high-stress conditions [10,11], Although there is little evidence that introverts and extraverts differ in tonic or base level of arousal, psychophysiological findings suggest that intro verts and extraverts can be distinguished by differences in arousability [11]. For example, there is considerable evi dence of systematic differences in response to stimulation when base levels of arousal are experimentally manipu lated with stimulant and sedative drugs [7,[12][13][14][15].…”