Extraversion, Psychoticism and Sensitivity to Reward: Neurophysiological Basis of Two Personality Constructs

Gray's theory offers arguably the best to nowadays neurophysiological explanation of personality. One of its most polemical issues is the rela.tionships between reward sensitivity, which depends primarily on the activi.ty of dopaminenergic brain structures, and personality constructs of Extraver.sion and Psychoticism. One part of the researchers, including Gray, links the high activity of dopaminenergic brain structures to Psychotism while others connect it to Extraversion. By contrast, the author argues that the high activity of dopaminenergic brain structures, which mediates the activation of beha.viour, is typical of both extraverts and high Psychoticism scorers. Meantime, such feature of extraverts as their posi.tive emotionality and sociability might depend on other mechanisms, arguably on the activity of the opiate brain sy.stem. This is illustrated by a series of empirical research that shows that the psychometric scales created for measu.ring behavioural activation can correla.te with either Extraversion or Psycho.ticism depending on whether those who created these scales had conside.red positive emotionality an attribute of behavioural activation or not. The second series of empirical research de.monstrates that under conditions of psychophysiological experiment the scale of behavioural activation (linked to Extraversion) helps detect subjects who show higher electrophysiological manifestation of emotional arousal in a reward situation. The third series of research shows that the scale of beha.vioural activation linked to Psychotism is one of the strongest predictors of substance use. Extraversion may also be a risk factor but it is also positively related to subjective well.being, educa.tional aspiration, and good rela.tionships with parents which act as protective factors for problem behavio.ur.