Reinforcement sensitivity theory

Reinforcement sensitivity theory (RST) proposes three brain-behavioral systems that underlie individual differences in sensitivity to reward, punishment, and motivation. While not originally defined as a theory of personality, the RST has been used to study and predict anxiety, impulsivity, and extraversion. The theory evolved from Gray's biopsychological theory of personality to incorporate findings from a number of areas in psychology and neuroscience, culminating in a major revision in 2000. The revised theory distinguishes between fear and anxiety and proposes functionally related subsystems. Measures of RST have not been widely adapted to reflect the revised theory due to disagreement over related versus independent subsystems. Despite this controversy, RST informed the study of anxiety disorders in clinical settings and continues to be used today to study and predict work performance. RST, built upon Gray's behavioral inhibition system (BIS) and behavioral activation system (BAS) understanding, also may help to suggest predispositions to and predict alcohol and drug abuse. RST, a continuously evolving paradigm, is the subject of multiple areas of contemporary psychological enquiry. Gray's biopsychological theory of personality was informed by his earlier studies with Mowrer on reward, punishment, and motivation and Hans Eysenck’s study of the biology of personality traits. Eysenck linked Extraversion to activation of the ascending reticular activating system, an area of the brain which regulates sleep and arousal transitions. Eysenck's two original personality factors, Neuroticism and Extraversion, were derived from the same lexical paradigm used by other researchers (e.g., Gordon Allport, Raymond Cattell) to delineate the structure of personality. Eysenck’s Extraversion-Arousal Hypothesis states that under low stimulation conditions, introverts (defined as low in Extraversion) will be more highly aroused than extraverts; however, under high stimulation, introverts may become over-aroused, which will feedback within the ascending reticular activating system and result in decreases in arousal.