J. A. Grayʹs reinforcement sensitivity theory: tests of the joint subsystems hypothesis of anxiety and impulsivity

Two experiments tested a new perspective on J. A Grayʹs Reinforcement Sensitivity Theory (RST) which postulates that the behavioural inhibition system (BIS) and the behavioural approach system (BAS) exert two separate effects on behaviour: (1) facilitatory (BIS−punishment, BAS−reward), and (2) antagonistic (BIS−reward, BAS−punishment). This joint subsystems hypothesis was contrasted with the conventional separable subsystems hypothesis of independent effects of the BIS and BAS in two paradigms: (1) affective modulation of the acoustic startle reflex (n=70), to measure the induction of emotional state; and (2) a visual information processing task with manipulations of reinforcement (feedback-alone vs. punishment of commission errors) and arousal (500 mg caffeine citrate vs. placebo; n=120), to measure behavioural inhibition/disinhibition. Consistent with the joint subsystems hypothesis: (1) high anxiety strengthened affective (electromyographic) reactions in the presence of unpleasant (compared with neutral) slides (i.e. fear potentiation), but this effect was stronger in low impulsivity participants (i.e. high impulsivity seemed to antagonise this BIS−mediated reaction); and (b) avoidance of punishment of incorrect responses was poorest in low anxiety, high impulsivity participants, pointing to a disinhibited pattern of reaction in individuals who, putatively, have a weak BIS and a strong BAS (this effect was found only in the caffeine group, suggesting that high levels of arousal may be necessary for the invigoration of disinhibitory behaviour). The implications of the joint subsystems hypothesis and the present data for Grayʹs reinforcement sensitivity theory of personality are discussed.