Actions and Habits: Psychological Issues in Dual-System Theory

Abstract

Instrumental behavior is controlled by two parallel systems that summate in the control of behavior. One system controls goal-directed action that is based on the interaction of a desire for the outcome of the action (desire criterion) with a belief that the action causes the outcome (belief criterion) through a process of practical inference. The desire criterion is assessed by outcome revaluation procedures, whereas the belief criterion requires that the revaluation effect be mediated by the instrumental, action–outcome contingency. The second system controls habitual responding, which fails to meet the joint requirements of the belief and desire criteria. Rather habits are elicited either directly by the training context or indirectly by a sensory expectation of the reinforcer of the habit and motivated by Pavlovian conditioned motivational states. Simulation of a dual-system theory, in which the instrumental beliefs of the goal-direct system are based on the experienced correlation between the action and outcome rates, explains how the sensitivity of performance to outcome revaluation varies with the reinforcement schedule, the amount of training, and choice rather than single-response training.