Abstract
Approach–avoidance theories describe the major systems that motivate behaviours in reaction to classes of appetitive (rewarding) and aversive (punishing) stimuli. The literature points to two major “avoidance” systems, one related to pure avoidance and escape of aversive stimuli, and a second, to behavioural inhibition induced by the detection of goal conflict (in addition, there is evidence for nonaffective behavioural constraint). A third major system, responsible for approach behaviour, is reactive to appetitive stimuli, and has several subcomponents. A number of combined effects of these systems are outlined. Finally, the hierarchical nature of behavioural control is delineated, including the role played by conscious awareness in behavioural inhibition