ABSTRACT
Equally crucial to the survival of any organism is the notion of appetitive control, when behaviour is motivated by increasing contact with stimuli that are pleasant or otherwise reinforcing. One of the key behavioural principles that influences the practice of Acceptance & Commitment Therapy is the notion that the behaviour of any organism can be grouped into one of two broad functional classes: behaviour under appetitive control; and behaviour under aversive control. Behaviours under appetitive control might appear to be very diverse but because the purpose of them is the same, they can be considered to be functionally equivalent. In the service of promoting adaptive behaviour change, it is helpful for practitioners to firmly appreciate that behaviour does not exist in a vacuum. The notion of appetitive and aversive control is key to understanding the psychological context in which behaviour occurs, and therefore its function.
