Motivating operations in appetite research.

Appetite research frequently employs principles derived from behaviour analysis. However, it has yet to utilise the more recent theoretical advances in this field. This paper describes the concept of the motivating operation (MO)--a behaviour analytic formulation of motivation. An MO is an environmental event that (a) establishes or abolishes the reinforcing or punishing effect of another event and (b) evokes or abates behaviours associated with that event. The paper describes both unconditioned and conditioned MOs and the ways in which they may help account for a variety of eating behaviours. It then goes on to highlight the main ways in which the MO account differs from other theories of motivation employed in appetite research. These relate to (1) the ways in which they account for non-regulatory feeding, (2) the extent to which they address cognitive variables and (3) their underlying philosophical assumptions and subsequent relation to intervention.