MOTIVATIONAL CONTROL OF HETEROGENEOUS INSTRUMENTAL CHAINS

The sensitivity of instrumental actions to a shift in motivational state was assessed as a function of each action's proximal or distal location to a food outcome within a heterogeneous chain. The chain consisted of either a lever press and a chain pull or a lever press and a magazine-panel response. In all studies, food-deprived rats received instrumental training before performance was tested in extinction while the animals were either food deprived or undeprived. Two main results were established: (a) When the animals were tested in the undeprived state, reexposure to the food outcome when undeprived prior to testing produced a relatively greater reduction in the test performance of distal than of proximal actions. Proximal actions were, however, depressed by the reexposure treatment. (b) In the absence of reexposure to the outcome in the undeprived state, the proximal actions were more sensitive than the distal ones to the deprivation state on test. It is concluded that the motivational control of instrumental performance varies as a function of the location of the action within a behavioral chain.