Incentive downshifts evoke search repertoires in rats

Negative incentive contrast effects (NCEs) have typically been attributed t o frustration or the decremental generalization of learned associations. Th e purpose of these experiments was to clarify the relation of NCEs to the r epertoires of functional search behaviors evoked by incentive downshifts. R ats shifted from 32% to 4% sucrose-solution decreased consummatory response s but increased nose-down locomotion, orientation, location entries, and sa mpling of alternatives relative to unshifted controls. These changes in beh avior were terminated or failed to occur under incentive upshifts. Furtherm ore, reward downshifts did not produce avoidance of the location of the shi fted incentive. Increased search occurred whether or not alternative reward locations were available. Together the evidence suggests that NCEs are rel ated to evoked search modes supporting a repertoire of functional behaviors related to finding food.