Single-incentive selective associations produced solely as a function of compound-stimulus conditioning context.

Barpressing was maintained in a tone-plus-light (TL) condition in 2 groups of rats by shock-related contingencies and in 2 other groups by food-related contingencies. Responding ceased in TL absence (TL). Contingency arrangements made TL hedonically positive, relative to TL, for 1 shock group and for 1 food group and hedonically negative for 1 shock group and for 1 food group. In a stimulus-element test, the visual modality was dominant when TL was hedonically positive, whereas auditory control increased when TL was negative, irrespective of the reinforcers involved. Within-incentive contingency manipulations produced selective associations hitherto ascribed to stimulus-reinforcer interactions, suggesting that biological constraints on learning may operate at the level of conditioned psychological states.