Learning About Absent Outcome in the Presence of Conditioned Excitor and Inhibitor: A Study Using Conditioned Flavor Preference

We examined whether aversive conditioning of a previously established conditioned inhibitor (A) for sucrose solution (X) affects subsequent consumption and aversive conditioning of X. Experiment 1 established an appetitive conditioned inhibition procedure in which odor A became a conditioned inhibitor for X. In Phase 1 of Experiments 2 and 3, subjects received either inhibitory (Group INH: AB/BX/C) or excitatory conditioning of A (Group EXC: ABX/B/C), or a control treatment (GroupCONT: AB/B/CX). In Phase 2, A was paired with an injection of lithium chloride (LiCl) and consumption of X was measured. X was paired with LiCl in Phase 3, and tested in extinction. After a moderate amount of Phase 1 treatment in Experiment 2, animals in Group EXC showed a reduction in consumption of X after A-LiCl pairings, while those in both Groups EXC and INH rapidly acquired an aversion to X during X-LiCl conditioning. However, when extended Phase 1 treatment was given in Experiment 3, animals in Group INH tended to acquire the aversion to X at a slower rate than those in Group CONT. Animals in Group EXC did not show any superiority in acquisition of theX aversion. The results are discussed in terms of mediation processes by event representations.