Perceptual learning in flavor preference conditioning: Restricting generalization of acquired preferences between flavors

Two experiments with rats investigated perceptual learning using a conditioned preference procedure. Experiment 1 used a between-subject procedure in which rats received either intermixed preexposure (AX, BX, AX, BX…) or blocked preexposure (AX, AX…, BX, BX…) to flavor compounds before a conditioned preference was established to AX by pairing it with sucrose. During a test, rats given intermixed preexposure showed a greater preference for AX over BX than those given blocked preexposure. Experiment 2 showed that after intermixed preexposure to AX and BX, and a block of preexposure to CX, a preference established to AX was less likely to generalize to BX than to CX. These results represent the first demonstration of the impact of the schedule of preexposure on perceptual learning using a flavor preference procedure, and they parallel those previously observed using flavor aversion procedures.