COMPARING THE MAGNITUDES OF 2ND-ORDER CONDITIONING AND SENSORY PRECONDITIONING EFFECTS

Water-deprived rats served in a conditioned lick-suppression experiment designed to test the hypothesis that second-order conditioning is more robust than sensory preconditioning with equivalent parameters. The second-order and sensory preconditioning paradigms are identical except for the ordering of Phase 1 and Phase 2. In second-order conditioning, S1 immediately precedes the US during Phase 1 (i.e., S1→US), and S2 immediately precedes S1 during Phase 2 (i.e., S2→S1). In sensory preconditioning, these phases are reversed, such that S2 precedes S1 during Phase 1 (i.e., S2→SI) and S1 precedes the US during Phase 2 (i.e., SI→US). Thus, in second-order conditioning, S1 becomes excitatory prior to S2-S1 pairings. This would suggest a positive bias toward attending to S1 during S2-S1 pairings in second-order conditioning but not in sensory preconditioning, a condition that might render second-order conditioning more effective. The results indicated the presence of both second-order conditioning and sensory preconditioning effects, but they did not support the hypothesis that second-order conditioning is a more robust conditioning phenomenon than sensory preconditioning. © 1991, The Psychonomic Society, Inc.. All rights reserved.