Unequal associative changes when excitors and neutral stimuli are conditioned in compound

In four experiments a compound of a previously conditioned excitor and a ne utral stimulus was either reinforced with food or nonreinforced. Two experi ments used a magazine approach procedure in rats, and two used an autoshapi ng procedure in pigeons. All experiments employed a novel compound test pro cedure, which permitted evaluation of the size of the associative change th at took pla ce for the excitatory and neutral stimuli. Reinforcement of the compound resulted in greater increments in the associative strength of the neutral stimulus than of the excitor. Nonreinforcement of the compound res ulted in greater decrements in the associative strength of the excitor than of the neutral stimulus. These results agree with earlier experiments with compounds of excitors and inhibitors and provide an additional challenge t o contemporary error-correction models of conditioning.