Multiple schedules, off-baseline reinforcement shifts, and resistance to extinction.

Resistance to extinction in a target multiple-schedule component varies inversely with the rate of reinforcement arranged in an alternative component during baseline. The present experiment asked whether changing the reinforcer rate in an alternative component would impact extinction of target component responding if those changes occurred in an off-baseline phase during which the target component was never experienced. Pigeons' key pecking was studied in three types of conditions, and each condition consisted of three phases. In Phase 1, pecking produced food in the target and alternative components of a multiple schedule according to variable-interval 60-s schedules. In Phase 2, the alternative-component stimulus was presented alone in a single schedule. Pecking during this phase produced the same reinforcer rate as in baseline in the Control condition, a higher rate of food (variable-interval 15 s) in the High-Rate condition, or was extinguished in the Extinction condition. Extinction of target- and alternative-component key pecking then was assessed in a multiple schedule during the final phase of each condition. Resistance to extinction of target-component key pecking was the same between the Control and High-Rate conditions but lower in the Extinction condition. These findings are discussed in terms of discrimination and generalization processes.