Abstract
The performance of pigeons was studied on a multiple schedule in which a three-member FR chained schedule alternated with a three-member FR tandem schedule. The chain and tandem schedules contained identical response requirements. In the chained schedule, more pausing and lower response rates occurred in the first and second components than occurred in the tandem control, in which the same exteroceptive stimulus was associated with all components. Because the reinforcement and response contingencies were identical in the chain and tandem schedules, differences in performances can be attributed to stimulus control.