Effects of a signaled delay to reinforcement in the previous and upcoming ratios on between-ratio pausing in fixed-ratio schedules.

Domestic hens responded under multiple fixed-ratio fixed-ratio schedules with equal fixed ratios. One component provided immediate reinforcement and the other provided reinforcement after a delay, signaled by the offset of the key light. The components were presented quasirandomly so that all four possible transitions occurred in each session. The delay was varied over 0, 4, 8, 16, and 32 s with fixed-ratio 5 schedules, and over 0, 8 and 32 s with fixed-ratio 1, 15 and 40 schedules. Main effects of fixed-ratio value and delay duration were detected on between-ratio pauses. Pauses were longer when the multiple-schedule stimulus correlated with a delayed-reinforcer component was presented, with the longest pauses occurring at the transition from a component with an immediate reinforcer to one with a delayed reinforcer. Pause durations were shortest during immediate components. Overall, both the presence or absence of a delay in the upcoming component, and the presence or absence of a delay in the preceding component affected pause length, but the upcoming delay had the larger effect. Thus changes in delay had similar effects to past reports of the effects of changes in response force, response requirement, and reinforcer magnitude in multiple fixed-ratio fixed-ratio schedules.