Date of Graduation


Document Type


Degree Type



Eberly College of Arts and Sciences



Committee Chair

Kennon A Lattal


In the most common operant procedure involving magnitude of reinforcement, single reinforcers, of one magnitude or the other, are available from the same source (with pigeons, a food hopper) at different times. The duration of access as a source of discriminative control by these reinforcers comes sometime after their onset, when one reinforcer continues for a longer duration than the other. Thus, reinforcers of different durations can be differentially reinforcing only after the passage of some time. In the current experiment, four pigeons responded on a single-key concurrent variable-time schedule of reinforcement. Two reinforcer durations, 2 s and 6 s, were delivered within components of the concurrent schedule. This allowed covariation of magnitude within components while simultaneously covarying onset stimuli (red, green, and white hopper lights) between components. Time allocation to the schedule components did not vary as a function of differentially signaling reinforcer onset between components. Post-reinforcement pausing did vary as a function of the reinforcer duration: longer pausing occurred after 6-s reinforcers and shorter pausing occurred after 2-s reinforcers. These findings extend the generality of post-reinforcement pausing to variable-time schedules of reinforcement.