LOCAL SHIFTS IN RELATIVE REINFORCEMENT RATE AND TIME ALLOCATION ON CONCURRENT SCHEDULES

Pigeons were exposed to mixed concurrent schedules featuring regular unsignaled changes in reinforcer distribution within a session. In 2 experiments, the number of shifts in reinforcer distribution within a session, the duration of exposure to a particular relative rate (component duration), and overall reinforcement rate were varied over conditions. Relative time allocation followed changes in reinforcer distribution more closely when there were fewer changes within a session, with longer components, and at higher overall rates of reinforcement. These data demonstrate that relative reinforcement rate or its constituents can control behaviour over a period of time briefer than that implied by most molar theories and that the period over which reinforcers affect subsequent behavior depends on overall reinforcement rate. Both a matching model and a weighted moving average model captured important features of the data.