Second-Order Schedules: Parametric Variation of Rate of Reinforcement

Pigeons’ responses were maintained under a second-order schedule where behavior controlled by a fixed-interval component was reinforced according to variable-interval schedules. Completion of each fixed interval produced a brief stimulus presentation; this stimulus was paired intermittently with food in some conditions but was not paired in other conditions. While the fixed-interval schedule was held constant, the value of the variable-interval schedule was parametrically varied over a wide range. Response rates decreased in an orderly fashion as the variable-interval value increased, while the degree of response patterning within fixed-interval schedules remained relatively constant. Comparisons of paired and nonpaired brief stimulus procedures failed to show any consistent differences in the control of rates or patterns of responding.