Restricted Access to Collateral Behavior Affects Operant Behavior on Variable-Interval Schedules

Abstract

Two experiments investigated moment-to-moment interactions between collateral and operant behaviors. Rats’ lever pressing was reinforced with food on a variable-interval (VI) schedule. In Experiment 1, access to water was first freely available and then presented in 10-s probes at different times within the interreinforcement intervals on the VI schedule. With free access to water, drinking occurred immediately after food reinforcement and lever pressing was suppressed. Drinking occurred during probes and the extent of drinking and the degree of suppression of lever pressing depended upon the probe position within the VI schedule. In Experiment 2, access to wheel running was first presented in probes ranging from 2 to 128 s. Probes controlled a changeover to wheel running and caused a suppression in lever pressing. When wheel running was accessible most of the session time, periods of no access to running were scheduled as probes for 2 to 128 s. Cessation of wheel running during probes increased the momentary probability of lever pressing. In both experiments, restricted access to the collateral response resulted in an increase of the momentary probability of that response and a concomitant reduced probability of the operant response. The experiments demonstrate the feasibility of the probe technique in analyzing and controlling moment-to-moment patterns of collateral and operant behaviors.