The effects of intermittent schedules of reinforcement for pausing were evaluated in two experiments. In Experiment 1, across a series of conditions, a variable-interval (VI) baseline schedule, in which pigeons' key pecks produced food, alternated with conditions in which food was delivered according to a concurrent VI (for key pecking) tandem variable-time differential-reinforcement-of-other-behavior (DRO) 5-s schedule. Time spent pausing within a session was proportional to the reinforcement rates associated with the tandem schedule. To examine the control of pausing by antecedent events, Experiment 2 arranged a multiple schedule in which pecking and pausing in either component were maintained according to concurrent schedules like those used in the first experiment. The availability of reinforcement for pausing was signaled in one component while signals uncorrelated with reinforcement were presented in the other. Signaled reinforcement for pausing, relative to the presentation of uncorrelated signals, decreased time spent pausing, a finding consistent with existing research on the effects of signaled VI reinforcement for key pecking in pigeons. The results of the two experiments show that pausing functions as an operant in much the same way that discrete responses, like key pecks, do, and that pausing and other operants are similarly affected by both antecedent and consequent events.

No abstract

Animal trainers and others often recommend the use of jackpot reinforcers, which are disproportionally large and come as a "surprise" to the animals. Because the actual behavioral effects of these jackpots remain uninvestigated, many basic questions about their use and even definition are unanswered. This series of experiments explored the definitions of jackpots using several different behavioral tests with both rats and pigeons. Because the original description of a jackpot resembled the reinstatement of previously reinforced and extinguished responding with response-independent deliveries of reinforcer, reinstatement effects of a jackpot, defined by its quality, were examined with rats in Experiment 1. In Experiment 2, response-potentiating effects of response-independent and -dependent deliveries of a jackpot, defined by its quantity, were assessed with pigeons when responding had nearly ceased. The response-potentiating effects of the frequency of jackpot-reinforcer delivery were investigated when responding of pigeons was maintained in single (Experiment 3) or concurrent (Experiment 4) schedules of reinforcement. Effects of jackpots on resistance to change were assessed with rats in Experiment 5. The effects of jackpots in each experiment were either absent or unsystematic across the subjects, casting doubt on their utility in animal training. Possible factors contributing to the negative results are discussed.

Timeout punishment is among the most commonly reported disciplinary procedures (Barkin, Scheindlin, Ip, Richardson, & Finch, 2007). Despite the frequent use of timeout, little basic research has systematically examined different schedule effects of timeout from positive reinforcement. Using pigeons as subjects, the current series of experiments arranged variable schedules of timeout from positive reinforcement within a multiple-schedule arrangement where 20-s timeouts were response-dependent, response-independent, and delayed. Experiment 1 used a within-subject yoking procedure to compare schedules of variable-ratio (VR) and yokedinterval (YI) timeouts. Experiment 2 arranged separate parametric analyses of variable-interval (VI) and VR schedules of timeout. Within-session, yoked-control components delivered response-independent timeouts according to the same temporal distribution as in the preceding response-dependent timeout components in an attempt to isolate a direct response-decreasing effect of timeout presentations from indirect reductions in reinforcement rate. In Experiment 3, delays to timeout were studied using the same yoked-control procedure as in Experiment 2. Experiment 4 was designed to address confounds in the control conditions that were arranged for reduced timeout rate during delays in Experiment 3. The primary findings were: 1) responsedependent VR 2 and VR 3 timeout resulted in the most response reduction and the highest timeout rates across Experiments 1, 2, 3, and 4, 2) schedules of VI timeout reduced responding relative to baselines for the most frequent mean schedule values in Experiments 1 and 2, 3) response rate increases occurred during the introductions of delays to timeout in Experiment 3 and were partially attributed to the introduction of the delays in Experiment 4, and 4) response rates in the response-dependent timeout components were not always lower than their corresponding response-independent timeout components.

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.