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| Extending the Effects of Negative Incentive Shifts: Pausing in Pigeons, Primates, and People |
| Tuesday, May 31, 2005 |
| 10:30 AM–11:50 AM |
| Boulevard B (2nd floor) |
| Area: EAB; Domain: Basic Research |
| Chair: Chad M. Galuska (University of Michigan) |
| Discussant: Gregory J. Madden (University of Wisconsin-Eau Claire) |
| Abstract: The current symposium includes research directed toward extending the finding that discriminable transitions from favorable to unfavorable conditions of reinforcement produced disruptions in behavior in the form of extended pausing on schedules of positive reinforcement. In the first set of experiments, rhesus monkeys paused for extended durations when in transition from a ratio schedule ending in a large dose of cocaine to a ratio schedule ending in a small dose. In the second set of experiments, pigeons’ pauses in the transitions from a rich to a lean schedule were modulated as the result of segmenting, or chaining, one of the two schedules. Finally, adult humans with mental retardation paused for extended durations in rich-to-lean transitions of monetary reinforcement, and this effect was attenuated when a timeout was imposed following reinforcement. Overall, the these data confirm that negative incentive shifts in reinforcement conditions may engender behavioral disruptions in populations as diverse as developmentally disabled persons and drug users, and suggests potential methods for attenuating these disruptions. |
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| Fixed-Ratio Schedules of Cocaine Self-Administration in Rhesus Monkeys: Joint Control of Responding by Past and Signaled Upcoming Doses |
| CHAD M. GALUSKA (University of Michigan), Gary B. Duma (University of Michigan), Gail Winger (University of Michigan), James H. Woods (University of Michigan) |
| Abstract: Four rhesus monkeys self-administered cocaine according to a multiple fixed-ratio x fixed-ratio x schedule. Completion of the ratio in one component resulted in a small dose, while completion of the ratio in the other component resulted in a large dose. Components were arranged so that, following each infusion, there was an equal probability that the next dose would be large or small. This resulted in four types of transitions in which pauses were measured: From a small dose to a small dose; small to large; large to large; and large to small. The small and large doses varied across conditions (the large was always ten times that of the small) and at each dose comparison, ratio requirements ranging from 30 to 150 were investigated. At lower ratios and doses, pauses were brief and run rates were controlled by the upcoming dose. At larger ratios, pauses were pronounced, and run rates suppressed, in transitions from a large to a small dose. The behavioral disruption engendered by this transition occurred in all dose combinations investigated, but was attenuated at higher doses. The results suggest that negative discriminable shifts in drug availability may engender undesirable behavior among drug users in natural settings. |
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| Pausing in the Transitions Between Simple and Chained Fixed-Interval Schedules: Effects of Segment Length and Reinforcer Magnitude |
| TAMMY WADE-GALUSKA (West Virginia University) |
| Abstract: Simple schedules of reinforcement typically are preferred to chained schedules of equal duration. In the current study, pigeons served in two experiments designed to test whether the juxtaposition of simple and chained schedules would engender the disruption in behavior typically observed in the transition from favorable to unfavorable conditions of reinforcement. In the first experiment, a multiple schedule was employed in which a simple fixed-interval schedule alternated irregularly with a chained fixed-interval fixed-interval schedule. Across conditions, the length of the first segment of the chained schedule was manipulated while the total duration of the links comprising the chained schedule remained equal to that of the simple schedule. Only half the pigeons paused for an extended duration in the simple-to-chain transition as predicted, and this occurred only when the first segment was short. In a second experiment, a (rich) schedule ending in a large reinforcer was juxtaposed with a (lean) schedule ending in a small reinforcer. Across conditions, either the rich or lean schedule was segmented. Pausing was extended in the rich-to-lean transition as shown in previous research. In addition, this effect was enhanced when lean schedule was chained and attenuated when the rich schedule was chained. |
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| Experimenter-Imposed Delays Attenuate Disruptive Effects of Negative-Incentive Shifts in Humans |
| ADAM H. DOUGHTY (University of Kansas, Parsons), Dean C. Williams (University of Kansas, Parsons), Michael Perone (West Virginia University) |
| Abstract: Four adult humans with mental retardation initially were exposed to a two-component multiple schedule. In one component, a large fixed-ratio (FR) schedule operated in which the completion of a ratio resulted in a point that was exchangeable for a penny after the session (hereafter, the lean component). In the other component, a small FR schedule was in effect in which a ratio completion resulted in the delivery of a quarter (hereafter, the rich component). Each baseline session was comprised of 40 transitions between the multiple-schedule components: 10 were lean to lean, 10 were rich to rich, 10 were lean to rich, and 10 were rich to lean. For each subject, there was considerable post-reinforcement (or, pre-ratio) pausing during the rich-to-lean transition, whereas such pausing was minimal during the other three transitions. In subsequent test conditions, a delay was imposed during each of the 40 transitions. Pausing was reduced during the rich-to-lean transitions to levels that resembled the other three transitions, and this result also was replicated. The findings are discussed in terms of both basic behavioral processes and their applied implications. |
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