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| Topics on the Persistence of Behavior |
| Saturday, May 24, 2008 |
| 3:00 PM–4:20 PM |
| Barbershop |
| Area: EAB; Domain: Basic Research |
| Chair: Christopher A Podlesnik (Utah State University) |
| Abstract: The persistence of behavior in the face of changing conditions has been used to express the effectiveness of particular conditions of reinforcement. The exact procedures used to assess persistence, however, have varied depending on the question of interest and theoretical framework. Four papers in the present symposium use measures of persistence in a variety of interesting ways. Using behavioral-economic analyses, Galuska, Winger, and Woods will report a study examining whether the persistence of cocaine-maintained responding with increasing fixed-ratio schedules is affected by additional response-independent cocaine infusions in rhesus monkeys. Next, Fox and Reilly will report a behavioral history study with rats assessing preference and resistance to disruption between two available but different stimulus contexts. Jimenez-Gomez and Shahan will report a study with pigeons examining how preference and resistance to disruption are affected by equal relative but different absolute rates of concurrently available sources of reinforcement across two contexts. Finally, Podlesnik and Shahan will report a study with rats examining preference for and resistance to extinction within two stimulus contexts presenting varying rates of qualitatively different reinforcers. These four papers exemplify the utility and dynamic nature of the study of persistence. |
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| Persistence of Cocaine Self-administration in Rhesus Monkeys: Assessing the Effects of Response-Independent Infusions using Behavioral Economic Analyses. |
| CHAD M. GALUSKA (College of Charleston), Gail Winger (University of Michigan), James H. Woods (University of Michigan) |
| Abstract: In behavioral economic analyses of drug self-administration, drug consumption is plotted as a function of unit price (response requirement / dose). The rate at which consumption decreases with price increases is termed elasticity and may correspond to abuse liability. In this experiment, three rhesus monkeys self-administered cocaine (0.01 and 0.03 mg/kg/inf) across increasing fixed-ratio (FR) requirements (FR 10-1000). After obtaining a baseline demand curve for cocaine, we assessed the effects of response-independent cocaine infusions on cocaine demand. In addition to the infusions earned by completing the FR schedule, noncontingent infusions (of the same dose) were delivered according to a variable-time (VT) 10-, 5-, or 2-min schedule, across conditions. The results suggest that noncontingent cocaine delivered according to the VT 10-min schedule had little effect on cocaine demand. In the VT 5-min condition, the initial level of cocaine demand decreased relative to baseline, but elasticity of demand was largely unchanged. In the VT 2-min condition, the initial level of demand decreased and the demand curve became more elastic in two of three monkeys. One monkey completely stopped responding during this condition. The results suggest that by degrading the response-reinforcer contingency, demand for cocaine decreased. |
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| Persistent Preference for a Multiple-schedule Component Associated with a Richer History of Reinforcement is Not Accompanied by Greater Resistance to Disruption. |
| ANDREW T. FOX (Central Michigan University), Mark P. Reilly (Central Michigan University) |
| Abstract: Four rats were trained on a two-component multiple schedule in which pressing one of two levers (the food lever) was reinforced according to a variable-interval 60 s (VI 60”) schedule of reinforcement in each component. The components differed only in that the houselight was on during one component and off during the other. Pressing a second lever (the switch lever) resulted in an immediate change from one component to the other. During baseline, all four rats showed at least a slight preference for the light component as long as food reinforcers were still being delivered. Preference for the light component was overridden when the reinforcement rate in the dark component was doubled (three rats) or quadrupled (one rat). After extended exposure to this arrangement, the dark component reverted back to VI 60”. Preference for the dark component continued at a relatively high level for 25 sessions despite the equality of the programmed reinforcement rates. Resistance-to-disruption probes (extinction, prefeeding, concurrent free food) did not yield systematic results either with or without controlling for differences in obtained reinforcement rate. Thus, behavior was not more resistant to disruption in a multiple-schedule component that was preferred due to a richer reinforcement history. |
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| Examining the Relation between Preference and Resistance to Change in Multiple Concurrent Schedules. |
| CORINA JIMENEZ-GOMEZ (Utah State University), Timothy A. Shahan (Utah State University) |
| Abstract: According to behavioral momentum theory, the resistance to change of a behavior is determined by the overall rate of reinforcement delivered in the context in which the behavior occurs. Both resistance to change and preference serve as measures of the underlying strength of a behavior. The relation between preference and resistance to change using multiple concurrent schedules has been found to not always covary. The present experiment aimed at further exploring this issue by varying relative rates of reinforcement across conditions. Pigeons responded on multiple concurrent schedules (Rich component: variable-interval (VI) 20-s VI 40-s schedule, Lean component: VI 40-s VI 80-s schedule). Across conditions, the VI values of the schedules accompanying the VI 40 were made richer or leaner in the Rich and Lean components, respectively. During preference probes, pigeons preferred the VI 40 from the Lean component, whereas responding on the VI 40 from the Rich component showed more resistance to disruption by extinction, pre-session feeding, and free-food during the intercomponent interval. Overall, the relation between preference and resistance to change is not clear. This may be due to the use of preference probes to assess preference. |
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| The Effects of Reinforcer Rate and Type on Preference and Resistance to Change. |
| CHRISTOPHER A PODLESNIK (Utah State University), Timothy A. Shahan (Utah State University) |
| Abstract: Consistent with behavioral momentum theory, previous studies have found that changes in relative reinforcer rate and magnitude systematically affect preference for one stimulus context over another and relative resistance to change within those contexts. The present experiment examined whether changes in relative reinforcer type also affected preference and resistance to extinction. Rats pressed levers in a concurrent-chains procedure for access to food pellets, sweetened-condensed milk, or a sucrose solution in the terminal links. Preference, but not resistance to extinction, changed systematically with changes in relative rate and type of reinforcement. These findings are consistent with previous findings that suggest preference is more sensitive to changes in reinforcement conditions than is resistance to disruption. |
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