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| Reinforcement Magnitude 1 |
| Sunday, May 30, 2004 |
| 2:30 PM–3:20 PM |
| Commonwealth |
| Area: EAB |
| Chair: Christian Lopez Gutierrez (National Autonomous University of Mexico) |
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| Temporal Control and Response Strength in a Free-Operant Psychophysical Procedure |
| Domain: Applied Research |
| LORI LIEVING (University of Texas Health Sciences Center), Kennon Andy Lattal (West Virginia University) |
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| Abstract: The present experiments examined the relation between timing and response strength. Pigeons responded on a two-component multiple schedule consisting of the free-operant psychophysical procedure, in which trials lasted 50 s. During the first 25 s of each trial, responding on the left key was reinforced and during the second 25 s of each trial, responding on the right key was reinforced. In each experiment, responded was maintained by either rich and lean rates of reinforcement (Experiment 1) or long or short reinforcer durations (Experiment 2). Responding then was disrupted by adding response-independent food delivery during the intertrial interval and by prefeeding. In general, the results were consistent with the existing literature: response rates and ET50’s were more disrupted during the lean components than during the rich components. The effects of the disruptors provided partial support for the Behavioral Theory of Timing (BeT). In addition, during the rich components, time was overestimated relative to estimates of time during the lean components. It is suggested that temporal control and response strength are related in the sense that both measures tend to vary in a manner consistent with predictions based on the BeT and the response strength literature. |
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| Effects of Different Deprivation Levels on the Establishment: Maintenance and Extinction of Leverpressing by Rats |
| Domain: Applied Research |
| CHRISTIAN LOPEZ GUTIERREZ (National Autonomous University of Mexico), Carlos A. Bruner (National Autonomous University of Mexico) |
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| Abstract: Three rats each were kept at 80, 90 or 100% of their free feeding weight and directly exposed during 95 sessions to a fixed-interval 32 s schedule of food reinforcement. Leverpressing was established in all rats. The rats deprived at 80% of their free feeding weight leverpressed at a higher rate than the rats deprived at 100% while the rats deprived at 90% leverpressed at rates indistinguishable from the other two conditions. Once responding was established, scalloped response patterns developed for all rats during the fixed intervals regardless of deprivation level. After the response acquisition phase, holding deprivation levels constant, all rats were exposed to 20 sessions in which leverpressing had no programmed consequences. During extinction, response rate was higher for the rats at the 80% deprivation level than for the rats deprived at 100% of their free feeding weight. The rats at 90% of their weight did not differ from either of the two other deprivation levels. The results were taken to show that food deprivation may not be a crucial condition for neither, the acquisition of a new response or its subsequent maintenance. |
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