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| Reinforcer Efficacy |
| Tuesday, May 27, 2014 |
| 9:00 AM–10:50 AM |
| W175c (McCormick Place Convention Center) |
| Area: EAB |
| Chair: James S. MacDonall (Fordham University) |
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| Conditioning Taste Aversion: Is It Possible Extinguish Sugar Intake by LiCl Administration? |
| Domain: Basic Research |
| ALMA GABRIELA MARTÍNEZ MORENO (University of Guadalajara), Antonio López Espinoza (University of Guadalajara), Laura Vanesa Santos Solano (University of Guadalajara), Imelda De León López (University of Guadalajara) |
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| Abstract: Lithium chloride (LiCl) is effective unconditioned stimuli in the establishment of conditioned taste aversions (CTA) in the rat. It will be effective to extinguish sugar intake? The present study examined effects of Sugar-LiCl conditioning on subsequent sugar intake. Twenty-four albino rats (three-month-old at the beginning of the experiment) were exposed to free access to food and two bottles (water / 8% sugar solution) for 20 days. Then rats drank a 8% sugar solution for 10 min and were then injected intraperitoneally with LiCl (0.2% body weigth, 0.15 Molar) to produce a learned taste aversion to the sugar for three days. Control rats were injected without LiCl. Food and bottle with water did not available during LiCl administration. Later all rats were exposed to same conditions of initial phase during 20 days. Results showed only a sugar intake decreases in final phase respect to initial phase (p=0.00294). Control rats did not show significance differences in both phases (p=0.99489). The role of procedure, sugar solution and LiCL doses on feeding behavior and sugar-LiCl taste aversion conditioning are discussed. Supported by CONACYT 101314. |
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The Effect of Body Weight on Concurrent Schedule Performance and the Pecking Response With Hens |
| Domain: Basic Research |
| SURREY JACKSON (The University of Waikato), Lewis A. Bizo (The University of Waikato), Therese Mary Foster (The University of Waikato), James McEwan (The University of Waikato) |
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| Abstract: Motivating Operations (MOs) are frequently manipulated (by changing access to commodities and manipulating other variables such as body weight) in order to change responding. Manipulations of body weight have been found to alter behaviour, for example obese and lean rats display differential sensitivity to reinforcers on concurrent schedules of reinforcement. What is not known is the effect that altering MOs may have on the topography of the response related to obtaining the reinforcer. This study has two aims, to investigate the effect of altering body weight on concurrent schedule performance and to investigate the effect that altering body weight may have on the time durations of each component of the hens peck response. Three hens held at 85%--5% were shaped via the method of successive approximations and three via autoshaping to respond for food reinforcers on a touch screen. Analysis of video footage of pecks into individual components (head fixation to beak contact to no movement) showed that the time duration of each component remained stable across both groups. Hens then worked for the same reinforcer under concurrent VI VI schedules with a range of reinforcer ratios with body weight held at 85%--5%, then 95--5%. |
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Understanding Preference Shifts: A Review and Alternate Explanation of Within-Trial Contrast and State-Dependent Valuation |
| Domain: Theory |
| JAMES NICHOLSON MEINDL (The University of Memphis) |
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| Abstract: When a stimulus precedes a less preferred event, preference for that stimulus decreases relative to a stimulus that precedes a more preferred event. Recently, however, it has been demonstrated that when a stimulus follows a less preferred event, that stimulus may become favored over a stimulus that follows a more preferred event. This effect has been investigated under different names -- within-trial contrast and state-dependent valuation--and different models have been proposed to explain the effect. This presentation will provide an overview of the phenomenon and describe the two current models. A third model will then be proposed. This new model explains the phenomenon through an analysis of motivating operations. All three models will then be compared in terms of parsimony and predictive capacity. |
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| The Stay-Switch Model Applies to Qualitatively Different Reinforcers |
| Domain: Basic Research |
| JAMES S. MACDONALL (Fordham University) |
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| Abstract: These experiments show the stay-switch model describes choice responding when using qualitatively different reinforcers, the opportunity to eat, or to run. Because food deprivation is a common establishing operation for both reinforcers, Experiments 1 and 2 determined these two reinforcers would not interact when delivered during the same session. Six rats were trained on progressive ratio schedules for running reinforcement. Following stable the break points they were given 0, 5, 11, 22, 45, and 90 pellets before progressive ratio sessions. Experiment 2 trained them on progressive ratio schedule for food reinforcement. Following stable responding gave 0, 75, 165, 330 675 or 1350 sec of running before progressive ratio sessions. The results of both experiments showed that break points did not change systematically with differing amounts of pre-food or pre-running, indicating the reinforcers did not interact. Experiment 3 trained five different rats on concurrent random-interval random-interval schedules using independent schedule for staying left, switching right, staying right and switching left. The results of the first four conditions are described by the stay switch model with a large bias towards food reinforcement. Consistent with the bias, breakpoints for food reinforcers were 2 to 3 times larger than breakpoints for running reinforcers. |
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