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| Choice |
| Sunday, May 29, 2005 |
| 10:30 AM–11:50 AM |
| Boulevard C (2nd floor) |
| Area: EAB |
| Chair: Angel Jimenez (University of Guadalajara, Mexico) |
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| Choice, Changeover Requirements, Haloperidol, and Magnitude of Reinforcement |
| Domain: Basic Research |
| CARLOS F. APARICIO (University of Guadalajara, Mexico) |
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| Abstract: Our research has shown that haloperidol alters response allocation, but it does not take away the reinforcing value of food reinforcers. In three experiments the present study assessed the generality of these findings in dynamic reinforcing environments. Experiment 1 arranged seven ratios of reinforcer to occur in two levers within the same session, Experiment 2 used the same situation to manipulate the changeover requirement, and Experiment 3 varied the magnitude of reinforcement independently of the reinforcer ratio. After several sessions where rats responded for food reinforcers in these situations, four doses of haloperidol (.04, .08, .16, and .24 mg/kg) were assessed (ip) over periods of 12 days. Haloperidol did not impede the rats’ adaptation to the dynamic environment, nor did it interfere with the discrimination they established between rich and lean alternatives. Response distributions changed as a function of magnitude of reinforcement, but were not affected by low doses of haloperidol. High doses of haloperidol suppressed the behavior of switching from one lever to the other; however, none of the doses extinguished lever pressing for food. A reinforcer by reinforcer analysis showed that sensitivity to reinforcement (the slope of the generalized matching law) increased with increasing doses of Haloperidol. The implications of these results for the general anhedonia model will be discussed. |
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| Changeover Requirement in Standard and Forced Choice Situations |
| Domain: Basic Research |
| ANGEL JIMENEZ (University of Guadalajara, Mexico), Carlos F. Aparicio (University of Guadalajara, Mexico) |
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| Abstract: Research has shown that standard and forced choice situations produce similar results when a small changeover requirement is used to separate the reinforcement contingencies in concurrent variable interval-variable interval schedules. This finding was tested in two experiments that manipulated the changeover requirement in dynamic environments. Rats responded for food in two levers that differed in the probability of reinforcement, defining seven ratios of reinforcer that changed seven times within sessions. To switch from the lean to the rich lever, a changeover lever required 1, 8, 16, 24, 32, 40, 48, 56, and 64 responses. For some rats, the contingencies of reinforcement in one lever were independent of those scheduled for the other lever. A forced choice situation was implemented with a different group of rats. The results showed that sensitivity to reinforcement increased with increasing changeover requirement. In the forced choice situation, however, response and time sensitivities were higher than those obtained in the standard situation. The role of the changeover requirement in forced choice situations will be discussed. |
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| Does the Concatenated Generalized Matching Law Include the Necessary and Sufficient Conditions of Reinforcement for Influencing Preference? |
| Domain: Basic Research |
| JAMES S. MACDONALL (Fordham University) |
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| Abstract: The concatenated generalized matching law (CGML) says preference is a function of the allocation of obtained reinforcer rates, magnitudes, immediacies and qualities. In concurrent choice, the rates of earning reinforcers, the number of reinforcers earned (arranged) while at an alternative – the sum of the reinforcers earned for staying at and for switching from an alternative, divided by the time at the alternative, influences preference (MacDonall, 2004). In this experiment I varied, independently, the rates of earning reinforcers and the rates of obtaining reinforcers by using two pairs of random-interval schedules to arrange reinforcers for staying at and switching from each alternative (MacDonall, 2000). In each of six rats I found 1) these procedures can produce data consistent with the CGML, 2) conditions that produced preferences but no difference in obtained rates reinforcer allocation, that is, different obtained rates of reinforcer allocation were not a necessary condition for preference, and 3) conditions that produced differences in the obtained rates of reinforcer allocation but no preference, that is, different rates of reinforcer allocation were not a sufficient condition for preference. The generalized matching law did not describe these results but including rates of earning reinforcers in the CGML described these results. |
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