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| International Paper Session - Schedules of Reinforcement |
| Sunday, May 25, 2008 |
| 9:00 AM–10:20 AM |
| Barbershop |
| Area: EAB |
| Chair: Dennis J. Hand (Central Michigan University) |
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| The Reinforcing Value of Water in a Schedule-Induced Drinking Situation. |
| Domain: Basic Research |
| JORGE A. RUIZ (Universidad Nacional Autonoma de Mexico), Varsovia Hernandez Eslava (Universidad Nacional Autonoma de Mexico), Carlos A. Bruner (Universidad Nacional Autonoma de Mexico) |
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| Abstract: Previous studies done in our laboratory have shown that Schedule-Induced Drinking (SID) reduces to the water-reinforcement of the water-producing response. The phenomenon occurs because food deprivation reduces home-cage water intake while the subsequent introduction of food during the SID session reestablishes water intake. How reinforcing is water in a typical SID experiment? This question was answered by comparing the reinforcing value of water in a SID experiment with explicit degrees of water deprivation. Lever-pressing by three rats was reinforced with water on a Progressive Ratio 5 schedule after either 21, 11:30, 17:15 or 5:45 hours of direct water deprivation and the maximum ratios completed at each deprivation level were compared to the maximum ratio completed after food deprivation to 80% of the rats free-feeding weight. To replicate a SID procedure free-food was delivered regardless of the type of deprivation on a Random Time 64s schedule. The maximum ratio completed decreased as water deprivation diminished. When the conditions for SID were established by introducing food deprivation, the maximum ratio completed was similar to 5:45 hours of direct water deprivation. It was concluded that in the SID situation the reinforcing value of water is smaller than that produced by direct water deprivation. |
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| Differential Effects of Alternative Food Sources on Schedule-Maintained Responding. |
| Domain: Basic Research |
| RAQUEL ALO (West Virginia University), Kennon A. Lattal (West Virginia University) |
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| Abstract: To investigate how response-dependent and independent food arranged by different schedules interact when the sources of food are the same or different, two experiments included a series of conditions comparing response rates and patterns under VIs (Experiment 1) and DRLs (Experiment 2), when either a VT or a FT was added to that schedule and delivered food at the same hopper or at another one, located at the opposite side of the chamber. In both experiments, VT and FT schedules did not produce systematically different response rates. Additionally, higher response rates were most frequently observed when there was only one source of food. In Experiment 1, response patterns always changed when the sources of food were different, and a negatively accelerated pattern was more frequently observed when response-independent food was arranged by the FT schedule. In Experiment 2, responding was more variable with 2 sources of food. The exposure to FTs produced either linear or positively accelerated responding, while the exposure to the VT produced only linear responding. In conclusion, changes in response rates and patterns seem to be a function of (1) characteristics of the schedules delivering each food and (2) variables affecting the “discriminability” between these schedules. |
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| An Examination of Conjugate Schedules of Reinforcement. |
| Domain: Basic Research |
| KENNETH MACALEESE (University of Nevada, Reno), Patrick M. Ghezzi (University of Nevada, Reno) |
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| Abstract: Conjugate reinforcement schedules are contingency rules that specify that a reinforcer varies proportionally to the rate and/or intensity of responding. This schedule of covariation has been used to study a range of phenomena (Lindsley, 1962 & 1963; Rovee-Collier & Gekoski, 1979) and has been implicated as being "the schedule of nature" (Lindsley cited in Rovee-Collier & Gekoski, 1977). Despite its use in examining other phenomena, little research has been conducted on the schedule parameters as a subject matter in their own right. The current research study presents a conjugate reinforcement methodology that can be used to study schedule parameters in human operant preparations. Data will be presented and described where this methodology has been used to examine fundamental components of the conjugate reinforcement schedule. |
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| Performance in Extreme Multiple Schedules. |
| Domain: Basic Research |
| ANTHONY P. MCLEAN (University of Canterbury), Randolph C. Grace (University of Canterbury), John A. Nevin (University of New Hampshire) |
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| Abstract: Pigeons responded in multiple schedules with session-to-session variability in obtained reinforcer rates constrained, and reinforcer ratios that varied over 4 log units. Results from such procedures are usually analysed by plotting log response ratios against log reinforcer ratios. Treated this way the data revealed a nonlinear relation whereby matching or overmatching occurred with extreme reinforcer ratios, whereas undermatching was found with moderate ones. Although many existing models of multiple-schedule performance can predict a non-linear relation of this form, most are structured similarly to Herrnstein’s equation and these all under-predict performance at the extreme reinforcer ratios. A model for response rate and resistance to change in multiple schedules, by Nevin and colleagues, is structured to reflect response-reducing forces and behavior's resistance to those forces, and provides the best account of these results. |
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