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| Within-session Changes in Responding |
| Sunday, May 28, 2006 |
| 9:00 AM–10:20 AM |
| Montreal |
| Area: EAB; Domain: Basic Research |
| Chair: Benjamin L. Lawson (Washington State University) |
| Abstract: The topic of within-session changes in responding continues to receive much empirical and theoretical attention. Some of the more recent exploits from this productive research topic include examinations of within-session changes during sessions of drug self-administration, during pre-ratio pauses and wheel running. Examinations of drug self-administration suggest that variability and behavioral history are important factors that contribute to the regulation of drug taking. Analaysis of within-session changes in drug self-administration studies may also help clarify relationships between variables of behavioral economics. Investigations manipulating pre-ratio pauses suggest roles for predictable up-coming events in determining the relative value of current reinforcement. Investigations in wheel running propose sensitization and dishabituation are crucial process in understanding the within-session changes. The presentation of these investigations together will provide attendees with many ideas for future research and with a better understanding of the factors that contribute to within-session changes in responding. |
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| Behavioral-Economic and Within-Session Analyses of the Effects of Brief Abstinence on Smoking. |
| BENJAMIN P. KOWAL (University of Arkansas for Medical Sciences), Richard Yi (University of Arkansas for Medical Sciences), Kristin M. Gatchalian (University of Arkansas for Medical Sciences), Trent M. Trice (University of Arkansas for Medical Sciences), Warren K. Bickel (University of Arkansas for Medical Sciences) |
| Abstract: The relationship between nicotine deprivation and demand for cigarettes was examined in adult smokers. During 3-hour sessions, 3 puffs on a cigarette were available by completing a fixed number of pulls on a response plunger with requirements ranging from 3 to 6,000 responses. All participants completed the requirements in deprived conditions (i.e., asked not to smoke for 6 hours before the session and required to have a carbon monoxide level at least ½ of baseline) and under normal conditions (i.e., asked to smoke as normal, asked to smoke a cigarette under supervision before the experiment began, and with a carbon monoxide level similar to baseline). Rates of responding decreased rapidly following the first 20 minutes in the deprived conditions. Within-session changes in response rates were relatively flat in the normal conditions. Demand was more inelastic and intensity of demand for cigarettes was greater in deprived conditions than in normal conditions. These differences tended to be greater when only the first 20 minutes of the session were used to estimate elasticity and intensity of demand. Longer durations of abstinence have been reported to decrease demand for cigarettes. Analysis of within-session patterns may be useful in clarifying relationships between variables of behavioral economics (e.g., identifying the point at which abstinence begins to decrease rather than increase measures of demand). |
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| A Parametric and Quantitative Analysis of Within-Session Changes in Ethanol-Reinforced Responding in Rats. |
| ERIC S. MURPHY (University of Alaska, Anchorage), Frances K. McSweeney (Washington State University), Zeljka Jutric (University of Alaska, Anchorage), Ann E. Baxter (University of Alaska, Anchorage) |
| Abstract: The experiment tested the hypothesis that habituation to the reinforcer occurs during sessions of ethanol-reinforced responding in Long-Evans rats. Eight rats responded for 3-s access to a 10% (v/v) ethanol solution during 30 min sessions. Reinforcers were delivered by variable interval schedules that provided programmed rates of reinforcement ranging from 60 to 480 reinforcers per hour. Rates of responding primarily decreased within sessions. The within-session pattern of responding changed with changes in the programmed rate of reinforcement. These response patterns were quantitatively evaluated by McSweeney, Hinson, and Cannon’s (1996) three-parameter sensitization-habituation equation. The parameters reflecting habituation (a & b) increased as a function of increases in the rate of reinforcement, indicating that habituation was higher at higher rates of reinforcement. No systematic changes in the sensitization parameter (c) were observed. These results are consistent with McSweeney, Murphy, and Kowal’s (2005) suggestion that habituation contributes to the regulation of drug-reinforced responding. However, these results are also consistent with alternative hypotheses, such as “satiation” to the reinforcer and motor impairment. |
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| Within-session Changes in the Preratio Pause on Fixed-ratio Schedules of Reinforcement. |
| ADAM DERENNE (University of North Dakota) |
| Abstract: Within-session changes in performances under fixed-ratio schedules of reinforcement were examined in two experiments. In Experiment 1, sessions were of moderate duration (40 ratios), and in Experiment 2, sessions ended after the lesser of 2 hrs 30 min or 10 min without a response. Within-session changes were more evident in the latter case than the former. Marked changes in pause durations were observed during the session that suggest a brief period of initial sensitization to the reinforcer followed by a prolonged period of habituation. The results support the view that preratio pause durations are an index of the efficacy of the reinforcer. The findings are discussed also in relation to more general theories of schedule control. |
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| Are Dishabituation and Sensitization Different Phenomenon? |
| ROBERTA V. WIEDIGER (Washington State University), Benjamin L. Lawson (Washington State University), Benjamin P. Kowal (University of Arkansas for Medical Sciences), Jan-Paul Sambataro (Washington State University), Frances K. McSweeney (Washington State University), Jay Wright (Washington State University) |
| Abstract: Several studies have used wheel running as a reinforcer. In these investigations, rats press a lever to gain access to a wheel for a short duration. One typical finding is that the rate of lever pressing decreases during the session. It is also frequently reported that stimuli presented during the session may increase the rate of lever pressing. These within-session changes in response rates may be explained by changes in the effectiveness of the reinforcer with its repeated presentation, (i.e., habituation and sensitization). However there is a dispute in the literature as to whether an increase in the effectiveness of wheel running is more accurately explained in terms of sensitization or a temporary interruption of habituation (i.e., dishabituation). This experiment tried to resolve this dispute, by introducing a tone at different points in time (i.e., at the beginning of the session, when habituation should be weak; towards the middle of the session, when habituation should be strong) during different wheel running sessions. If dishabituation and sensitization are indeed two different processes, then the tones should produce increases only when they are presented towards the middle of the session. If dishabituation and sensitization are the same phenomenon, then the tone should produce similar increases in responding regardless of when it is presented during the session. |
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