Association for Behavior Analysis International

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Fourth International Conference; Australia, 2007

Event Details

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Paper Session #12
International Paper Session - Determinants of Behaviour on Schedules
Monday, August 13, 2007
10:30 AM–11:50 AM
L2 Room 2
Area: EAB
Chair: Carlos A. Bruner (National Autonomous University of Mexico)
Sustained Performance in Rats with Extremely Intermittent Reinforcement under Regressive Schedules of Reinforcement.
Domain: Experimental Analysis
IVER H. IVERSEN (University of North Florida)
Abstract: In everyday conditions, humans often work tirelessly for hours without any apparent reinforcement. The purpose of the research was to establish an animal model of such operant performance maintained by highly intermittent reinforcement. Several experiments with food deprived rats explored parameters of leaning schedules of reinforcement. The basic research tool used is called “regressive schedules of reinforcement”. Within each session, the intermittency of reinforcement was gradually decreased. For example, a session might begin with variable-ratio (VR) 100, and then regress to VR 80, VR60, VR40, VR20 and then to continuous reinforcement (CRF). Thus, the reinforcement density would always increase within a session. The schedule values were increased gradually across sessions up to extremely intermittent schedules, such as VR 3000. In all cases, the last schedule segment in a session would be very rich. For example, in one condition, the last schedule segment was a block of chow that was hand delivered by the experimenter when the session ended; in this condition the final schedule was FR 2000 with the only reinforcement being the block of chow. The experiments demonstrate how operant behavior can be maintained by extremely intermittent reinforcement in laboratory conditions.
Observing Responses in Pigeons: Manipulating Complementary Probabilities of Reinforcement and Extinction.
Domain: Experimental Analysis
GERSON YUKIO TOMANARI (University of São Paulo), Luana Tavares Hamilton (University of São Paulo), Joao Ianase Matsumoto (University of São Paulo), Roger Ikemori Yamaguishi (University of São Paulo)
Abstract: Four food-deprived pigeons were given a series of thirty 50-s discrete trials that could end either with response-independent food presentation (TS+) or without food presentation (TS-). At the beginning of each trial, the single response key available in the operant chamber was illuminated with white light. During a trial, pecking the key could change the key color from white to red (when TS-) or green (when TS+) on a 15-s variable-interval schedule. Once produced, the key remained red or green until the end of the trial. In baseline conditions, sessions had TS+ in half of the trials and TS- in the other half (0.5/0.5); trials were randomly presented. In the experimental conditions, the complementary proportions of TS+ and TS- were gradually changed in 0.1 steps (0.6/0.4; 0.7/0.3; 0.8/0.2; 0.9/0.1; 1.0/0.0). For two pigeons, first the proportion of TS+ was increased, and then, after a baseline recovery, the proportion of TS- was increased. For the other two pigeons, the sequence of conditions was reversed. Results showed that intermediate proportions of TS- and TS+ were followed by the maintenance of a high frequency of observing responses, as also recorded in the baseline conditions. Under the conditions in which TS- or TS+ was exclusive, observing responses decreased. Comparing TS+ and TS-, the latter was followed by a faster and more pronounced decrease. Such results may contribute to the understanding of the role of S+ and S- for the maintenance of observing responses.
Acquisition of Observing with and without Preliminary Training.
Domain: Experimental Analysis
CARLOS A. BRUNER (National Autonomous University of Mexico), Taokueneshi Villegas Romero (National Autonomous University of Mexico)
Abstract: Extensive preliminary training may not be strictly necessary to establish observing behavior in rats. By contrast experiments done in our laboratory have shown that complex sequences can be established in rats by direct exposure to the scheduled contingencies. In two different experiments rats were exposed to an observing procedure consisting in a two-lever concurrent schedule. Pressing the left lever produced pellets on a mixed random interval (RI) 8 s extinction schedule, each component lasting 32 and 64 s, respectively. Each press on the right lever produced a 6 s signal, different for each component of the mixed schedule. In the first experiment three naive rats were exposed directly to this procedure. While two rats pressed either lever infrequently over 80 sessions observing was established in only one rat. Hypothesizing that acquisition of responding for food would facilitate observing, in a second experiment three rats each were given the opportunity to earn pellets on either an RI 52 s or RI 6 s for 10 sessions and then directly switched to the observing procedure. Observing was established in all rats after a variable period ranging from two to a maximum of 37 sessions. Thus, high rates of responding and of food reinforcement are sufficient to establish observing.
The Role of Food Deprivation in Schedule-Induced Drinking.
Domain: Experimental Analysis
LAURA ACUNA (National Autonomous University of Mexico), Alicia Roca (National Autonomous University of Mexico), Carlos A. Bruner (National Autonomous University of Mexico)
Abstract: In Schedule-Induced Drinking (SID) experiments water intake increases along with food deprivation. This experiment examined the origin of such relation. Nine rats lived within individual experimental chambers 24/7 with water constantly available. Four 1-hour SID sessions were programmed each day. On each session food was delivered on a 180-s fixed time schedule. On the first session enough food was delivered to keep the rats specified weight. During the other three SID sessions enough pellets were delivered per occasion to complete either 1, 3, or 8 grams. On each of three conditions the rats were kept at 100%, 80%, and 70% of their free feeding weight. During the SID sessions more food was associated with more drinking. Under no deprivation rats drank throughout the day regardless of the SID sessions. Increasing food deprivation produced corresponding increases in water intake during the SID sessions, accompanied by corresponding decreases outside the sessions. These data show that food deprivation increases water intake during SID sessions by decreasing water intake outside the SID session; that is to say, by enhancing the concentration of daily drinking exclusively during the sessions.



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