SEARCH · PubMed Health

Results for “Reinforcement Schedule”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 667 records · Page 37Linked to original sources

PubMedDate not supplied

Bombesin effects on responding maintained by a fixed interval schedule of food reinforcement.

The present experiment examined rats' responding maintained by a fixed interval two-min schedule of food reinforcement following IP injections of bombesin (4, 6, 16, 32 micrograms/kg). The results showed that bombesin's effects were rate dependent where the responses per minute emitted during the early portion of the fixed interval were reduced, but responding during the latter portion was unaffected. Bombesin did not reduce overall session responses per minute, pause after reinforcement, or amount of water consumed in the test chamber. The results are in accord with prior research examining the effects of bombesin and cholecystokinin on operant behavior. Together, the data challenge the notion that bombesin affects food-motivated behavior generally; rather, the results indicate that bombesin's effect may interact with the demands required of the animal for reinforcement.

Animals↗

PubMed1976

Instrumental reactions and food and water intake in medial amygdala rats.

Rats were trained preoperatively to perform instrumental reactions for food and water reward on a continuous reinforcement schedule. Two levers on two opposite sides of the Skinner box were available. Each press of the first lever delivered one drop of water and each press of the second lever - one pellet of solid food. After the electrolytic lesions of the medial part of the amygdaloid complex, rats were hypophagic and hypodipsic. Most of the animals showed, however, only small decreases of total unconditioned daily water and food intake. On the other hand, the instrumental performance was markedly impaired, in particular for water reinforcement. Histological verification showed that lesions were restricted to the amygdaloid complex and involved mainly the ventral part of medial nucleus.

Amygdala↗

PubMed1988

Changes in feeding and foraging patterns as an antipredator defensive strategy: a laboratory simulation using aversive stimulation in a closed economy.

The effects of the risk of electric shock on the meal patterns of rats living in an operant chamber were investigated. Rats could obtain food by working on a response lever that provided reinforcement according to chained fixed-ratio continuous reinforcement schedules that allowed the animals control over meal size. Using a two-compartment operant chamber with a safe nesting area and manipulanda area with a grid floor, shock could be correlated with responding on the schedule. Shocks (less than or equal to 1.25 per hour) were scheduled to occur randomly throughout the day, independent of the rat's behavior. Shock caused a reorganization of meal patterns such that the animals took less frequent but larger meals. This pattern reduced the time the animals spent at risk without compromising caloric balance. Similar changes in feeding pattern were obtained in both hooded and albino rats. Exposure to shock in a separate chamber did not produce these behavioral modifications. The magnitude of shock-induced alterations of meal patterns was greater with chained fixed-ratio 90 continuous reinforcement than with chained fixed-ratio 10 continuous reinforcement. Additionally, the rats seemed to be able to reduce food intake but increase caloric efficiency, such that the reduced food intake did not have deleterious effects on maintenance of body weight. These behavioral modifications reduced the number of shocks received from that which would have been expected if meal pattern changes had not occurred. We suggest that this technique may provide a useful laboratory simulation of the impact that the risk of predation has on foraging behavior.

Animals↗

PubMed1993

Modifying the behavior of the violent patient.

Different behavioral techniques are briefly described for treating the violent patient in a hospital setting. Emphasis is placed on doing a careful assessment of the situation and behavior before attempting a behavioral intervention. It is also emphasized that all staff members involved be adequately trained, otherwise the procedures tend to fail. Techniques include strategies for changing the environment, as well as using relaxation procedures, systematic desensitization, differential reinforcement schedules, token economies, response cost, time out, and social skills training. Multi-component programs are also briefly mentioned. The paper emphasizes that violent behavior can be greatly reduced if approached in a systematic way, using procedures based on sound research methodology.

Behavior Therapy↗

PubMed1997

Lesions of the mediodorsal nucleus of the thalamus and classical eyeblink conditioning under less-than-optimal stimulus conditions: role of partial reinforcement and interstimulus interval.

Rabbits received lesions of the mediodorsal nucleus of the thalamus (MD) or sham lesions and were subjected to classical eyeblink (EB) and heart rate (HR) conditioning. Separate groups of sham and lesioned animals received either 50% or 25% reinforcement with a periorbital shock unconditioned stimulus. Other groups received an interstimulus interval of either 1.0 or 1.5 s. Animals with MD lesions acquired the EB conditioned response (CR) more slowly than sham-lesioned animals with either the 1.5-s ISI or with the 25% reinforcement schedule. The lesions had no significant effect on the HR CR, however. Results suggest that information processed by MD is relayed to the prefrontal cortex and is required for somatomotor response selection under nonoptimal learning conditions.

Animals↗

PubMed2003

A half century of scalloping in the work habits of the United States Congress.

It has been suggested that the work environment of the United States Congress bears similarity to a fixed-interval reinforcement schedule. Consistent with this notion, Weisberg and Waldrop (1972) described a positively accelerating pattern in annual congressional bill production (selected years from 1947 to 1968) that is reminiscent of the scalloped response pattern often attributed to fixed-interval schedules, but their analysis is now dated and does not bear on the functional relations that might yield scalloping. The present study described annual congressional bill production over a period of 52 years and empirically evaluated predictions derived from four hypotheses about the mechanisms that underlie scalloping. Scalloping occurred reliably in every year. The data supported several predictions about congressional productivity based on fixed-interval schedule performance, but did not consistently support any of three alternative accounts. These findings argue for the external validity of schedule-controlled operant behavior as measured in the laboratory. The present analysis also illustrates a largely overlooked role for applied behavior analysis: that of shedding light on the functional properties of behavior in uncontrolled settings of considerable interest to the public.

Efficiency↗

PubMed1980

An investigation of peak shift and behavioral contrast for autoshaped and operant behavior.

Instrumental treadle press and nonreinforced key peck responses were monitored during discrimination training and generalization testing in pigeons on positive and negative reinforcement schedules. In Experiment 1, six pigeons pressed a treadle for food on a multiple variable-interval extinction schedule. In Experiment 2, three pigeons pressed a treadle to avoid shock on a multiple free-operant avoidance extinction schedule. Different color keylights signaled S+ and S- components. Some positive behavioral contrast occurred during discrimination training, but the effect was small. Pecking occurred to the S+ keylight in Experiment 1 but not in Experiment 2. On stimulus generalization tests, all subjects displayed a positive peak shift when pressing the treadle for food or to avoid shock. However, peak shift was not found for nonreinforced "autopecks" on the stimulus key, although an area shift was observed in Experiment 1. This is the first demonstration of peak shift for pigeons pressing treadles and the only reliable demonstration of peak shift when negative reinforcement maintained responding. These results, in combination with previous demonstrations of peak shift for rats pressing levers and pigeons pecking keys, indicate that peak shift is a general by-product of operant discrimination learning, since it occurs across a variety of the organisms, responses, and reinforcers.

Animals↗

PubMed1984

The effect of pentobarbitone on variable-interval performance: analysis in terms of Herrnstein's equation.

Six rats were exposed to a series of variable-interval schedules of reinforcement, each schedule specifying a different reinforcement frequency. The effects of two doses of pentobarbitone (24.16 and 40.27 mumol/kg) upon performance maintained under each schedule were examined. The data were analyzed in terms of the goodness of fit of Herrnstein's (1970) equation. Under control conditions (no injection or injection of vehicle alone) response rate was an increasing negatively accelerated function of reinforcement frequency, the data obtained from each rat conforming closely to Herrnstein's equation. In the presence of pentobarbitone there was a reduction in the value of Rmax (the theoretical maximum response rate) in all six rats. The effect of pentobarbitone upon the value of KH (the reinforcement frequency needed to obtain the half-maximal response rate) differed between animals, the value being increased in some rats and decreased in others. This was shown to reflect a systematic relationship between the baseline value of KH and the change in KH produced by pentobarbitone, high baseline values being associated with reductions, and low baseline values with elevations, in the presence of the drug. The data were also analyzed using conventional rate-dependency analysis. In some animals there was a tendency for lower response rates to be suppressed to a greater degree than higher rates, while the reverse was true in other animals. In general, rate-dependency functions provided poor descriptions of the data obtained from individual subjects.

Animals↗

PubMed1981

Ethanol-amphetamine interaction effects on spontaneous motor activity and fixed-interval responding.

The spontaneous motor activity (SMA) of rats was recorded after injections of saline, d-amphetamine sulfate (0.8 mg/kg), and ethanol (400, 800, 1200, and 1600 mg/kg). Each drug treatment was given separately, and the amphetamine treatment was also combined with each ethanol dose. Ethanol, when injected without amphetamine, produced a dose-related decrement in SMA. Amphetamine, injected without ethanol, produced an increase in SMA. The combination of ethanol at 400 mg/kg with amphetamine potentiated the amphetamine-stimulant effect, but higher doses of ethanol counteracted amphetamine-produced increment in SMA. In a second experiment, similar combinations of ethanol and amphetamine were administered to rats lever-pressing for food pellets under a fixed-interval reinforcement schedule. The effect of amphetamine alone depended on baseline rate and varied among individual rats. Ethanol had a depressant effect on response rates, but combinations of the two drug treatments produced rates that, in most rats, were higher than after any single drug or saline treatment.

Animals↗

PubMed1998

Temporal search as a function of the variability of interfood intervals.

We attempted to determine whether timing theories developed primarily to explain performance in fixed-interval reinforcement schedules are also applicable to variable intervals. Groups of rats were trained in lever boxes on peak procedures with a 30-, 45-, or 60-s interval, or a 30- to 60-s uniform distribution (Experiment 1); a 60-s fixed and 1- to 121-s uniform distribution between and within animals (Experiment 2); and a procedure in which the interval between food and next available food gradually changed from a fixed 60 s to a uniform distribution between 0 and 120 s (Experiment 3). In uniform interval schedules rats made lever responses at particular times since food, as measured by the distribution of food-food intervals, the distribution of postreinforcement pauses, and the mean response rate as a function of time since food. Qualitative features of this performance are described by a multiple-oscillator connectionist theory of timing.

Animals↗

PubMed1984

Time-dependent effects of posttraining intrahippocampal injections of corticosterone on retention of appetitive learning tasks in mice.

In previous studies we suggested that corticosterone may modulate hippocampal functioning during memory formation. To test this assumption, we studied the effects of posttrial administration of corticosterone (1 microgram) injected bilaterally in the hippocampus. The treatment was applied at different time intervals after the learning session and the retention session took place 24 h later. Using appetitive operant conditioning tasks in a Skinner box, we found that the posttrial treatment 1) did not affect the retention of a continuously reinforced schedule, 2) improved the retention of a successive discrimination learning task, and 3) was still effective when given 3 h after the acquisition of this task, but not after 6 h. Taken together, the results suggest that corticosterone modulates the hippocampal mechanisms involved in behavioral suppression during memory formation.

Animals↗

PubMed2006

Dopamine receptor blockade and extinction differentially affect behavioral variability.

Dopamine (DA) neurons respond to unexpected food delivery and are inhibited during the omission of expected reward. DA receptor blockade mimics some, but not all, aspects of non-reward (extinction) conditions. It was therefore of interest to ask whether DA receptor blockade produces extinction-like increases in behavioral variability in addition to its well-known operant response-suppressing effects. In the current experiment, rats were trained drug-free on an operant task in which they pressed on a keyboard. Two of the keys led to food on a continuous reinforcement schedule. Both response rates and behavioral variability were measured. Test day administration of D(1) and D(2) antagonists SCH23390 and raclopride, like extinction, suppressed responding but, unlike extinction, did not lead to an increase in variability.

Analysis of Variance↗

PubMed1992

Choice behavior of fornix-damaged rats in radial maze error-free situations and subsequent learning.

Fornix-damaged, sham-operated, and control rats were placed in a radial eight-arm maze for fixed series of runs with either a 0% or a 100% reinforcement schedule in order to study their choice behavior independently from any learning problem. Subsequently, the ability to learn the radial maze task was examined as a function of the exploratory patterns developed in each error-free situation. The results showed that the continuous absence or presence of food in the radial maze induced two distinct models of exploration in sham-operated and control rats: choice alternation in the absence of food and perseveration in the presence of food. Conversely, this dichotomy did not occur in fornix-damaged rats that run approximately the same number of paths in both error-free situations, but made fewer different path choices in the 0% reinforcement condition and more different path choices in the 100% reinforcement condition than controls. When submitted to the radial maze task, a positive transfer was observed in all groups from the error-free situation in which the rats run more different paths: from the 0% reinforcement situation for controls and from the 100% reinforcement situation for the lesioned rats. These data indicate that damaging the septo-hippocampal pathway modifies spontaneous choice behavior through a different response to specific reinforcement programs but does not prevent the memorization and the transfer of information from error-free to learning situations.

Animals↗

PubMed1988

Color preference in pigeons: stimulus intensity and reinforcement contingency effects in the avoidance of blue stimuli.

In a procedure intended to determine color preference in pigeons (which partially replicated Catania, Owens, & von Lossberg, 1983), two keys were illuminated by different colors drawn from a set of amber, red, green, or blue stimuli; this was followed by the presentation of grain when either of the two colors was pecked. The grain was illuminated alternately across trials with the colors presented on the keys. In Experiment 1 the intensity of the color stimuli used was not equalized, whereas in Experiment 2 the intensity of the colors was equalized. The low preference for blue found in Experiment 1, as measured by differential key pecking, was not found in Experiment 2. The discriminability of the intensity-equalized colors was confirmed in Experiment 2a, in which equal-intensity color discrimination problems were presented. In Experiment 3, as in Catania et al. (1983), a response-independent reinforcement schedule was used, but with intensity-equalized colors. In contrast to Experiment 2, very low preference for blue was found here and in Experiment 4, which used a within-subject procedure. These findings suggest that pigeon color preference may be a function of intensity, but all controlling variables have not as yet been identified.

Animals↗

PubMed1976

Rate dependent drug effects: possible state dependency.

Of 6 rats given extensive experience responding on a fixed-interval reinforcement schedule after injections of 1 mg/kg d-amphetamine, 3 showed significant rate dependent changes in responding when presession saline was substituted for d-amphetamine. Low rates were increased and high rates decreased by the change from d-amphetamine to saline, a result commonly found when d-amphetamine is first introduced. This indicates that rate dependent changes in fixed-interval responding may be state dependent phenomena.

Animals↗

PubMedDate not supplied

The effects of interpolated reinforcement on resistance to extinction in children diagnosed with autism: a preliminary investigation.

Studies on the "interpolation of reinforcement" effect (IRE) suggest that switching from an intermittent (INT) to a continuous (CRF) reinforcement schedule may result in less resistance to extinction than if extinction had followed INT alone. The finding has been examined with both human and animal participants using both free- and restricted-operant research preparations with equivocal results. In the present study, the IRE was examined in four young children diagnosed with autism using a free-operant preparation. Participants were matched into pairs and were exposed, in a counterbalanced order, to extinction following CRF "interpolated" between INT and extinction, and to extinction following INT alone. Resistance to extinction was examined by comparing the number of responses emitted during extinction and the number of sessions required to reach an extinction criterion. Responding may be less resistant to extinction following interpolated CRF reinforcement than following INT alone. Methodological refinements necessary for more conclusively demonstrating the IRE are discussed.

Autistic Disorder↗

PubMed1979

Methadone during pregnancy: assessment of behavioral effects in the rat offspring.

Pregnant rats were administered methadone hydrochloride by gastric intubation. Beginning on day 8 of gestation, a drug group received 5 mg/kg/day; the daily maintenance dose was increased to 10 mg/kg after 4 days with the final dose given on day 22. An intubation control group received sterile water alone on the same gestation days and a nontreated control group was left undisturbed, All experimental and control litters were fostered at birth to untreated mothers, Body weights were low at birth among the methadone offspring but were similar to controls by weaning. During adulthood, offspring were tested on several operant tasks that included acquisition of a lever-pressing response, performance on a variable interval reinforcement schedule, acquisition and performance of an auditory-visual discrimination and response inhibition in a "punishment" paradigm. None of these measures revealed any learning or inhibitory impairments among the methadone-exposed offspring. The major behavioral effect produced by the treatment was a high response output which emerged for each sex in different phases of testing.

Animals↗

PubMed1977

Effects of d-amphetamine and chlordiazepoxide on positive conditioned suppression.

Six rats lever-pressed under a variable-interval 80-sec food reinforcement schedule. After responding had stabilized, an 8-sec tone terminating with food delivery was superimposed on the variable-interval schedule on the average once every five minutes without regard to the animal's behavior. This positive conditioned suppression procedure consistently reduced responding during the pre-food stimulus (tone). Neither d-amphetamine (0.5, 1.0, 2.0 mg/kg) nor chlordiazepoxide (7.5, 15, 30 mg/kg) significantly affected the relative suppression produced by the tone. Instead, both drugs produced generally non-selective effects, similarly affecting response rate in the presence and absence of the tone.

Animals↗