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PubMed1975

Effects of d-amphetamine on the behavior of pigeons maintained by a second-order schedule of reinforcement.

The effects of various doses of d-amphetamine were studied on the responding of two pigeons exposed to a second-order schedule of reinforcement. With this schedule, food was presented following the completion of a sequence of three 2-minute fixed-interval components. A visual stimulus was presented at the completion of each fixed interval, including the one which was terminated with food. The pigeons' behavior was characterized by a pause immediately after each stimulus presentation followed by a gradual increase in response rate as the interval progressed. d-Amphetamine was found to increase the low rates of responding which occurred early in each interval and to decrease the high rates of responding at the end of each interval. These effects occurred whether responding preceded the presentation of food or the brief stimulus alone.

Animals↗
PubMed1969

Further observations on overt "mediating" behavior and the discrimination of time.

When the lever-pressing behavior of five rats was maintained by a DRL schedule (reinforcement was scheduled only when a specified waiting time between successive responses was exceeded), collateral behavior developed that apparently served a mediating function. In two cases this behavior did not arise until the experimental environment included pieces of wood that the rats started to nibble. When collateral behavior first appeared, it was always accompanied by an increase in responses spaced far enough apart to earn reinforcement. If collateral behavior was prevented, the number of reinforced responses always decreased. Extinction of lever pressing extinguished the collateral behavior. Adding a limited-hold contingency to the schedule did not extinguish collateral behavior. It appears that the rat can better space its responses appropriately when concurrently performing some overt collateral activity. The amount of this activity apparently comes to serve as a discriminative stimulus. To assume the existence of internal events that serve as discriminative stimuli in temporal discriminations is, at least under some circumstances, unnecessary.

Animals↗
PubMed1994

Japanese high school and college students' responses to the Adolescent Reinforcement Survey Schedule.

Factor-analyzed correlations among items of the Japanese Adolescent Reinforcement Survey Schedule by Japanese high school students (N = 939) and college students (N = 500) were compared to investigate the changes in reinforcers between mid- and late adolescence, gender differences, and the specific groupings of reinforcers which suggest certain interventions for either or both groups of adolescents. The factor analysis yielded ten interpretable factors in both groups. These factors were similar and did not suggest a dramatic shift in reinforcers between mid- and late adolescence. Items related to heterosexual activities and antisocial behaviors were rated as more pleasurable by males and items related to interpersonal relationships and academic activities were rated as more pleasurable by females. Since both groups of students attach high reinforcement value to interpersonal interaction with peers and family members, interventions focusing on social skills development might be popular and well attended.

Adolescent↗
PubMed1974

Induced attack during multiple fixed-ratio, variable-ratio schedules of reinforcement.

TWO PIGEONS WERE EXPOSED TO A MULTIPLE SCHEDULE OF REINFORCEMENT: in the presence of one discriminative stimulus, key pecks produced grain according to a fixed-ratio schedule; in the presence of a second discriminative stimulus, key pecks produced grain according to a variable-ratio schedule. The key-peck requirements in the two components were increased in successive stages from 50 to 125 responses. Live target pigeons were restrained at the rear of the chamber. Attacks against the targets were automatically recorded, and a variety of measures of attack behavior were taken. Attacks, when they occurred, always followed grain presentation. All measures revealed higher levels of attack during the fixed-ratio component at all parameter values. All measures generally increased with increases in fixed-ratio values with both birds, and with increases in variable-ratio values with one bird. With the other bird, only the per cent of reinforcements followed by attack increased with increases in variable-ratio value; all other measures first increased and then decreased. Both increasing and bitonic functions relating induced attack to schedule parameters have been reported in experiments usually employing a single measure of attack. The measures have varied widely among these experiments. It is suggested that further studies of induced attack examine a wider range of schedule parameters and that relationships among measures be studied.

Journal Article↗
PubMedDate not supplied

Effect of cyproheptadine on bar-pressing for food reward in rats.

Lever pressing rate under a continuous reinforcement schedule for food reward in rats was reduced significantly by cyproheptadine in the dose of 5 and 10 mg/kg body weight. Under fixed ratio schedule of reinforcement, the responding was also suppressed significantly by 5 and 10 mg/kg body weight doses of cyproheptadine. However, high dose (20 mg/kg) of cyproheptadine administered subsequent to the low doses, failed to inhibit the bar pressing rate under either continuous or fixed ratio schedules.

Animals↗
PubMed1990

Super-reactivity to amphetamine toxicity induced by schedule of reinforcement.

The chronic exposure of rats to a schedule of operant water reinforcement coupled with chronically restricted access to water sensitized the animals to intermittent d-amphetamine injections (0.31-2.5 mg/kg with intervals of 12-23 days between any two injections) in such a way that this drug came to produce catastrophic losses of body weight (32.4% of control levels). In the sessions when d-amphetamine was administered, the rats were also given a total of 12 brief electric shocks. Loss of body weight was unaccompanied by parallel changes in operant behavior performance, or in food or water intake. Remarkably, in other studies with the same interventions (sham schedule sessions, water deprivation, and foot shocks), with the exception that reinforcers were never delivered, d-amphetamine did not produce catastrophic falls in body weight. This super-reactivity to d-amphetamine toxicity may be mediated by a possible stressor action of the schedule of reinforcement. Its mechanism might be analogous to the known sensitization produced by classical experimental stressor stimuli to the repeated administration of d-amphetamine.

Animals↗
PubMed1986

Allocation of complex, sequential operants on multiple and concurrent schedules of reinforcement.

Pigeons could produce food by pecking exactly four times on each of two keys, in any order. In the first experiment, these response sequences were reinforced on a series of multiple schedules of variable-interval reinforcement. In the second experiment, these response sequences were reinforced on a series of concurrent schedules of reinforcement. In both experiments, highly stereotyped response sequences developed. If these response sequences were treated as individual responses, the resulting data conformed to what is typically reported in studies of multiple and concurrent schedules involving individual responses. For example, behavioral contrast was observed with the multiple schedules, and matching was observed with the concurrent schedules. However, schedule manipulation had no effect on within-sequence characteristics of responses like accuracy, stereotypy, or rate. These data constitute further evidence that response sequences can become functional behavioral units.

Journal Article↗
PubMed1984

Self-control behavior in hyperactive and nonhyperactive children.

This study was aimed at evaluating the self-control behaviors of hyperactive (HA) and nonhyperactive ( NHA ) first-grade pupils under conditions of repeated failure on a previously learned concept formation task. Subjects were divided into HA and NHA groups on the basis of their scores on the Conners (1969) Teacher Rating Scale. During the training stage of the experiment the children learned a concept formation task under a schedule of contingent positive reinforcement. In the test stage they performed the same task but under a negative noncontingent reinforcement schedule. The results revealed no differences in initial rate of learning the task between the groups. After the introduction of the negative noncontingent reinforcement schedule, however, the HA group showed a marked decrease in the use of effective problem-solving strategies. The HA children's performance on the concept formation task was accompanied by the emission of negative self-evaluations and solution-irrelevant statements. The NHA group used significantly more statements showing useful goal-directed cognitive mediations than the HA children. The results suggested that HA children may have deficits in self-control skills.

Attention Deficit Disorder with Hyperactivity↗
PubMed1987

Factor analysis of the Adolescent Reinforcement Survey Schedule (ARSS) with college freshmen.

A factor analysis of the Adolescent Reinforcement Survey Schedule (ARSS) with a male and female college freshman (N = 231) population yielded 10 interpretable factors: Heterosexual Dating, Peer Interaction, Sibling/Family Interaction, Sexual Pleasure, Anti-School/Work, Leisure/Work Activity, Drugs/Acting Out, Entertainment/Social Activity, Home Avoidance, and Romantic Fantasy Activity. The first three factors are similar to a Positive Social interaction factor identified in a study that used the adult form of the Reinforcement Survey Schedule with a male and female college population. Suggestions are made from the ARSS responses of the college freshmen re interventions to facilitate social skill competency and the relationship aspects of sexual activity. A recommendation is made to replicate the current study with groups of early and mid-adolescents in order to study reinforces during different periods of adolescent development.

Adolescent↗
PubMed2002

Comparison of the reinforcing efficacy of two dopamine D2-like receptor agonists in rhesus monkeys using a progressive-ratio schedule of reinforcement.

High-efficacy D2-like dopamine (DA) receptor agonists can function as positive reinforcers when made available to animals for intravenous self-administration under a fixed-ratio (FR) schedule of reinforcement. In a previous study, however, low-efficacy D2-like agonists failed to maintain self-administration under an FR schedule, suggesting that agonist efficacy is directly related to efficacy as a positive reinforcer. To examine this hypothesis further, the present study compared two D2-like DA receptor agonists that maintained FR responding, but differ in their D2-like receptor efficacy and selectivity, using a procedure designed to rank-order drugs according to their efficacy as reinforcers. Rhesus monkeys (n=5) were prepared with chronic, indwelling intravenous catheters and allowed to self-administer cocaine (0.1 mg/kg/injection) or saline on different days under a progressive-ratio (PR) schedule. When responding was stable, doses of the full D2-like agonist R(-)-propylnorapomorphine (NPA) or the partial D2-like agonist R(-)-apomorphine (APO) were made available for self-administration in the test sessions. Both compounds maintained self-administration with sigmoidal or biphasic dose-response functions. Surprisingly, the lower efficacy agonist APO was the more efficacious positive reinforcer. This result fails to support the hypothesis that D2-like receptor efficacy is directly related to efficacy as a reinforcer. It is possible that other pharmacological effects, e.g., D1 receptor activity, influenced self-administration.

Animals↗
PubMed2000

Dissociation in conditioned dopamine release in the nucleus accumbens core and shell in response to cocaine cues and during cocaine-seeking behavior in rats.

The dopaminergic innervation of the nucleus accumbens is generally agreed to mediate the primary reinforcing and locomotor effects of psychostimulants, but there is less consensus on conditioned dopamine (DA) release during drug-seeking behavior. We investigated the neurochemical correlates of drug-seeking behavior under the control of a drug-associated cue [a light conditioned stimulus (CS+)] and to noncontingent presentations of the CS+ in the core and shell subregions of the nucleus accumbens. Rats self-administered cocaine under a continuous reinforcement schedule in which a response on one of two identical levers led to an intravenous cocaine infusion (0.25 mg/infusion) and a 20 sec light CS+. Response requirements for cocaine and the CS+ were then progressively increased until stable responding was established under a second-order schedule of reinforcement. During microdialysis, rats were presented noncontingently with a set of 10 sec CS+ and neutral tone stimuli (CS-) before and after a 90 min period during which they responded for cocaine under a second-order schedule. Results showed the following: (1) nucleus accumbens DA increased in both the core and shell during intravenous cocaine self-administration; (2) noncontingent presentations of a cocaine-associated CS+ led to increased DA release selectively in the nucleus accumbens core; and (3) extracellular DA levels were unaltered in both core and shell during a protracted period of drug-seeking behavior under the control of the same cocaine-associated cue. These results indicate that the mesolimbic dopamine system is activated after exposure to drug-associated stimuli under specific conditions.

Acoustic Stimulation↗
PubMed1974

Peak shift as a function of multiple schedules of reinforcement.

Pigeons were trained to respond to two stimuli on the wavelength continuum, 550 nm and 570 nm, each correlated with an independent schedule of reinforcement. The multiple schedule component in effect during 550 nm (S1) was always a variable-interval 1-min. During the 570-nm stimulus (S2) the second component of the schedule was either variable-interval 30-sec, 1-min, 2-min, 5-min, or extinction for different groups of birds. Generalization gradients were obtained after this training, with the following results: (1) response rate to S1 during training was related to the reinforcement frequency associated with S2; the distribution of responding during generalization testing was a function of the schedules of reinforcement used during training and the response rates they produced. Decreases in the relative frequency of reinforcement correlated with S2 resulted in increases in the distribution shift of responses away from S2 during generalization testing.

Journal Article↗
PubMed1983

Hill-climbing by pigeons.

Pigeons were exposed to two types of concurrent operant-reinforcement schedules in order to determine what choice rules determine behavior on these schedules. In the first set of experiments, concurrent variable-interval, variable-interval schedules, key-peck responses to either of two alternative schedules produced food reinforcement after a random time interval. The frequency of food-reinforcement availability for the two schedules was varied over different ranges for different birds. In the second series of experiments, concurrent variable-ratio, variable-interval schedules, key-peck responses to one schedule produced food reinforcement after a random time interval, whereas food reinforcement occurred for an alternative schedule only after a random number of responses. Results from both experiments showed that pigeons consistently follow a behavioral strategy in which the alternative schedule chosen at any time is the one which offers the highest momentary reinforcement probability (momentary maximizing). The quality of momentary maximizing was somewhat higher and more consistent when both alternative reinforcement schedules were time-based than when one schedule was time-based and the alternative response-count based. Previous attempts to provide evidence for the existence of momentary maximizing were shown to be based upon faulty assumptions about the behavior implied by momentary maximizing and resultant inappropriate measures of behavior.

Journal Article↗
PubMed1970

A comparison of variable-ratio and variable-interval schedules of reinforcement.

Four pigeons responded under a two-component multiple schedule of reinforcement. Responses were reinforced in one component under a variable-ratio schedule and in the other component under a variable-interval schedule. It was found that when rates of reinforcement were equal in the two components, the rate of response in the variable-ratio component was nearly twice that in the variable-interval component. Furthermore, for three of the four subjects, the function relating response rate to relative rate of reinforcement in the variable-ratio component had a slope 2.5 to 3 times the slope of the corresponding function for the variable-interval component.

Journal Article↗
PubMed1973

Operant responding in Siamese fighting fish (Betta splendens) as a function of schedule of reinforcement and visual reinforcers.

Siamese fighting fish were trained to emit an operant response that was reinforced by the opportunity to view a motion picture film image of another fish. Performance under various schedules of reinforcement was examined. When reinforcement followed every response and when reinforcement was delivered after every second response, the number of responses per session was higher than during operant level or during extinction. Reinforcement delivered following intervals of no responding (differential reinforcement of other behavior) markedly decreased responding. Light from a projector without film was found to be as effective a reinforcer as film reinforcement. Responding when projector light reinforcement followed every response was maintained at approximately the same level as that obtained under film reinforcement. Responses per session decreased when only the light was delivered on a differential-reinforcement-of-other-behavior schedule. The behavior of the fish during presentation of the film was markedly different from their behavior while the projector light was being presented.

Animals↗
PubMed1994

Effects of 8-OH-DPAT, 5-CT and muscimol on behaviour maintained by a DRL20 schedule of reinforcement, following microinjection into the dorsal or median raphe nuclei.

Experiments were performed to investigate the effects of microinjections of the 5-HT(1A) agonist 8- hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT), the non-selective 5-HT(1) agonist 5-carboxamidotryptamine (5-CT) and the GABA(A) agonist muscimol into the midbrain raphe nuclei, on behaviour maintained by a differential reinforcement of low rate (DRL) 20 schedule of food reinforcement. Following acquisition of responding under the DRL20 schedule, in which responses were reinforced only if they occurred at least 20s after the previous response, two groups of rats were prepared with a stainless steel guide cannula aimed at either the dorsal raphe nucleus or the median raphe nucleus. Injections of 8-OH-DPAT and 5-CT into the median raphe dose-dependently increased responding and reduced the number of reinforcers earned, leading to a net reduction in response efficiency from 45% to approximately 27% (5µg 8-OH-DPAT) and 22% (375ng 5-CT). Both drugs appeared to shift the frequency distribution of inter-response times (IRTs) towards shorter IRTs, and lowered the mean IRT. These effects were not observed after dorsal raphe injections of either drug. This pattern of results, together with results obtained in other paradigms measuring response inhibition, suggests that suppression of the activity of median raphe 5-HT neurones induces deficits in the ability to withhold responding. Muscimol increased responding, decreased the number of reinforcers earned and reduced response efficiency after both dorsal raphe and median raphe injections. These effects were more pronounced following median raphe injections, and were of considerably greater magnitude than those observed following treatment with the 5-HT agonists. Muscimol injected into the median raphe lowered the mean IRT, and increased the frequency of short duration IRTs. Thus, stimulation of GABA(A) receptors within the median raphe induces a pattern of behavioural disruption in the DRL task, that is more severe than that resulting from selective inhibition of 5-HT neural activity. The effects of muscimol probably arise from a general behavioural activation, rather than a specific deficit in the ability to withhold responding.

Journal Article↗
PubMed1988

The effects of a variety of instructions on human fixed-interval performance.

College students were instructed to press a button for points under a single reinforcement schedule or under a variety of reinforcement schedules. Instructions for a single schedule were either specific or minimal. Instructions on a variety of schedules involved specific instructions on eight different schedules of reinforcement. Subsequent to the varied training, responding under a fixed-interval schedule occurred at a low rate. Both the minimal and specific instruction training led to fixed-interval responding that was similar to the responding exhibited during training. These findings suggest that under certain conditions instructed behavior is sensitive to changes in contingencies.

Journal Article↗