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Results 351 - 400 of 1343
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Shahan Timothy A - - 2003
Observing responses produce contact with discriminative stimuli and have been considered analogous to attending. Many studies have examined the effects of reinforcement rate on the resistance to change of simple operant behavior, but nothing is known about the resistance to change of observing. Two experiments examined the effects of primary ...
McDevitt Margaret A - - 2003
Pigeons were trained on multiple schedules that provided concurrent reinforcement in each of two components. In Experiment 1, one component consisted of a variable-interval (VI) 40-s schedule presented with a VI 20-s schedule, and the other a VI 40-s schedule presented with a VI 80-s schedule. After extended training, probe ...
Mazur James E. - - 2003
Pigeons responded on a concurrent-chains schedule with two equal variable-interval (VI) schedules as initial links and delays to food of 3 and 12s as the two terminal links. In even-numbered sessions, no other reinforcement schedule was present, and all pigeons showed a strong preference for the response key that had ...
Witkin Jeffrey M - - 2004
RATIONALE: Effects of compounds on punished responding have been predictive of anxiolytic efficacy in humans. The use of mice in these tests has been limited, but the utility of this species in drug discovery and for neurobiological inquiry would benefit from a rapid, reliable method. OBJECTIVES: The present experiments were ...
Bizarro L - - 2003
RATIONALE: The effects of drugs on performance of tasks used to assess attention might be confounded with changes in motivation. Few studies have investigated the role of motivational factors in such situations. OBJECTIVES: To determine how changes in motivation for food influence performance of the 5-choice serial reaction time task ...
Kirby Michael - - 2003
The effects of rapid-eye movement sleep deprivation (REMSD) in rats were studied in relation to variable-interval (VI) reinforcement schedule value. Initially, lever pressing was maintained on a VI 30-s schedule of food pellet delivery. After a baseline was established, rats were repeatedly exposed to 96 hr of REMSD and control ...
Grace Randolph C - - 2003
We report two experiments using a concurrent-chains procedure in which one terminal-link schedule was fixed-interval 8 s and the alternative schedule changed randomly from day to day. In Experiment 1, the alternative schedule varied between 4 s and 16 s according to a pseudorandom binary sequence similar to the one ...
Spring Bonnie B Department of Psychology, University of Illinois Chicago, Chicago, IL, USA. - - 2003
Discontinuing nicotine intake usually results in weight gain partially due to heightened energy intake from between-meal snacks. This experiment tested the hypothesis that the reinforcing value of palatable carbohydrate-rich snacks increases for female smokers during nicotine deprivation. Eighteen smokers and 18 nonsmokers completed a concurrent-schedules operant computer task on two ...
Weatherly Jeffrey N. - - 2003
Research has demonstrated that rats increase their rate of lever pressing for sucrose reinforcement when food-pellet reinforcement will soon be available within the session. Recent results suggest that this increase occurs because stimuli in the session come to signal different levels of overall reinforcement. The present experiment tested this idea ...
Grace Randolph C. - - 2003
Eight pigeons responded in a multiple variable-interval (VI) schedule in which a constant component always delivered 40rft/h, and an alternated component was either rich (200rft/h) or lean (6.67rft/h) in different conditions. Four tests of resistance to change were conducted in each condition: prefeeding, full extinction, constant-component-only extinction, and response-independent food. ...
Doughty Adam H - - 2003
Key pecking of three pigeons was maintained in separate components of a multiple schedule by either immediate reinforcement (i.e., tandem variable-time fixed-interval schedule) or unsignalled delayed reinforcement (i.e., tandem variable-interval fixed-time schedule). The relative rate of food delivery was equal across components, and this absolute rate differed across conditions. Immediate ...
Adriani Walter - - 2003
Human adolescents may have experience with easily available psychoactive drugs. Impulsivity and/or peculiarities in reward systems may play a role. These variables were studied in adolescent (Postnatal Day [PND] 30-49) and adult (PND > 60) CD-1 mice. In Experiment 1 (impulsivity), food-restricted mice were tested in operant chambers with 2 ...
Green Leonard - - 2003
Pigeons were studied on a two-component multiple schedule in which the required operant was, in different conditions, biologically relevant (i.e., key pecking) or nonbiologically relevant (i.e., treadle pressing). Responding was reinforced on a variable-interval (VI) 2-min schedule in both components. In separate phases, additional food was delivered on a variable-time ...
Weatherly Jeffrey N. - - 2003
The present study investigated whether rats' responding for liquid-sucrose reinforcement delivered by a progressive-ratio (PR) schedule would be altered by the addition of food-pellet reinforcement available subsequent to the PR schedule. In Experiment 1, six rats lever pressed for 1% sucrose reinforcers delivered by a PR 3 schedule. In Experiment ...
Erofeev A I - - 2003
Operant activity was studied in monkeys in a situation in which they actively initiated a frequency of pressing a lever to obtain subsequent food reinforcement. Studies addressed the dynamics of relearning when the duration of the lever holding time needed to obtain reinforcement was increased from 1 to 2.5 sec. ...
Francis Ellie L - - 2003
PURPOSE: Accommodation and vergence both appear to be influenced by multiple nonsensory factors. "Effort-to-see" is one of these factors. This study was designed to assess the extent to which effort-to-see affects accommodation and vergence. METHOD: Nine volunteers participated in this study. Stimuli were chosen to stimulate selectively either accommodation or ...
Goddard Murray J - - 2003
Three experiments with rats examined the effects of preexposure to an unconditioned stimulus (US; a single food pellet) on the subsequent ability of that US to effectively signal the delivery of three food pellets during a US-US conditioning procedure. In Experiment 1, latent inhibition (LI) rats showed attenuated conditioning, compared ...
Blair C A J - - 2003
In two experiments, rats received preexposure to three compound flavor stimuli, AX, BX, and CX, where X represents a saline solution. AX and BX were presented in alternation; CX, on a separate block of trials. The value of X was then modified, being devalued by aversive conditioning in Experiment 1, ...
Salamone J D JD Division of Behavioral Neuroscience, Dept. of Psychology, University of Connecticut, Storrs, Connecticut 06269-1020, USA. - - 2003
For several decades, it has been suggested that dopamine (DA), especially in nucleus accumbens, mediates the primary reinforcing characteristics of natural stimuli such as food, as well as drugs of abuse. Yet, several fundamental aspects of primary food reinforcement, motivation, and appetite are left intact after interference with accumbens DA ...
Pérez-Padilla Angeles - - 2003
RATIONALE: d-Amphetamine has been reported to increase schedule-induced drinking punished by lick-dependent signalled delays in food delivery. This might reflect a drug-behaviour interaction dependent on the type of punisher, because no such effect has been found when drinking was reduced by lick-contingent electric shocks. However, the anti-punishment effect of amphetamine ...
Negus S Stevens - - 2003
The present study describes a procedure that permits rapid assessment of environmental and pharmacological factors that may influence the choice between cocaine and food in rhesus monkeys. Daily 2 h sessions were divided into five components. During each component, monkeys (N=4) chose between i.v. cocaine (0-0.1 mg/kg/injection) and food (0, ...
Hackenberg Timothy D - - 2003
Four pigeons were exposed to a token-based self-control procedure with stimulus lights serving as token reinforcers. Smaller-reinforcer choices produced one token immediately; larger-reinforcer choices produced three tokens following a delay. Each token could be exchanged for 2-s access to food during a signaled exchange period each trial. The main variables ...
Frolov A G - - 2003
The possibility that hindlimb movements (elevations) evoked by stimulation of the corresponding contralateral area of the motor cortex could be instrumentalized by reinforcement with food was demonstrated, contradicting some previously published data. Operant movements (interstimulus voluntary high elevations of the hindlimb) were acquired as a result of consistent combinations: cortical ...
Weatherly Jeffrey N - - 2003
Previous research has demonstrated that rats will increase their rates of lever pressing for sucrose rewards in the first half of an experimental session when food pellets, rather than the same sucrose, continually serve as the reward in the second half of the session. This effect has been coined induction, ...
Epstein Leonard H - - 2003
Eating is influenced by both the hedonic preferences and reinforcing value of food. Incentive salience theory predicts these are separate influences. This study tested whether hedonics reliably change as a function of increasing the reinforcing value of food by deprivation in 17 non-obese, non-dietary restrained females. Baseline measures of hedonics ...
Kirkpatrick Kimberly - - 2003
In one experiment, the rate and pattern of responding (head entry into the food cup) under different distributions of intervals between food deliveries were examined. Separate groups of rats received fixed-time (45, 90, 180, or 360 sec), random-time (45, 90, 180, or 360 sec), or tandem fixed-time (45 or 90 ...
Dickinson Anthony - - 2003
Rats were trained on a biconditional discrimination in which the delivery of a food pellet stimulus signalled that pressing on one of two levers would be reinforced, whereas the delivery of a sucrose solution stimulus signalled that the reward was contingent on pressing the other lever. The outcome was the ...
Pinkston Jonathan W - - 2003
A 2-part study with pigeons investigated the role of an explicit operant contingency in determining how cocaine interacts with locomotor activity. In Part 1, pigeons pecked on a fixed-ratio-20 schedule of food presentation. In Part 2, different pigeons were studied without opportunity to peck for food. After determination of cocaine's ...
Killeen Peter R - - 2003
Hungry pigeons received food periodically, signaled by the onset of a keylight. Key pecks aborted the feeding. Subjects responded for thousands of trials, despite the contingent nonreinforcement, with varying probability as the intertrial interval was varied. Hazard functions showed the dominant tendency to be perseveration in responding and not responding. ...
Dixon Mark R - - 2003
We investigated the effects of a concurrent physical therapy activity (keeping the hand open) during delays to reinforcement in an adult man with acquired brain injuries. Once a relatively stable level of hand-open behavior was obtained, the participant was asked to choose between a small immediate reinforcer and a larger ...
Kahng SungWoo - - 2003
Escape (termination of a meal) and token-based differential reinforcement of alternative behavior were used as reinforcement to increase acceptance of food. Using a changing criterion design, the number of bites accepted and consumed was gradually increased to 15 bites per meal. These data suggest that, in some cases, escape may ...
Simmons Jason N - - 2003
The purpose of this study was to evaluate the immediate and subsequent effects of fixed-time (FT) food presentations on mouthing. The effects of FT food presentations were analyzed within a three-component multiple schedule in which baseline conditions were implemented during the first and third components and treatment conditions were implemented ...
Young Robert J - - 2003
Many experiments report that animals will work (lever press) for food in the presence of freely available identical food. This phenomenon has attracted the attention of applied ethologists because it seems to prove that animals have a need to express appetitive behavior. If this is the case, then it has ...
Dawson Jennifer E - - 2003
We used the high-probability (high-p) instructional sequence with and without escape extinction in the treatment of food refusal. Acceptance increased and refusal decreased only with the introduction of escape extinction. These results raise important questions about the high-p sequence in the treatment of food refusal.
Piazza Cathleen C - - 2003
We compared the effects of positive reinforcement alone, escape extinction alone, and positive reinforcement with escape extinction in the treatment of the food and fluid refusal of 4 children who had been diagnosed with a pediatric feeding disorder. Consumption did not increase when positive reinforcement was implemented alone. By contrast, ...
Salamone John D - - 2002
Although the Skinnerian 'Empirical Law of Effect' does not directly consider the fundamental properties of stimuli that enable them to act as reinforcers, such considerations are critical for determining if nucleus accumbens dopamine systems mediate reinforcement processes. Researchers who have attempted to identify the critical characteristics of reinforcing stimuli or ...
Weatherly Jeffrey N - - 2002
Rats' rates of leverpressing for low-concentration liquid-sucrose reinforcers in the first half of an experimental session increase when food pellet, rather than sucrose, reinforcers will be available in the second half. Experiment 1 determined that this induction effect was the outcome of food pellet reinforcement's increasing response rates, not of ...
Chu Lucy - - 2002
Testosterone is essential for copulation, and contributes to sexual motivation. In addition, castrated males are fatter and less active, suggesting that androgens may play a role in non-sexual behaviors, including food-related responses. To test this hypothesis, male hamsters were trained with a cost/benefit test, which compares operant responding for more-preferred ...
Pearce John M - - 2002
In two experiments pigeons received a complex negative patterning discrimination, using autoshaping, in which food was made available after three stimuli if they were presented alone (A, B, C), or in pairs (AB, AC, BC), but not when they were all presented together (ABC). Subjects also received a positive patterning ...
Honey R C - - 2002
Rats were placed in 4 contexts (A, B, C, D) where they received 2 auditory stimuli (X, Y); in A and B, presentations of X were paired with food and those of Y were not, and in C and D, Y was paired with food and X was not. Rats ...
Dickinson Anthony - - 2002
In two experiments, we examined the relative susceptibility to outcome devaluation of lever pressing by rats for either a 10% ethanol solution or food pellets. The rats were trained to press different levers for these two reinforcers using a sucrose-substitution procedure. An aversion was then conditioned from either the ethanol ...
Nock Matthew K - - 2002
A multiple-baseline design was used to evaluate the effectiveness of a behavioral treatment program using modeling, graduated exposure, and contingency management to treat food phobia in a 4-year-old boy. In addition, a treatment component involving time-out and re-introduction of the initial request to consume the target food was added to ...
Nader Michael A - - 2002
RATIONALE: Environmental context has been shown to influence responding under multiple schedules of food reinforcement and to modify the behavioral effects of drugs. However, no systematic study has been conducted under conditions of cocaine self-administration. The hypothesis was that changes in the magnitude of food reinforcement would affect cocaine-maintained response ...
Evenden John - - 2002
RATIONALE: Psychosis and psychotomimetic drugs result in a disorganisation of the structure of thought and behaviour. Normalising these is one of the objects of antipsychotic therapy, and methods for predicting such a therapeutic effect would be of value. OBJECTIVE: The effects of a number of psychotomimetic agents were examined on ...
Comer Sandra D - - 2002
RATIONALE:. Previous studies have shown that buprenorphine differentially suppresses the reinforcing effects of different drugs (cocaine, alfentanil), drug versus nondrug reinforcers (food, drug), and the same reinforcer (food) maintained under different schedules of reinforcement. OBJECTIVES: The purpose of the present study was to determine whether buprenorphine (0.03, 0.1, 0.3 mg/kg) ...
Panlilio Leigh V - - 2003
RATIONALE: Animal models of relapse to drug abuse typically assess the ability of various manipulations to reinstate responding that has ceased due to non-reinforcement (extinction). However, there is a lack of information concerning the reinstatement of responding that has ceased for reasons other than extinction. OBJECTIVES: This study examined the ...
Kamyshev N G - - 2002
This article presents results obtained from studies of the plasticity of changes in social behavior in Drosophila (interactions between individuals in groups) in conditions of homo- and heterogeneous environments. This is the first report of data illustrating self-starting acquisition by female Drosophila of a classical conditioned reflex to contextual factors ...
Carelli Regina M - - 2002
Numerous investigations indicate that the nucleus accumbens (Acb) is an important neural substrate mediating the reinforcing properties of 'natural' rewards (food or water) as well as abused substances. Here, our electrophysiological studies that examined Acb cell firing within seconds of lever press responding for intravenous cocaine vs. water or food ...
Stout Steven C - - 2002
The reinforcement-omission effect (ROE), also known as frustration effect, refers to greater response strength immediately after nonreinforcement (N) than reinforcement (R). The ROE was traditionally interpreted as transient invigoration after N induced by primary frustration. Pigeons demonstrate similar ROEs whether outcomes are surprising (partial R) or expected (discrimination training) in ...
Thorpe Christina M. - - 2002
In time-place learning tasks food availability depends upon both spatial and temporal variables. For example, food might be first available at location one, then location two, then location three, and finally location four. To date, the duration of food availability at each of the locations have been identical (e.g. for ...
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