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PubMed1998

Experience-Weighted Attraction Learning in Coordination Games: Probability Rules, Heterogeneity, and Time-Variation.

In earlier research we proposed an "experience-weighted attraction (EWA) learning" model for predicting dynamic behavior in economic experiments on multiperson noncooperative normal-form games. We showed that EWA learning model fits significantly better than existing learning models (choice reinforcement and belief-based models) in several different classes of games. The econometric estimation in that research adopted a representative agent approach and assumed that learning parameters are stationary across periods of an experiment. In addition, we used the logit (exponential) probability response function to transform attraction of strategies into choice probability. This paper allows for nonstationary learning parameters, permits two "segments" of players with different parameter values in order to allow for some heterogeneity, and compares the power and logit probability response functions. These specifications are estimated using experimental data from weak-link and median-action coordination games. Results show that players are heterogeneous and that they adjust their learning parameters over time very slightly. Logit probability response functions never fit worse than power functions, and generally fit better. Copyright 1998 Academic Press.

Journal Article↗
PubMed1963

The role of temporal discriminations in the reinforcement of Sidman avoidance behavior.

Animals learn to avoid with the Sidman procedure even though the avoidance response is not followed by the termination of any warning stimulus in the environment. What reinforces this response? The accepted explanation has been that the avoidance response is reinforced when it terminates other behavior that has become aversive by pairing with shock. However, the reinforcement may also be derived from the temporal discriminations that develop with Sidman avoidance. These and other temporal discriminations show that the animal has available some events that vary with the postresponse time. The shock will closely follow the temporal stimuli at long postresponse times and would be expected to make them aversive. The stimuli at short postresponse times would have a relatively low aversiveness due to their more remote relation to shock. Since the avoidance response changes a long postresponse time to a short one, that response would be followed by a decrease in aversiveness which would reinforce it. When sharp temporal discriminations are present, reinforcement from the decrease in aversiveness of temporal stimuli probably plays a dominant role in maintaining the avoidance response. This formulation fits the available data and has adequate answers for the objections that have been raised to earlier conceptions of the role temporal discriminations might play in Sidman avoidance. Although under some conditions the reinforcement in Sidman avoidance seems to be primarily due to the decrease in aversiveness of temporal stimuli, under other conditions there probably is reinforcement from the termination of conditioned aversive responses.

Animals↗
PubMed1993

Some considerations concerning practice and feedback in nursing education.

Dominant approaches to reflective practice and experiential learning in Australia and the United Kingdom seem to reflect a limited view of the functions of practice and feedback in human learning. These functions will be described from a cognitive psychological perspective and the weaknesses of such approaches discussed. It will be argued that Schönian reflective practice and some experiential learning techniques can reinforce rather than eliminate inappropriate action tendencies and that this, in turn, could consolidate nursing's theory-practice gap.

Clinical Competence↗
PubMed2001

Effects of repeated exposure to JP-8 jet fuel vapor on learning of simple and difficult operant tasks by rats.

Groups of 16 Sprague-Dawley rats each were exposed by whole-body inhalation methods to JP-8 jet fuel at the highest vapor concentration without formation of aerosol (1,000 +/- 10% mg/m3); to 50% of this concentration (500 +/- 10% mg/m3); or to treated room air (70 +/- 81 L/min) for 6 h/d, 5 d/wk, for 6 wk (180 h). Although two subjects died of apparent kidney complications during the study, no other change in the health status of exposed rats was observed, including rate of weight gain. Following a 65-d period of rest, rats were evaluated for their capacity to learn and perform a series of operant tasks. These tasks ranged in difficulty from learning of a simple food-reinforced lever pressing response, to learning a task in which subjects were required to emit up to four-response chains of pressing three different levers (e.g., press levers C, R, L, then C). It was shown that repeated exposure to 1,000 mg/m3 JP-8 vapor induced significant deficits in acquisition or performance of moderately difficult or difficult tasks, but not simple learning tasks, as compared to those animals exposed to 500 mg/m3. Learning/performance of complex tasks by the 500-mg/m3 exposure group generally exceeded the performance of control animals, while learning by the 1,000-mg/m3 group was nearly always inferior to controls, indicating possible "neurobehavioral" hormesis. These findings appear consistent with some previously reported data for operant performance following acute exposure to certain hydrocarbon constituents of JP-8 (i.e., toluene, xylenes). There has, however, been little previously published research demonstrating long-term learning effects for repeated hydrocarbon fuel exposures. Examination of regional brain tissues from vapor-exposed rats indicated significant changes in levels of dopamine in the cerebral cortex and DOPAC in the brainstem, measured as long as 180 d postexposure, as compared to controls.

Administration, Inhalation↗
PubMed1990

Expectancies of reinforcer location and quality as cues for a conditional discrimination in pigeons.

Experiment 1 demonstrated that reliably correlating different reinforcer locations (top vs. bottom) with sample stimuli markedly enhanced the performance of White Carneaux pigeons in a spatial conditional discrimination. This differential outcome effect was more evident at longer retention intervals. In Experiment 2, pigeons were given the opportunity to learn about two redundant reinforcer features--location (top vs. bottom) and quality (grain vs. chow). Which reinforcer feature exerted control over choosing depended on task structure. In the congruent task, where pecks to the top key operated the top feeder and pecks to the bottom key operated the bottom feeder, reinforcer location exerted predominant control. In the incongruent task, where pecks to the top key operated the bottom feeder and vice versa, reinforcer quality exerted exclusive control. These results have implications for the nature of reinforcer representations in instrumental learning.

Animals↗
PubMed1985

Ontogenesis of learning: V. Variation in associative and nonassociative control of an operant forelimb response in infant rats.

To study ontogenetic variation in the mechanisms that control operant responding, infant rats 4-16 days old were trained to lift a forelimb in order to receive an infusion of a sucrose-milk solution (reinforcer). Although the learning processes that contribute to this behavior were to some extent functional in pups 5-6 days old (Experiment V), there were major age-related constraints on the performance of this response. We were unable to observe selective responding with the reinforced forelimb until pups were 9 days old (Experiment I). This was in part because pups tested when 7, but not 9 days old, were highly activated (as measured by responding with both forelimbs) by both the reinforcer (Experiment II) and cues associated with the reinforcer during training (Experiment IV). Implications of these findings are discussed.

Age Factors↗
PubMed1995

Effects of reward and response costs on inhibition in ADHD children.

This study examined effects of reward and response costs on the ability of 19 attention-deficit hyperactivity disorder (ADHD) and 17 control children to inhibit responding. Children were tested under 4 reinforcement conditions on a go/no-go learning task developed by J. P. Newman, C. S. Widom, and S. Nathan (1985). Two conditions involved both reward and response costs. 1 response costs only, and 1 reward only. ADHD children made more commission errors than controls across the 4 conditions. Analyses of learning curves indicated that group differences became larger on later trials. Thus, impaired inhibition was more generalized in ADHD children than in the psychopaths and extraverts studied by Newman and colleagues, and it became most evident when the children were required to improve learning across trials.

Attention Deficit Disorder with Hyperactivity↗
PubMed1975

Arousal and learning, and noncontingency detection in one-year-old infants.

The relationship between arousal and learning was studied with 6 infants 1 yr. of age on a two-choice discrimination learning task. The behavioral indices of arousal (activity level) and learning (response rate and reinforcements) correlated significantly (r, .44). Affective state correlated positively with activity level (r, .47) during the learning phase of the experiment. Two control conditions were presented following the learning phase of the experiment. Noncontingent (response independent) reinforcement produced significantly faster response deceleration than nonreinforcement. Affective response did not differ between nonreinforcement and noncontingent reinforcement conditions.

Acoustic Stimulation↗
PubMed1989

The effects of p-chloroamphetamine, a depletor of brain serotonin, on the performance of rats in two types of positively reinforced complex spatial discrimination tasks.

Learning in male Sprague-Dawley rats was assessed in two types of positively reinforced complex spatial discrimination tasks (Stone 14-unit T-maze and eight-arm radial-arm maze) following cytotoxic lesions of central serotonergic terminal projection fields with p-chloroamphetamine (PCA). Learning, as expressed as mean number of errors per day and mean number of trails required to reach criterion, was significantly enhanced in the PCA-lesioned animals trained in the Stone maze. On the other hand, the performance of the PCA-lesioned animals trained in the eight-arm radial-arm maze was not found to differ significantly from that of saline-injected animals. The improved acquisition of the PCA-lesioned rats trained in the Stone maze was completely abolished following pretreatment with the selective serotonergic reuptake inhibitor norzimeldine. Neurochemical analyses of the brains of representative animals revealed that the levels of serotonin and its major metabolite, 5-hydroxy-3-indoleacetic acid, were both significantly reduced by PCA in all regions examined. While it is clear from these and other studies that the serotonergic nervous system plays an important role in the processes underlying learning and memory, these results further underscore the selective role of this neurotransmitter system in the way information is processed by the brain.

Amphetamines↗
PubMed2006

The role of the amygdala and rostral anterior cingulate in encoding expected outcomes during learning.

Successful passive avoidance learning is thought to require the use of learned stimulus-reinforcement associations to guide decision making [Baxter, M.G., Murray, E.A., 2002. The amygdala and reward. Nature Reviews. Neuroscience 3, 563-573]. The current experiment investigated the neural correlates of successful passive avoidance learning in 19 healthy adults. Behaviorally, subjects showed a distinct pattern of performance: early indiscriminate responding to stimuli (pre-criterion performance), followed by relatively rapid learning before a plateau of successful performance (post-criterion performance). Neural responses to post-criterion correct responses were compared with neural responses to both incorrect responses and pre-criterion correct responses. Post-criterion correct responding was associated with increased activation in regions including rostral anterior cingulate, insula, caudate, hippocampal regions, and the amygdala.

Adult↗