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31.
Human Signal-detection Performance: Effects Of Signal Presentation Probabilities And Reinforcer Distributions 总被引:2,自引:2,他引:0 下载免费PDF全文
University students participated in one of four standard two-choice signal-detection experiments in which signal presentation probability was varied and the reinforcement distribution was held constant and equal. In Experiments 1, 3 and 4, subjects' performance showed a systematic response bias for reporting the stimulus presented least often. Experiments 1 and 4 showed that this effect was reliable with extended training and monetary, rather than point, reinforcement. In Experiment 2, all correct responses were signaled in some way, and this produced the opposite relationship between signal presentation probability and response bias. Experiments 1 and 3 found that explicitly deducting money (intended as punishment) for equal numbers of incorrect responses on each alternative, or varying the obtained overall rate of reinforcement, produced no clear change in response bias. The bias, shown by humans, for reporting the stimulus presented least often remains a challenge for theories of stimulus detection. 相似文献
32.
Mothers of problem and nonproblem toddlers rated videotapes of their own and unfamiliar children's behavior. They classified the behaviors as positive, negative, or neutral, and evaluated the intensity of the positive or negative behaviors. Ratings did not differ by problem status; however, all mothers classified their own children's behavior as less negative than did an independent observer. Mothers also evaluated all children's negative behavior as less aversive than did the observer. Finally, mothers mistakenly classified less of their own children's behavior as negative and more as positive when compared to their biases in classifying unfamiliar children's behavior. 相似文献
33.
Therapists and parents were given vignettes describing the behavioural and emotional difficulties of two nine-year-old children and were asked to rate the importance of a number of possible explanations for such difficulties. Broad agreement was found between parents and therapists, but also there were a number of significant differences. Parents endorsed more child centered explanations and put greater emphasis on physical and developmental factors, while therapists endorsed relationships factors and saw the beliefs of other family members as important. Therapists who were parents showed a pattern of responses that lay between those of parents and non-parent therapists. 相似文献
34.
K. Anthony Edwards 《Journal of applied behavior analysis》1978,11(3):421-429
Weight and height data from two studies were recomputed, and original data were computed using a Weight Index formula that accounts for the interaction of actual weight/height changes in growing children and compares this ratio with that of normed weight/height ratios for equal-aged children. Recomputing the data of one study showed that the Weight Index is a more sensitive procedure for assessing long-term behavioral treatment of obesity for girls than weight alone. Recomputing the data of a second study showed that the Weight Index formula is consistent for boys and girls and is a more sensitive procedure for assessing long-term effects of a variety of medical treatments for obesity than the Ponderal Index or weight alone. Computation of the data for 17 “normal” children in a preschool class showed a zero Weight Index score before and after a six-month interval elapsed without treatment. The procedure may be useful in assessing ponderosity or anorexia over intervals of six months or more with growing children or difference between actual and normed weight over shorter intervals. 相似文献
35.
The performance of pigeons trained to detect differences in the duration of stimuli was analysed using a matching model of signal detection. Two white stimuli, S1 and S2, differing in duration, were arranged with equal probability on the center key of a three-key chamber. S1 was systematically varied from 5 seconds to 25 seconds while S2 remained constant at 30 seconds. On completion of the center-key stimulus, a peck on the center key turned on the two red side keys. A left-key response was "correct" when S1 had been in effect on the center key and a right-key response was "correct" on S2 trials. A correct response produced a 3-second magazine light accompanied intermittently by food. Incorrect responses produced 3-second blackouts. Detection performance was measured under two procedures. In the first, the obtained reinforcement ratio was uncontrolled by allowing the number of food reinforcements obtained for correct left- and right-key responses to vary as the stimuli were changed. In the second procedure, the presentation of food reinforcement was controlled by holding the obtained reinforcement ratio constant. Discriminability changed as a function of stimulus differences under both procedures. No such trend was found in response bias. 相似文献
36.
Concurrent fixed-interval variable-ratio schedules and the matching relation 总被引:5,自引:5,他引:0 下载免费PDF全文
Rider DP 《Journal of the experimental analysis of behavior》1981,36(3):317-328
Five rats responded under concurrent fixed-interval variable-ratio schedules of food reinforcement. Fixed-interval values ranged from 50-seconds to 300-seconds and variable-ratio values ranged from 30 to 360; a five-second changeover delay was in effect throughout the experiment. The relations between reinforcement ratios obtained from the two schedules and the ratios of responses and time spent on the schedules were described by Baum's (1974) generalized matching equation. All subjects undermatched both response and time ratios to reinforcement ratios, and all subjects displayed systematic bias in favor of the variable-ratio schedules. Response ratios undermatched reinforcement ratios less than did time ratios, but response ratios produced greater bias than did time ratios for every subject and for the group as a whole. Local rates of responding were generally higher on the variable-ratio than on the fixed-interval schedules. When responding was maintained by both schedules, a period of no responding on either schedule immediately after fixed-interval reinforcement typically was followed by high-rate responding on the variable-ratio schedule. At short fixed-interval values, when a changeover to the fixed-interval schedule was made, responding usually continued until fixed-interval reinforcement was obtained; at longer values, a changeover back to the variable-ratio schedule usually occurred when fixed-interval reinforcement was not forthcoming within a few seconds, and responding then alternated between the two schedules every few seconds until fixed-interval reinforcement finally was obtained. 相似文献
37.
In a symbolic matching-to-sample task, 6 pigeons obtained food by pecking a red side key when the brighter of two white lights had been presented on the center key and by pecking a green side key when the dimmer of two white lights had been presented on the center key. Across Part 1 and Parts 6 to 10, the delay between sample-stimulus presentation and the availability of the choice keys was varied between 0 s and 25 s. Across Parts 1 to 5, the delay between the emission of a correct choice and the delivery of a reinforcer was varied between 0 s and 30 s. Although increasing both types of delay decreased stimulus discriminability, lengthening the stimulus-choice delay produced a greater decrement in choice accuracy than did lengthening the choice-reinforcer delay. Additionally, the relative reinforcer rate for correct choice was varied across both types of delay. The sensitivity of behavior to the distribution of reinforcers decreased as discriminability decreased under both procedures. These data are consistent with the view, based on the generalized matching law, that sample stimuli and reinforcers interact in their control over remembering. 相似文献
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Developing mice were growth-retarded by underfeeding of their mothers during lactation. Control mothers were well nourished throughout. All offspring were fed ad libitum from weaning till their behaviour was tested in adulthood. The undernourished mice had weight deficits at weaning of 49% compared with controls. Nevertheless, they showed partial catch-up growth thereafter, in that their absolute weight deficits decreased between weaning and adulthood. Social behaviour observations were made on pairs of mice of the same treatment group. Previously undernourished mice were slower to start attacking one another, spent more time near or in contact with one another and did less tail-rattling than their controls. 相似文献