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31.
In two experiments, the effect of an illuminated response key on the acquisition of stimulus control by an airflow stimulus was assessed. In the first experiment, pigeons were given nondifferential training with airflow emerging from behind the response key in one of three conditions of illumination: trained to peck a lighted key, trained to peck an unlighted key with a houselight present, trained to peck a key in total darkness. After 10 days of training on a variable-interval schedule of reinforcement, all subjects were given a generalization test on airflow velocity. The gradients for subjects trained in the dark were sharp, while those for subjects trained in lighted conditions were shallow. In the second experiment, the effect of an irrelevant keylight on the acquisition of an airflow velocity discrimination was assessed. Two groups of pigeons were trained to discriminate two airflow velocities. One group was trained with a lighted response key and the other was trained to peck the response key in total darkness. The dark-trained subjects acquired the discrimination more rapidly. The results demonstrate that the acquisition of stimulus control by airflow with either a differential or nondifferential training procedure can be overshadowed by keylight. 相似文献
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George A. Gescheider John H. Wright Barry J. Weber Bruce M. Kirchner Eric A. Milligan 《Attention, perception & psychophysics》1969,5(1):18-20
Three Ss made judgments of the presence or absence of a burst of 60-cps vibration onthe index fingertip.The probability of S’s reporting the presence of a signal was found to be influenced by signal probability and signal intensity. Mean reaction time for reporting the presence of a signal decreased as a function of signal intensity and signal probability whereas mean reaction time for reporting the absence of a signal increased as a function of signal intensity and signal probability. On trials where no signal was presented mean R T for reporting a signal decreased with increases in the signal probability whereas mean RT for reporting the absence of a signal increased with increases in signal probability. The results were interpreted as support for the hypothesis that S’s decision time was longer the closer on the sensory continuum a particular observation was to his criterion. 相似文献
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K. Blokker S. Bruin J. Bryden I. Houseman C. Okkerse C. Van der Meer A. P. Verkaik 《Knowledge, Technology, and Policy》1990,3(3):76-83
In this article the perspective shifts to the “upstream” end of the agricultural knowledge and information system (AKIS).
Because knowledge policy and strategic decision-making are not the prerogative of the public sector, organizations such as
cooperative unions and multinational companies are included. After considering the influence of the changing environment on
the nature of the AKIS, the role of knowledge management and policy in the emerging knowledge and information market is examined.
Special attention is given to public and private R&D. The article then looks where information technology (IT) fits in and
what considerations determine strategic investment in IT projects and sustained services. Some of the European experiences
with this strategic investment are evaluated. 相似文献
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Edward A. Wasserman Kim Kirkpatrick-Steger Linda J. Van Hamme Irving Biederman 《Psychological science》1993,4(5):336-341
Abstract— Two experiments investigated the role of spatial organisation in the discrimination and generalization of complex visual stimuli by pigeons. In Experiment 1, after pigeons had been trained to discriminate line drawings of four objects, they were tested with novel pictures in which the same component parts of the objects were spatially rearranged. The spatially scrambled pictures led to a dramatic drop in recognition accuracy, hut responding remained above chance. In Experiment 2, pigeons reached a high level of discriminative performance when required to choose among four different spatial arrangements of the same object parts. These results confirm Cerella's (1980) conclusion that pigeons discriminate the component parts of complex visual stimuli, but. unless it is assumed that the scrambling deleted or created emergent features, the results disconfirm his conclusion that spatial organization plays no role in pigeons' picture perception. 相似文献
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Uncertain knowledge about continuous quantities is usually formalized through subjective probability distributions (SPD′s). However, results from past experimental research have often pointed to the rather poor quality of SPD′s. Moreover, previous attempts to improve SPD quality frequently appeared to be only partly successful; overconfidence especially proved to be an exceptionally persistent phenomenon. In the present study, method-induced biases in particular are considered to be responsible for the poor quality of SPD′s, and an alternative means for eliciting uncertain knowledge was designed to meet fundamental quality criteria to a more satisfactory degree. The direct realization of a proper scoring rule in a graphically oriented interactive computer program is one of the central features of this new elicitation technique, ELI. An experiment with 48 subjects was carried out to evaluate ELI performance and to compare it with the performance of (a) an existing elicitation technique and (b) a simple technique that only asks for a best guess and a lower and upper bound. The three techniques were evaluated and compared with respect to their contribution to reliable and valid SPD′s and with respect to their practical usefulness. The results indicated that for ELI the fundamental requirements were realized to a great extent. Furthermore, compared with the two other techniques, ELI performance appeared to be superior. In particular, only with the support of ELI did overconfidence appear to be almost absent. 相似文献