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941.
942.
Matching with a trio of concurrent variable-interval schedules of reinforcement 总被引:5,自引:4,他引:1 下载免费PDF全文
A trio of concurrent variable-interval schedules of reinforcement was arranged according to a changeover-key procedure, including a changeover delay of 1.5 sec. The three schedules provided a combined maximum reinforcement rate of 45 reinforcements per hour. With that restriction, the nine experimental conditions included several combinations of variable-interval schedules, sometimes including extinction. The pigeons matched relative response rate and relative time to relative reinforcement rate. Relative time appeared to match some-what better than relative response rate. Performance adjusted rapidly from one experimental condition to the next, whether the change involved two or all three schedules of the concurrent trio. 相似文献
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944.
This paper presents a new methodological approach to classical Pavlovian investigations. Using a yoked group for stimulus pairing trial pacing, behavioral occurrence frequencies, sequential behavior patterns, and behavioral change dynamics are analyzed for rats in both a non-discriminative and a general setting discrimination paradigm. Theoretical issues addressed by a variety of new dependent measures are discussed, and a special emphasis is placed on comparing instrumental and classical procedures as viewed from the behavioral perspective of the subject. 相似文献
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947.
A circuit that uses electroluminescent lamps as light sources for the study of critical flicker fusion (CFF) and apparent motion phenomena is described. The technique involves the modulation of a 2- KH z exciting current with a multivibrator-formed pulse adjustable over a suitable range of frequencies. Components are readily available from commercial sources. 相似文献
948.
949.
Justine R. Schmidt Paul T. Brown Alison M. Waycott 《British Journal of Guidance & Counselling》1988,16(2):113-128
Two bodies of literature on life skills and on family therapy have developed from different sources but have interesting similarities. Life skills comes from training and educational thinking, and concentrates upon the skills of and strategies for coping. Family therapy focuses upon the disturbance of an individual as symbolic of the dynamics of the family, but has at its roots a more-or-less explicit model of what constitutes an effective family, where the interactions can be readily understood in life-skill terms. The two approaches are compared and contrasted. 相似文献
950.
Eight young (average age 20.4 years) and eight elderly (average age 64.4 years) observers took part in three experiments designed to study age-related changes in peripheral retinal function. A further eight young (average age 22.3 years) and eight elderly (average age 63.8 years) observers took part in a replication of experiment 3. All observers had normal or better-than-normal visual acuity and no evidence of ocular pathology. All testing was monocular and the eye with better visual acuity was used. In the first experiment contrast sensitivity was measured in central retina and 10 deg temporally, at spatial frequencies of 0.2, 0.8, 2.0, and 5.0 cycles deg-1. Young observers had better contrast sensitivities than older observers, but only at higher spatial frequencies (2.0 and 5.0 cycles deg-1). For both groups, contrast sensitivity was poorer with peripheral presentation of stimuli than with central presentation, but not for the lowest spatial frequency used (0.2 cycle deg-1). In the second experiment observers had to detect the presence of a sharp edge (square-wave luminance profile), while in the third and fourth experiments the target was a "fuzzy' edge (sine-wave profile). Edges were again presented centrally or 10 deg temporally. As expected from the data of experiment 1, young observers were better able to detect the sharp edge than were the older observers in both central and peripheral viewing conditions. For both age groups, edge detection was better during central viewing than during peripheral viewing. However, contrary to expectations based on the results of experiment 1, detection of the fuzzy edge was better for central than for peripheral viewing for both age groups in experiments 3 and 4. The apparent (and expected) equality of performance found in experiment 3 for young and elderly observers in detecting the fuzzy edge was shown to be due to the range of contrast values used. When appropriate contrast values were used in experiment 4, young observers detected fuzzy edges presented in central retina better than did elderly observers. The results of experiment 1 show sparing of the ability to process low spatial frequencies across (i) age and (ii) retinal location, and are discussed in terms of the notion of (i) models of age-related loss of visual function and (ii) cortical magnification. The results of experiments 2, 3, and 4 provide some support for the proposition that the contrast sensitivity of observers may be used to predict their performance on other visual tasks.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献