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91.
This study explored the reasons why professors would leave their teaching/ research occupations to begin new careers as administrators. Valence-Instrumentality-Expectancy theory of occupational preference and choice was used as a framework to examine mid-career change among professors and department chairmen at a major university. Data showed that professors' intentions to change careers and become administrators could be explained by the theory. Analyses of job characteristics demonstrated that professors who want a mid-career change are primarily attracted by the power and formal authority vested in the administrative position, while professors who prefer to remain in their career paths do so because of the autonomy it offers.  相似文献   
92.
Although vocational psychologists and sociologists have a long history of researching occupational choice, their theoretical postures have almost always been shaped in light of information on males, with little consideration for females. This article is an addition to others which attempt to correct this shortcoming in the literature. The article reviews the dominant conceptual schemes used to study occupational choice, considers potentially female-specific variables, and provides a typology for the analysis of women's marital-familial statuses and work modes.  相似文献   
93.
Signal detection theory (SDT) allows a bias-free measure of sensitivity, d′, to be simply estimated from discrimination data when certain conditions are met. The computation is not straightforward, however, in several popular discrimination designs, such as two- and four-interval same-different designs and the ABX design. The present tables, derived from the SDT models of Macmillan, Kaplan, and Creelman (1977), make possible the estimation of d’ from these complex discrimination designs.  相似文献   
94.
Switching transients or “glitches” are frequently encountered in signal processing applications involving digital-to-analog (D/A) conversion. A low-cost “deglitching” circuit is described and implemented for the Digital Equipment Corporation AA50 D/A converter option on the PDP-8/e minicomputer. Switching transients were eliminated using a noninverting, unity-gain sample-and-hold circuit (employing Datei System’s SHM-IC-1). Switching transients were reduced to below-noise levels across a wide range of output levels and sampling rates.  相似文献   
95.
96.
Early perceptual selection refers to a sequence of perceptual processing in which attentional selection of stimuli occurs before perceptual processing is complete. By contrast, late perceptual selection refers to a sequence in which all stimuli receive complete perceptual processing before selection takes place. An attempt was made to determine if early selection is possible. Three experiments were conducted in which subjects were presented with arrays containing a variable number of red items and a variable number of black items; all array items were randomly positioned around the circumference of an imaginary circle. The subjects task was to report the number of red items. Response time increased with the number of red items, but was essentially independent of the number of black items. The nature of the red and black items was also varied. When the to-be-attended red items were given “Stroop-like” quality (the symbols that were used were directly inconsistent with the correct response for that trial), mean reaction time was increased compared to a baseline condition; when the to-be-ignored black items were given “Stroop-like” quality, mean reaction time was unaffected. These results imply that the relevant (red) and irrelevant (black) items were processed differentially. We conclude that early selection is possible; late-selection models are not supported.  相似文献   
97.
Selective attention was studied when subjects were required to make either speeded classifications of single stimuli or comparisons of pairs of multidimensional stimuli. Experiment 1 established that subjects were able to attend selectively to form when the irrelevant dimension of size or shading varied in a speeded-classification (card-sorting) task. Experiment 2 confirmed this finding in a discrete-trials task. However, subjects werenot able to filter out irrelevant dimensional disparity in a comparably designed simultaneous-comparison (i.e., “same”-“different”) task. Mean “same” reaction time increased monotonically with increases in disparity between the two stimuli on the irrelevant dimension. Experiment 3 also revealed a monotonie increase in “same” RT as a function of irrelevant disparity in a successive-comparison task. These results were discussed in terms of a normalization model proposed by Dixon and Just (1978) in which it is assumed that a subject equates the two stimuli on the irrelevant dimension before deciding that they are the same along the relevant dimension. It was concluded that: (1) although subjects can efficiently filter out irrelevant disparity in a speeded-classification task, interference due to irrelevant disparity is obtained in the comparison tasks, (2) a common process such as normalization does not necessarily underlie performance in the speeded-classification and comparison tasks, (3) the ability to attend selectively to a stimulus dimension may be task determined as well as stimulus determined, and (4) contrary to the Dixon and Just proposal, normalization of irrelevant disparity occurs in a comparison task, even when the relevant dimension is represented as a separate encoding feature.  相似文献   
98.
Recent experiments have indicated that contrast effects can be obtained with vowels by anchoring a test series with one of the endpoint vowels. These contextual effects cannot be attributed to feature detector fatigue or to the induction of an overt response bias. In the present studies, anchored ABX discrimination functions and signal detection analyses of identification data (before and after anchoring) for an [i]-[I] vowel series were used to demonstrate that [i] and [I] anchoring produce contrast effects by affecting different perceptual mechanisms. The effects of [i] anchoring were to increase within-[i] category sensitivity, while [I] anchoring shifted criterion placements. When vowels were placed in CVC syllables to reduce available auditory memory, there was a significant decrease in the size of the [I]-anchor contrast effects. The magnitude of the [i]-anchor effect was unaffected by the reduction in vowel information available in auditory memory. These results suggest that [i] and [I] anchors affect mechanisms at different levels of processing. The [i] anchoring results may reflect normalization processes in speech perception that operate at an early level of perceptual processing, while the [I] anchoring results represent changes in response criterion mediated by auditory memory for vowel information.  相似文献   
99.
Estimating ability parameters in latent trait models in general, and in the Rasch model in particular is almost always hampered by noise in the data. This noise can be caused by guessing, inattention to easy questions, and other factors which are unrelated to ability. In this study several alternative formulations which attempt to deal with these problems without a reparameterization are tested through a Monte Carlo simulation. It was found that although no one of the tested schemes is uniformly superior to all others, a modified jackknife stood out as the best one in general, it was also super efficient (more efficient than the asymptotically optimal estimator) for tests with forty or fewer items. It is proposed that this sort of jackknifing scheme for estimating ability be considered for practical work.This research was funded through a grant from the Law Enforcement Assistance Administration (78-NI-AX-0047) to the Bureau of Social Science Research, Howard Wainer, Principal Investigator. We would like to thank Ronald Mead, Anne Morgan and James Ramsay for kind, generous, and invaluable help at various stages of the project.  相似文献   
100.
Does varying the spacing of repetitions over intervals as long as 1 week aftect recall? The answer from three experiments is yes. Subjects incidentally processed words repeated within a single list and words repeated in separate lists at list spacings of up to 1 week. Memory was tested by free recall shortly after the second presentations or after retention intervals of up to 1 week. Recall of the words repeated across separate lists conformed to a proportionality rule. When the retention interval is short relative to the spacing intervals, performance is inversely related to spacing. When the retention interval is a large proportion of the spacing intervals, performance is directly related to spacing. Does varying the spacing of repetitions within a single list affect recall after a retention interval of 2 weeks? The answer depends on the processing used while studying the words. Processing that generated interitem associations resulted in a within-list spacing effect even after a 2-week retention interval. Without the interitem associations, the effect was absent after a 1-day retention interval. Most of these findings were explained by examining the changing relationship between the retrieval context and the context stored during study.  相似文献   
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