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231.
Robin Giles 《Synthese》1992,90(2):301-343
A generalization of the usual approach to the expected utility theory is given, with the aim of representing the state of belief of an agent who may decline on grounds of ignorance to express a preference between a given pair of acts and would, therefore, be considered irrational from a Bayesian point of view. Taking state, act, and outcome as primitive concepts, a utility function on the outcomes is constructed in the usual way. Each act is represented by a utility-valued function on the states — but not all such functions are taken to represent acts. A weaker than usual set of axioms on preferences between acts is now postulated. It is shown that any agent can be represented by a risk function that assigns to each (mixed) state a number that gives the maximum loss (in utility) the agent might expect should be the actual state of the world. The form of the risk function is determined, both in general and in important particular cases. The results show that any rational agent behaves as though he were acting under the guidance of a set of Bayesian (or, more generally, pseudo-Bayesian) advisors.  相似文献   
232.
Developed and validated instruments for urban and culturally diverse adolescents to assess their self-reported transactions with family, peer, school, and neighborhood microsystems for the constructs of social support, daily hassles, and involvement. The sample of 998 youth were from schools in three Eastern cities with high percentages of economically disadvantaged youth. Data were collected before and after the transition to junior high school or to senior high school. Blacks constituted 26%, whites 26%, and Latinos 37% of the sample. Factor analyses confirmed and enhanced the hypothesized four-factor microsystem factor structure for support, hassles, and involvement; internal consistency and stability coefficients were consistent with these structures. In general, the microsystem factors were common across gender, ethnicity, and age. However, when group differences did occur on these demographic variables, they tended to validate the salience of microsystem specificity. In contrast to the total scores, the microsystem-specific factors yielded more meaningful and differential information with regard to demographic differences and the mediating processes across a school transition.  相似文献   
233.
234.
This paper argues that there is an urgent need for philosophers to convince educationalists of the practical value and the necessity of the philosophical task, particularly analysis. The nature of philosophical analysis is outlined in terms of the criteria of clarity, coherence, completeness and compatibility, which, it is argued, in turn lead to a degree of commonality. The tendency to substitute metaphor or analogy for analysis in argument is then considered, with illustrative reference to the idea of teaching as a craft. In the final section, it is suggested that resort to analogy is merely one example of a more general tendency to distance ourselves from the task of coming to grips with what is actually our field of interest, namely education.  相似文献   
235.
Generally, infants prefer infant-directed (ID) to adult-directed (AD) speech. Mostly, researchers have used unfamiliar female voices in these studies. We investigated preferences for maternal ID speech in 1- and 4-month-olds. Using a procedure in which infants controlled access to voices by fixating a visual display, infants listened to recordings of natural female ID and AD speech. In Experiment 1, 1-month-olds heard recordings of maternal ID and AD speech, but these infants showed no preference for maternal ID speech. In Experiment 2, 1-month-olds heard the same ID and AD speech tapes but were not familiar with the speakers. Contrary to Experiment 1, these infants preferred ID speech. In Experiment 3, 4-month-olds heard recordings of maternal ID and AD speech and showed a significant preference for ID speech. Collectively, these results suggest that infant attention to ID speech depends on both speaker-general and speaker-specific characteristics, with interesting developmental changes occuring during early infancy.  相似文献   
236.
Dichotic listening research with children has continued to be prevalent although numerous authors have described both theoretical and methodological limitations with traditional dichotic listening free-recall paradigms. The present research adds to this growing skepticism by reanalyzing two major longitudinal studies of children's ear asymmetries. These two studies, based in different countries (United States, Holland), utilized highly similar paradigms (free-recall digits), subjects (males), and age levels (kindergarten and second and fifth grade). The questions of ear advantage development, patterns of ear advantages, and the relationship between dichotic listening performance and reading skills are addressed from the multiple statistical methodologies represented in the literature. From these analyses, support for all of the major hypotheses regarding the developmental patterns of dichotic listening performances could be obtained from the same data samples. The use of traditional free-recall dichotic listening paradigms are not recommended for use with children. The implications for future research are discussed.  相似文献   
237.
To determine the relationship between individual exponents for cross-modal stimulus matches for both directions of matching, and to assess the transitivity of individual exponents, subjects were asked to adjust both the judgment and criterion stimuli. Experiment 1 involved four continua paired in 12 ordered combinations; Experiment 2 involved five continua and 20 ordered combinations. Two subjects served in each experiment. The individual exponent of the power function for matches of A to B was close to the inverse of the exponent for matches of B to A, but there was systematic deviation, indicating the presence of a small regression effect. Transitivity of individual exponents was determined by forming ratios of exponents from matches involving other continuum pairs to predict obtained exponents; the means of the distribution of deviations of obtained from predicted values was ?.02 log units, and the standard deviation was .15 log units, indicating that, on the average, predicted values were close to obtained exponents—that is, transitivity of exponents holds for individuals.  相似文献   
238.
In an experiment designed to measure the effects of stimulus overload on altruism, 60 female subjects were randomly assigned to three stimulus conditions of 20 subjects each: (1) overload, (2) overload with perceived control, and (3) no overload. Subjects performed simultaneous proofreading and number attention tasks while at the same time listening to distracting or nondistracting background sound, and one group believed they could have the sound turned off if they desired. Following task performance, all subjects received a request for a favor from an ostensibly unrelated confederate. Although all subjects performed the tasks about equally well regardless of stimulus condition, altruism increased significantly across the three conditions. Results were discussed in terms of stimulus overload associated with the urban environment.  相似文献   
239.
It was hypothesized the mothers' predictions of their caregiving interventions would be differentially influenced by infants' facial expressions of sadness, anger, and physical distress. Mothers viewed slides of infants whose facial displays had first been objectively classified with the Maximally Discriminative Facial Movement Coding System (Izard, 1979). Mothers imagined their infants showing similar expressions while scaling their own tendencies to respond with a number of specific caregiving and socializing interventions and affective reactions. Multivariate ANOVAs showed that the mothers' predictions differed for the three types of negative display. In an emotion decoding task, mothers' responses did not differ as a function of the infants' sex. The patterns of decoded emotions were most similar between physical distress and anger expressions, and least similar between physical distress and sadness expressions. Generally, the findings supported the hypothesis that the negative facial displayes signaled different affective states and had differential motivational effects on the mothers.  相似文献   
240.
The partitioning of squared Eucliean distance between two vectors in M-dimensional space into the sum of squared lengths of vectors in mutually orthogonal subspaces is discussed and applications given to specific cluster analysis problems. Examples of how the partitioning idea can be used to help describe and interpret derived clusters, derive similarity measures for use in cluster analysis, and to design Monte Carlo studies with carefully specified types and magnitudes of differences between the underlying population mean vectors are presented. Most of the example applications presented in this paper involve the clustering of longitudinal data, but their use in cluster analysis need not be limited to this arena.  相似文献   
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