Correspondence analysis and association models constrained by a conditional independence graph

The manner in which the conditional independence graph of a multiway contingency table effects the fitting and interpretation of the Goodman association model (RC) and of correspondence analysis (CA) is considered.Estimation of the row and column scores is presented in this context by developing a unified framework that includes both models. Incorporation of the conditional independence constraints inherent in the graph may lead to equal or additive scores for the corresponding marginal tables, depending on the topology of the graph. An example of doubly additive scores in the analysis of a Burt subtable is given.Thanks are due to anonymous referees who substantially improved the original draft of this paper.     

Acceleration model in the heterogeneous case of the general graded response model

A new model, called acceleration model, is proposed in the framework of the heterogenous case of the graded response model, based on processing functions defined for a finite or enumerable number of steps. The model is expected to be useful in cognitive assessment, as well as in more traditional areas of application of latent trait models. Criteria for evaluating models are proposed, and soundness and robustness of the acceleration model are discussed. Graded response models based on individual choice behavior are also discussed, and criticisms on model selection in terms of fitnesses of models to the data are also given.This research was supported by the Office of Naval Research (N00014-90-J-1456).     

Models for measurement,precision, and the nondichotomization of graded responses

It is common in educational, psychological, and social measurement in general, to collect data in the form of graded responses and then to combine adjacent categories. It has been argued that because the division of the continuum into categories is arbitrary, any model used for analyzing graded responses should accommodate such action. Specifically, Jansen and Roskam (1986) enunciate ajoining assumption which specifies that if two categoriesj andk are combined to form categoryh, then the probability of a response inh should equal the sum of the probabilities of responses inj andk. As a result, they question the use of the Rasch model for graded responses which explicitly prohibits the combining of categories after the data are collected except in more or less degenerate cases. However, the Rasch model is derived from requirements of invariance of comparisons of entities with respect to different instruments, which might include different partitions of the continuum, and is consistent with fundamental measurement. Therefore, there is a strong case that the mathematical implication of the Rasch model should be studied further in order to understand how and why it conflicts with the joining assumption. This paper pursues the mathematics of the Rasch model and establishes, through a special case when the sizes of the categories are equal and when the model is expressed in the multiplicative metric, that its probability distribution reflects the precision with which the data are collected, and that if a pair of categories is collapsed after the data are collected, it no longer reflects the original precision. As a consequence, and not because of a qualitative change in the variable, the joining assumption is destroyed when categories are combined. Implications of the choice between a model which satisfies the joining assumption or one which reflects on the precision of the data collection considered are discussed.     

初中生考试成绩归因模式研究

在广泛调查初中生对考试成绩的归因和情感反应的基础上,根据Ｗｅｉｎｅｒ的动机和情绪的归因理论,提出了初中生对考试成绩归因的假设模式,然后运用协方差结构模型的统计方法对这个假设模型进行了检验．虽然最初模型经ｘ２拟合度检验被拒绝,但经设定探查产生的最终模型较合适地拟合了数据,并部分支持了Ｗｅｉｎｅｒ的归因理论．按照这个模型,努力归因一内源性维度对初中生的自信心、期望、成就动机产生积极的影响．     

Ecosystemic consultation in the kibbutz: social process and narrative in two cases of community “epidemic”

This paper emphasizes working with the social component of the biopsychosocial model. A dual approach for renarrating dysfunctional community narratives and for changing the social process is described. This approach was applied to two cases of epidemics allegedly cased by mysterious environmental agents that occured on kibbutzim. The collective adoption of irrational beliefs is analyzed by using concepts from sociology and crowd psychology. The suggestive effects of the emotional contagion and of the preoccupation with a persistent belief are examined by applying the concept of monoideism. The epidemics were resolved by working in collaboration with the community. The intervention programs mobilized inner resources by helping the kibbutzim to adopt a more unified approach to their presenting problems, and by challenged them to face previously avoided more fundamental dilemmas.     

Moral growth in medical students

Although students bring to medical school a fairly well established value system, the potential for moral growth through the medical school environment and experience is substantial. The educational environment poses a succession of developmental and adaptive tasks to be accomplished. Several of these tasks are discussed here, tasks that are value-laden and involve, directly or indirectly, the interplay of ethical theory and practice. During the past quarter century, the two influences that have had the greatest impact on the moral growth and moral reasoning capacity of medical students have been the incorporation into the medical school curriculum of courses in medical humanities and the admission to medical school of an increasing number of female students. The female students have brought to medical school a level or dimension of moral reasoning (morality as care or responsibility for others) to augment the male students' focus on rights and justice considerations.     

恐惧发生与预防的实验研究：──Ⅰ、强烈噪音下恐具行为的动物模型

通过不同方法对ＳＤ型大鼠分四组进行实验处理,观察比较大鼠的行为,发现：在突然的高强度噪音条件下,大鼠出现恐惧的行为反应;强刺激组大鼠恐惧行为较控制组明显增多,行为的唤醒适应能力异常,并存在显著的个体差异;噪音脱敏训练对提高大鼠在高强噪音条件下的应激能力、减少恐惧具有良好的促进作用;在脱敏训练中尤以逐渐递增噪音强度、刺激时间与平均分配实验日结合的方法效果最为显著。     

Increasing the variability of response sequences in pigeons by adjusting the frequency of switching between two keys.

Three experiments compared the amounts of behavioral variability generated with two reinforcement rules. In Experiments 1 and 2 pigeons received food whenever they generated a sequence of eight pecks, distributed over two keys, provided that the sequence contained a certain number of change-overs between the keys. Although no variability was required-the birds could obtain all reinforcers by repeating the same sequence-the pigeons emitted a large number of different sequences. In Experiment 3 pigeons received food whenever they generated a sequence that had not occurred during the last 25 trials. After prolonged training, the birds showed more sequence variability than in the first two experiments. The analysis of the internal structure of the response sequences revealed that, in general, (a) the location of the first peck was highly stereotyped; (b) as the trial advanced, the probability of switching to the initially preferred key decreased whereas the probability of switching to the other key increased; and (c) a first-order Markov chain model with transition probabilities given by a logistic function accounted well for the internal structure of the birds' response sequences. These findings suggest that, to a large extent, the variability of response sequences is an indirect effect of adjustments in changeover frequency.