Separability of item and person parameters in response time models

This paper discusses two forms of separability of item and person parameters in the context of response time (RT) models. The first is separate sufficiency: the existence of sufficient statistics for the item (person) parameters that do not depend on the person (item) parameters. The second is ranking independence: the likelihood of the item (person) ranking with respect to RTs does not depend on the person (item) parameters. For each form a theorem stating sufficient conditions, is proved. The two forms of separability are shown to include several (special cases of) models from psychometric and biometric literature. Ranking independence imposes no restrictions on the general distribution form, but on its parametrization. An estimation procedure based upon ranks and pseudolikelihood theory is discussed, as well as the relation of ranking independence to the concept of double monotonicity.I am indebted to Wim van der Linden for bringing Thissen's (1983) paper to my notice, and to Martijn Berger, Frans Tan, and the anonymous reviewers for their constructive comments on earlier drafts of this paper.     

Exploring the set-theoretical structure of objects by additive trees

Arrangements of feature sets that have been proposed to represent qualitative and quantitative variation among objects are shown to generate identical sets of set-symmetric distances. The set-symmetric distances for these feature arrangements can be represented by path lengths in an additive linear tree. Imperfect versions of these feature arrangements are proposed, which also are indistinguishable by the set-symmetric distance model. The distances for the imperfect versions can be represented by path lengths in an additive imperfectly linear tree. When dissimilarities are defined by the more general contrast model and a constant may be added to proximity data, then for both the perfect and imperfect arrangements an additive tree analysis obtains a perfect fit with an imperfectly linear tree. However, in the case of the contrast model also the distinction between the perfect and imperfect arrangements disappears in that also for the perfect arrangements the resulting tree need no longer be linear.The author is grateful to Mathieu Koppen for detailed comments on an earlier version of this article.     

THE ‘VOLATILE’ MARXIAN CONCEPT OF THE DICTATORSHIP OF THE PROLETARIAT

The thesis of this paper is that even some of the most fundamental concepts of Marxism have been used and abused to fit their advocates' purposes. More specifically, the interpretation of the concept of the "dictatorship of the proletariat" has been subject to a dual development. First, the dictatorship of the proletariat has come to denote an increasingly violent regime. Second, the term has been used to refer to a rule exercised by an ever smaller segment of society. This paper seeks to analyze and elucidate this much disputed and frequently misunderstood Marxist concept. In the first part Marx's use of the term is examined. The second section explores how the same concept was explicated in the writings of some of the most important first generation Marxist thinkers and "practitioners" like Engels, Lenin, Kautsky, Bukharin, and Stalin. Following the summary of my findings I attempt to formulate some meaningful generalizations about the usage of the concept by Marxist thinkers.     

Attitudes toward the unconscious

As a keynote to a conference bringing together psychoanalysts and analytical psychologists, this paper addresses different mythic attitudes toward the unconscious, Starting with the caricatures of Oedipus and Narcissus that the author feels Jung and Freud originally projected onto each Other in the course of their quarrel. He moves on to the fairytale-like stories of Perseus and Beauty and the Beast to discover mote complex images of the stance taken in relation to the unconscious by present-day analysts: working within both die Jungian and the Freudian traditions.     

ANALYZING ALERTNESS AMONG PEOPLE WITH PROFOUND MULTIPLE DISABILITIES: IMPLICATIONS FOR PROVISION OF TRAINING

We investigated whether variations in alertness among individuals with profound multiple disabilities affected subsequent responsiveness to training programs. Three experiments were conducted involving 5 people. In Experiment 1, results indicated that alertness of 3 individuals increased with provision of skill-acquisition training programs. Results also indicated no predictive relationship between alertness levels prior to training and subsequent responsiveness to training. Experiment 2 replicated results of Experiment 1 with 2 participants from Experiment 1 and an additional participant. Results of Experiment 2 also indicated that the increased alertness levels accompanying provision of training were not a function of the participants simply being in an inactive environment prior to training. Results of Experiment 3 indicated that alertness of an additional participant increased through provision of another training intervention, involving a systematic preference assessment. Responses during the preference assessment appeared to be unrelated to previously existing alertness levels. These findings suggest the need for caution when considering the withholding of scheduled training because an individual appears to be nonalert.     

运用规则空间模型识别解题中的认知错误

运用规则空间模型识别学生解题中的认知错误,该模型将认知心理学,项目反应理论和数据库的代数理论相结合,将被试的二值反应模式映射为笛卡尔乘积空间的一组序偶,然后计算被试和错误规则在该空间的代表性位置之间的马氏距离,并通过贝叶斯决策准则划分被试的错误类型,根据６４４名中学生对３０个数学题目的反应,识别出其中８６％的学生可以被划分人１８种认知错误类型中。     

THE DOCTRINE OF THE TRINITY AS A MODEL FOR STRUCTURING THE RELATIONS BETWEEN SCIENCE AND THEOLOGY

Abstract. A strategy for deeding systematically with such complex relationships as those between science and theology is presented after a brief overview of the historical record and illustrated in terms of the concept of divinity. The application of that strategy to the title relationships yields a multilogical/multilevel solution which presents certain analogies to or isomorphisms with the doctrine of the Trinity. These concern mainly the multilogical/multilevel character of both conceptualizations and the relational and contextual reasoning required to conceive them. Furthermore, certain characteristics of the doctrine facilitate the dialogue between theologians and scientists on account of their similarity with such scientific concepts as diversity in unity, multiplicity of relationships, nonseparability, and nonclassical logic.     

EFFECTS OF A VOICE OUTPUT COMMUNICATION AID ON INTERACTIONS BETWEEN SUPPORT PERSONNEL AND AN INDIVIDUAL WITH MULTIPLE DISABILITIES

We evaluated a means of increasing staff members' interactions with an individual with multiple disabilities through use of a voice output communication aid (VOCA). When activated, the VOCA allowed the individual to communicate through synthesized speech. Results indicated that staff members interacted with the individual more frequently when she had access to the VOCA, suggesting that VOCAs may represent an alternative to more traditional staff management programs for increasing interactions.     

Contrast and reallocation of extraneous reinforcers as a function of component duration and baseline rate of reinforcement

Four pigeons responded on multiple schedules arranged on a “main” key in a two-key experimental chamber. A constant schedule component was alternated with another component that was varied over conditions. On an extra response key, conjoint schedules of reinforcement that operated in both components were arranged concurrently with the multiple schedule on the main key. On the main key, changes in reinforcement rate in the varied component were inversely related to changes in response rates in the constant component (behavioral contrast). On the extra key, some reinforcers were reallocated between components, depending on the schedules in effect on the main key in the varied component. In the varied component, the obtained rates of reinforcement on the extra key were inversely related to main-key reinforcement rate. In the constant component, extra-key reinforcer rates were positively related to main-key reinforcer rates obtained in the varied component, and were not a function of response rates on the extra key. In two comparisons, the rate at which components alternated and the value of the main-key schedule in the constant component were varied. Consistent with earlier work, long components reduced the extent of contrast. Reductions in contrast as a function of component duration were accompanied by similar reductions in the extent of reinforcer reallocation on the extra key. In the second comparison, lowering the rate of reinforcement in the constant component increased the rate at which extra-key reinforcers were obtained, reduced the extent of reinforcer reallocation, and reduced contrast. Overall, the results are consistent with the suggestion that some contrast effects are due to the changes in extraneous reinforcement during the constant component, and that manipulations of component duration, and manipulations of the rate of reinforcement in the constant component, affect contrast because they influence the extent of extraneous reinforcer real-location.     

Resistance to reinforcement change in multiple and concurrent schedules assessed in transition and at steady state

Behavioral momentum theory relates resistance to change of responding in a multiple-schedule component to the total reinforcement obtained in that component, regardless of how the reinforcers are produced. Four pigeons responded in a series of multiple-schedule conditions in which a variable-interval 40-s schedule arranged reinforcers for pecking in one component and a variable-interval 360-s schedule arranged them in the other. In addition, responses on a second key were reinforced according to variable-interval schedules that were equal in the two components. In different parts of the experiment, responding was disrupted by changing the rate of reinforcement on the second key or by delivering response-independent food during a blackout separating the two components. Consistent with momentum theory, responding on the first key in Part 1 changed more in the component with the lower reinforcement total when it was disrupted by changes in the rate of reinforcement on the second key. However, responding on the second key changed more in the component with the higher reinforcement total. In Parts 2 and 3, responding was disrupted with free food presented during intercomponent blackouts, with extinction (Part 2) or variable-interval 80-s reinforcement (Part 3) arranged on the second key. Here, resistance to change was greater for the component with greater overall reinforcement. Failures of momentum theory to predict short-term differences in resistance to change occurred with disruptors that caused greater change between steady states for the richer component. Consistency of effects across disruptors may yet be found if short-term effects of disruptors are assessed relative to the extent of change observed after prolonged exposure.