The Client Is the Most Important Common Factor: Clients' Self-Healing Capacities and Psychotherapy

I first briefly review the dodo bird verdict and suggest that we should be responding to it by looking for a new way to conceptualize how therapy works. Then I describe the dominant medical or treatment model of psychotherapy and how it puts the client in the position of a dependent variable who is operated on by supposedly potent therapeutic techniques. Next I argue that the data do not fit with this model. An alternative model is that the client is the most important common factor and that it is clients' self-healing capacities which make therapy work. I then argue that therapy has two phases—the involvement phase and the learning phase—and that the involvement phase is the most important. I next review the five learning opportunities provided by therapy. Finally, I argue that a relational model of therapy focused on consultation, collaboration, and dialogue is better than a treatment model.     

中小学生认知能力发展水平测验的研究

以皮亚杰的认知发展理论为基础,采用皮亚杰及其学生研究认知发展时的任务为测验题目,编制成测量中小学生认知能力发展水平的测验.通过对2240名中小学生施测,结果表明本测验不仅具有很好的信度和效度,而且也具有适中的难度.然后以一所中学特长班学生为被试,通过对他们进行测量,并将测验结果与同年级普通班学生的认知成绩进行比较,结果存在很明显的差异.最后对中小学生认知能力发展水平测量问题进行了探讨.     

多层线性模型在纵向研究中的运用

纵向研究中传统统计技术主要是重复测量的方差分析和多元回归分析，但是这两种技术存在一些局限性，不能合理而充分地解释纵向研究资料。近年来出现的多层线性模型能够更有效地利用纵向数据。为促进多层线性模型在纵向研究中的运用，简要论述了传统统计技术的局限，介绍了多层线性模型的原理及其在纵向研究中的作用，以一组模拟数据为例对多层线性模型中各种参数在纵向研究中的含义进行了详细讨论，对于纵向研究中运用多层线性模型时须注意的问题提出了建议。     

Infants' formation and use of categories to segregate objects

Four- and-a-half-month-old infants' (N = 100) category formation and use was studied in a series of five experiments. For each experiment, the test events featured a display composed of a cylinder and a box. Previous research showed that this display is not clearly parsed as a single unit or as two separate units by infants of this age. Immediately prior to testing, infants were shown a set of category exemplars. Knowledge about this category could help infants disambiguate the test display, which contained a novel exemplar of this category. Clear interpretation of the test display as composed of two separate units (as indicated by infants' longer looking at the move-together than at the move-apart test event) was taken as evidence of category formation and use. In Experiments 1 and 5, infants' prior experience with a set of three different boxes that were similar to the test box facilitated their segregation of the test display. Experiment 2 showed that three different exemplars are necessary: prior experience with any two of the three boxes used in Experiment 1 did not facilitate infants' segregation of the test display. Experiment 3 showed that variability in the exemplar set is necessary: prior experience with three identical boxes did not facilitate infants' segregation of the test display. Experiment 4 showed that under these conditions of very brief prior exposure, similarity between the exemplar set and test box is necessary: prior experience with three different boxes that were not very similar to the test box did not facilitate infants' segregation of the test display. Together, these findings suggest that: (a) number of exemplars, variability, and similarity in the exemplar set are important for infants' category formation, and (b) infants use their category knowledge to determine the boundaries of the objects in a display.     

Tailoring Cognitive Behavioral Therapy for Individuals Diagnosed with Bulimia Nervosa

There is a wealth of data indicating the effectiveness of cognitive behavioral therapy in the treatment of bulimia nervosa. However, the best evidence indicates a treatment success rate of 50%. The purpose of this paper is to briefly describe cognitive behavioral treatment of bulimia nervosa and to offer suggestions on how this therapy approach may be tailored to best serve the needs of individual clients. Such tailoring should ultimately lead to even greater treatment success.     

Representation and working memory in early arithmetic

Working memory has been implicated in the early acquisition of arithmetic skill, but the relations among different components of working memory, performance on different types of arithmetic problems, and development have not been explored. Preschool and Grade 1 children completed measures of phonological, visual-spatial, and central executive working memory, as well as nonverbal and verbal arithmetic problems, some of which included irrelevant information. For preschool children, accuracy was higher on nonverbal problems than on verbal problems, and the best and only unique predictor of performance on the standard nonverbal problems was visual-spatial working memory. This finding is consistent with the view that most preschoolers use a mental model for arithmetic that requires visual-spatial working memory. For Grade 1 children, performance was equivalent on nonverbal and verbal problems, and phonological working memory was the best predictor of performance on standard verbal problems. For both age groups, problems with added irrelevant information were substantially more difficult than standard problems, and in some cases measures of the central executive predicted performance. Assessing performance on different components of working memory in conjunction with different types of arithmetic problems provided new insights into the developing relations between working memory and how children do arithmetic.     

The Meaning vs. The Medical Model in the Empirically Supported Treatment Program: A Consideration of The Empirical Evidence

A review of the debate on the Empirically Supported Treatment Program is presented. It is argued that underlying the specifics of the debate are fundamentally incompatible paradigms: a meaning vs. a medical model. The findings from two gold standard multi-site studies are reviewed to conclude that the control condition meets requirements for an empirically supported treatment. The empirical finding of the failure of clinical training to improve treatment outcomes is explained by the focus on rational factors in training. It is recommended that training of therapists focus on enhancing experiential capacity rather than mastery of manualized treatment approaches.     

On the existence and uniqueness of JML estimates for the partial credit model

A necessary and sufficient condition is given in this paper for the existence and uniqueness of the maximum likelihood (the so-called joint maximum likelihood) estimate of the parameters of the Partial Credit Model. This condition is stated in terms of a structural property of the pattern of the data matrix that can be easily verified on the basis of a simple iterative procedure. The result is proved by using an argument of Haberman (1977). The author wishes to thank the Editor and the anonymous reviewers for their comments that helped to substantially improve the final version of this paper. This research was supported in part by a MURST grant (ex 60%).     

Checking the Assumptions of Rasch's Model for Speed Tests

Two new tests for a model for the response times on pure speed tests by Rasch (1960) are proposed. The model is based on the assumption that the test response times are approximately gamma distributed, with known index parameters and unknown rate parameters. The rate parameters are decomposed in a subject ability parameter and a test difficulty parameter. By treating the ability as a gamma distributed random variable, maximum marginal likelihood (MML) estimators for the test difficulty parameters and the parameters of the ability distribution are easily derived. Also the model tests proposed here pertain to the framework of MML. Two tests or modification indices are proposed. The first one is focused on the assumption of local stochastic independence, the second one on the assumption of the test characteristic functions. The tests are based on Lagrange multiplier statistics, and can therefore be computed using the parameter estimates under the null model. Therefore, model violations for all items and pairs of items can be assessed as a by-product of one single estimation run. Power studies and applications to real data are included as numerical examples.     

Fitting Psychometric Models with Methods Based on Automatic Differentiation

Quantitative psychology is concerned with the development and application of mathematical models in the behavioral sciences. Over time, models have become more complex, a consequence of the increasing complexity of research designs and experimental data, which is also a consequence of the utility of mathematical models in the science. As models have become more elaborate, the problems of estimating them have become increasingly challenging. This paper gives an introduction to a computing tool called automatic differentiation that is useful in calculating derivatives needed to estimate a model. As its name implies, automatic differentiation works in a routine way to produce derivatives accurately and quickly. Because so many features of model development require derivatives, the method has considerable potential in psychometric work. This paper reviews several examples to demonstrate how the methodology can be applied. From the Presidential Address delivered at the 70th Annual Meeting of the Psychometric Society, Tilburg University, The Netherlands, July 5–8, 2005.