A bayesian procedure for mastery decisions based on multivariate normal test data

A Bayesian framework for making mastery/nonmastery decisions based on multivariate test data is described in this study. Overall, mastery is granted (or denied) if the posterior expected loss associated with such action is smaller than the one incurred by the denial (or grant) of mastery. An explicit form for the cutting contour which separates mastery and nonmastery states in the test score space is given for multivariate normal test scores and for a constant loss ratio. For multiple cutting scores in the true ability space, the test score cutting contour will resemble the boundary defined by multiple test cutting scores when the test reliabilities are reasonably close to unity. For tests with low reliabilities, decisions may very well be based simply on a suitably chosen composite score.This work was performed pursuant to Grant NIE-G-78-0087 with the National Institute of Education, Department of Health, Education, and Welfare, Huynh Huynh, Principal Investigator. Points of view or opinions stated do not necessarily reflect NIE positions or policy and no official endorsement should be inferred. The assistance of Joseph C. Saunders is gratefully acknowledged. The author is indebted to an anonymous referee who pointed out several computational errors in the earlier versions of the paper.     

Reinforcement by an imprinting stimulus versus water on simple schedules in ducklings

Ducklings (5 to 28 days old) were trained to peck a pole on fixed-ratio, fixed-interval, and multiple schedules using brief presentation of an imprinting stimulus as the response-contingent event. Other ducklings of the same age were trained similarly except that reinforcement consisted of access to water. With water reinforcement the typical fixed-ratio (“break-run”), fixed-interval (“scallop”), and multiple schedule response patterns were readily established and consistently maintained. With the imprinting stimulus these schedule effects were inconsistent in some subjects and virtually nonexistent in others, despite extended training. Schedule control with the imprinting stimulus was not improved by the use of a reinforcement signaling procedure which enhances responding reinforced by electrical brain stimulation on intermittent schedules. However, the overall rates of responding and the extinction functions generated after reinforcement with water versus the imprinting stimulus were comparable. These findings imply that control by temporal and discriminative stimuli may be relatively weak when a young organism's behavior is reinforced by presentation of an imprinting stimulus.     

Simultaneous factor analysis of dichotomous variables in several groups

A new method is proposed for a simultaneous factor analysis of dichotomous responses from several groups of individuals. The method makes it possible to compare factor loading pattern, factor variances and covariances, and factor means over groups. The method uses information from first and second order proportions and estimates the model by generalized least-squares. Hypotheses regarding different degrees of invariance over groups may be evaluated by a large-sample chi-square test.The research of the first author was supported partly by the Bank of Sweden Tercentenary Foundation under project Structural Equation Models in the Social Sciences, project director Karl G. Jöreskog, and partly by the Swedish Research Council in the Humanistic and Social Sciences under project Analysis of Contingency Tables, project director Bengt Muthén.     

Additive conjoint isotonic probabilistic models (ADISOP)

The ISOP-model or model of twodimensional or bi-isotonicity (Scheiblechner, 1995) postulates that the probabilities of ordered response categories increase isotonically in the order of subject ability and item easiness. Adding a conventional cancellation axiom for the factors of subjects and items gives the ADISOP model where the c.d.f.s of response categories are functions of an additive item and subject parameter and an ordinal category parameter. Extending cancellation to the interactions of subjects and categories as well as of items and categories (independence axiom of the category factor from the subject and item factor) gives the CADISOP model (completely additive model) in which the parallel c.d.f.s are functions of the sum of subject, item and category parameters. The CADISOP model is very close to the unidimensional version of the polytomous Rasch model with the logistic item/category characteristic(s) replaced by nonparametric axioms and statistics. The axioms, representation theorems and algorithms for model fitting of the additive models are presented.     

Biases in Visual Attention in Children and Adolescents With Clinical Anxiety and Mixed Anxiety-Depression

Recent research has indicated that anxious adult and child patients and high trait-anxious adults selectively shift attention toward threatening stimuli. The present study extends this research and investigates the content-specificity of the effects in clinically anxious and mixed anxious–depressed children and adolescents. Twenty four generally anxious patients, aged 9 to 18, 19 mixed anxious–depressed patients, and 24 normal controls were comparable with respect to age, sex, verbal IQ, and vocabulary level. The participants carried out an attentional deployment task in which probe detection latency data were used to determine the distribution of visual attention for threat-related and depression-related material. The results showed that clinically anxious children, relative to controls, selectively allocated processing resources toward threat stimuli. However, mixed anxious–depressed children, relative to controls, did not show any attentional bias towards either threat- or depression-related stimuli. Preliminary data on age and gender differences are also presented. The results of this study are discussed in the light of previous research.     

Development of Sustained Attention Assessed Using the Continuous Performance Test among Children 6–15 Years of Age

The Continuous Performance Test (CPT) is a widely used measure of sustained attention, which may rely on the efficiency of cognitive inhibition. We examined the relationships of age and sex with CPT performance among 341 randomly selected school children 6–15 years of age. Multiple regression analyses revealed that the hit rate, false alarm rate, and sensitivity of both the undegraded and the degraded CPT were associated with age by a quadratic relationship. The age–development curves for the hit rate and sensitivity were convex, whereas that for the false alarm rate was concave. Sex was associated with the hit rate and sensitivity on the degraded CPT only. Our findings are consistent with the hypothesis that sustained attention develops during the primary school ages. The data reported are essential for identifying children with conditions associated with sustained attention deficit, such as attention-deficit hyperactivity disorder, as well as those at an increased risk for developing schizophrenia.     

Perceptual Learning

The extent of adult improvement in not only complex but also simple perceptual tasks is remarkable. Although this phenomenon has been noted and studied since the middle of the 19th century, recent advances in the study of brain physiology and anatomy afford new insights. Improvement specificity suggests that changes involve early sensory cortical areas, previously thought to lose their plasticity following the first years. The critical role of selective attention, even in learning the simplest tasks, as well as the precedence of learning easy cases, suggests the involvement of high-level cortical areas. Learning easy cases is more general than learning difficult cases. This pattern suggests the involvement of both high- and low-level areas in an orderly manner, with easy learning beginning at high-level areas and harder cases being resolved by access to low-level areas. The mapping of behavioral findings to underlying brain sites provides a unified framework for this interdisciplinary field.     

Principles and Problems in the Assessment of Quality of Life in Health Care

A remarkable surge in efforts to assess the quality of life of patients has occurred in recent years in medical research. Philosophical discussions of these developments have focused, on the one hand, on epistemological reservations about the plausibility of measuring quality of life and, on the other hand, on moral and ethical qualms about the meaning of life conveyed in such assessments. Whilst providing an important note of caution, such critiques fail to recognise two basic principles of quality of life in medical research. Firstly it is intended to provide understanding about groups and categories of patients rather than individuals. Secondly the purpose of such research is to produce generalisations about the relative costs and benefits of specific health care interventions rather than absolute judgements regarding the quality of life of patients per se. Selecting a good quality of life measure for a clinical trial requires balancing criteria such as validity with practical feasibility. Such measures will play an increasingly central role in providing research evidence to improve health care.     

关于短时记忆中范畴群集的定位实验

本研究通过对短时记忆的编码或提取阶段进行注意分散来探讨范畴群集的定位问题。以大学生为被试,应用双作业进行分散注意条件下的记忆实验,并与集中注意条件下的记忆实验进行比较。识记材料均为双范畴词表。结果表现无论在编码还是提取阶段分散注意,都导致范畴群集程度的降低。实验结果不支持认为范畴群集的组织过程仅仅发生在记忆信息加工的某一个阶段的看法,而有利于双重定位观点,即认为范畴群集既与编码阶段有关,也与提取阶段有关。     

爬行与婴儿共同注意能力的发展

本研究考察了８～１１个月婴儿共同注意能力的发展趋势以及爬行与其发展的关系。结果表明：１）一岁以内的婴儿在共同注意时有仅跟视相同方向与准确定位他人注视点两种不同水平的表现,这两种表现具有不同的发展趋势;２）影响婴儿共同注意时仅跟视相同方向水平发展的主要因素是婴儿的年龄,爬行时间的效应不显著;３）对婴儿准确定位的发展而言,影响其发展的重要因素是婴儿的爬行而不是婴儿的年龄。