Stochastic ordering using the latent trait and the sum score in polytomous IRT models

In a restricted class of item response theory (IRT) models for polytomous items the unweighted total score has monotone likelihood ratio (MLR) in the latent trait. MLR implies two stochastic ordering (SO) properties, denoted SOM and SOL, which are both weaker than MLR, but very useful for measurement with IRT models. Therefore, these SO properties are investigated for a broader class of IRT models for which the MLR property does not hold.In this study, first a taxonomy is given for nonparametric and parametric models for polytomous items based on the hierarchical relationship between the models. Next, it is investigated which models have the MLR property and which have the SO properties. It is shown that all models in the taxonomy possess the SOM property. However, counterexamples illustrate that many models do not, in general, possess the even more useful SOL property.Hemker's research was supported by the Netherlands Research Council, Grant 575-67-034. Junker's research was supported in part by the National Institutes of Health, Grant CA54852, and by the National Science Foundation, Grant DMS-94.04438.     

Perceptual differentiation as a source of category effects in object processing: Evidence from naming and object decision

The locus of category effects in picture recognition and naming was examined in two experiments with normal subjects. Subjects carried out object decision (deciding whether the stimulus is a “real” object or not) and naming tasks with pictures of clothing, furniture, fruit, and vegetables. These categories are distinguished by containing either relatively many exemplars with similar perceptual structures (fruit and vegetables;structurally similar categories), or relatively few exemplars with similar perceptual structures (clothing and furniture;structurally dissimilar categories). In Experiment 1, responses to the stimuli from the structurally similar categories were slower than responses to stimuli from the structurally dissimilar categories, and this effect was larger in the naming than in the object decision task. Further, prior object decisions to stimuli from structurally similar categories facilitated their subsequent naming. In Experiment 2, we orthogonally manipulated object decision and naming as prime and target tasks, again with stimuli from the four categories. Category effects, with responses slower to objects from structurally similar categories, were again larger in naming than in object decision, and these category effects in naming were reduced by priming with both naming and object decision. We interpret the data to indicate that category effects in object naming can reflect visually based competition which is reduced by the preactivation of stored structural knowledge for objects.     

Cerebral Anesthetization for Localization of Speech: The Contribution of W. James Gardner

In 1949, the neurologist Juhn Wada reported the first use of a new procedure for determining the localization of speech and language in neurological patients: examination of the effects on speech and language after injecting a barbiturate, sodium amytal, into the internal carotid artery of each hemisphere in succession. By the 1960s, Wada'sIntracarotid Amobarbital Procedure,orIAP,had become the method of choice for identifying the speech-dominant side in one kind of neurological patient, persons with epilepsy who are candidates for surgical resection, and it remains so today. In 1941, however, an American neurosurgeon, W. James Gardner, reported his use of a different anesthetization procedure for speech localization in neurological patients. Instead of injecting sodium amytal through the blood supply, as in the IAP, Gardner injected procaine hydrochloride directly into cortical tissue. In this paper, we provide a brief biography of Gardner. We then discuss his method of cortical anesthetization, the theoretical and empirical background guiding his use of this method and his choice of patients, and, finally, the fate of Gardner's method within the scientific community.     

Neural Network Models and Mechanisms of Strategy Development

The focus of this paper is mechanisms that may be responsible for intellectual and developmental differences in the cognitive strategies of typical and atypical children, including those with mental retardation. The discussion of these mechanisms is based on behavioral experiments on external memory strategies and on a set of neural network models designed for these tasks. Following the review of the external memory research, the rationale for using neural network models, how they have been used in other research, and their specific application to intellectual and developmental differences in external memory, including the results of several simulations, are reviewed. This is followed by a discussion of the mechanisms of intellectual differences and developmental change included in the models and some challenges for this type of modeling. Neural network modeling is discussed as an asset to research on cognitive development.     

Guest editors'' commentary: Japanese socialization research in review

This focus section has presented Japanese research on a variety of socialization agents and contexts, including mothering, fathering, peers and multiple-caretakers in families and institutions. The reader is encouraged to compare the papers, discover the theoretical and applied implications of each study for child development in the reader's own culture, and to pursue collaborations with the outstanding young Japanese contributors. We conclude with brief comments on each of the five articles, discussing their limitations, most significant findings, theoretical importance, and implications for subsequent research.     

Gender, relational role orientation, and affinity for animal rights

Research based mainly on non-national samples reports a greater affinity for animal rights among women than men, and proposes a greater relational role orientation among women that emphasizes caring for others to explain this difference. Using a recent national sample comprised of 11% African American and 89% white American respondents, we find that a relational role orientation fails to account for women’s greater support of animal rights. It does provide minor help in distinguishing animal rights advocates from nonadvocates, but only among women and only on one of two measures of animal rights support. We conclude by proposing women’s structural locations as well as the interplay between these locations and women’s role socialization as alternate explanations for gender differences in affinity for animal rights.