THE VISUAL SYSTEM'S MEASUREMENT OF INVARIANTS NEED NOT ITSELF BE INVARIANT

Abstract— When two shapes that differ in orientation or size have to be compared or objects have to be recognized from different viewpoints, the response time and error rate art systematically affected by the size of the geometric difference. In this report, we argue that these effects are not necessarily solid evidence for the use of mental transformations and against the use of invariants by the visual system. We report an experiment in which observers were asked to give affine-invariant coordinates of a point located in an affine frame defined by three other points. The angle subtended by the coordinate axes and the ratio of the lengths of their unit vectors systematically affected the measurement errors. This finding demonstrates that the visual system's measurement of invariants need not itself be invariant.     

Philosophy of medicine in the Netherlands

This report explores the relationship between philosophy and medicine in the Netherlands. In Section 1 we outline the ups and downs of medico-philosophical research in our country: pre-war flourishing, post-war decline, and modern renaissance. In Section 2 we review recent Dutch literature in the philosophy of medicine. The topics dealt with include methodology of medical science, alternative medicine, the basic concepts of medicine, anthropological medicine, medicalization, medicine and culture, and health care ethics.     

Meaning,amount of processing,and memory for words

Two experiments were carried out in order to try to resolve the controversy about whether the semantic processing of a word necessarily involves all the elements of its meaning. In the first experiment, subjects categorized a list of auditorially presented words according to whether or not they were natural consumable solids (e.g., “apple“). They were then given an unexpected test of their ability to recall the whole list, which contained equal numbers of words with none, one, two, or all three of the target components. The results confirmed the prediction that the greater the number of components a word has in common with a target category, the better it will be recalled. The second experiment used a visual presentation of a list of words, which subjects scanned for members of a particular target category. There were four different target categories assigned to independent groups of subjects. The results again confirmed the prediction. On the assumption that memorability in such tasks is determined by amount of processing, we conclude that some elements of the meaning of a word can be processed without having to process all of them.     

A new computational method to fit the weighted euclidean distance model

This paper describes a computational method for weighted euclidean distance scaling which combines aspects of an analytic solution with an approach using loss functions. We justify this new method by giving a simplified treatment of the algebraic properties of a transformed version of the weighted distance model. The new algorithm is much faster than INDSCAL yet less arbitrary than other analytic procedures. The procedure, which we call SUMSCAL (subjectivemetricscaling), gives essentially the same solutions as INDSCAL for two moderate-size data sets tested.Comments by J. Douglas Carroll and J. B. Kruskal have been very helpful in preparing this paper.     

An information processing system for the psychiatric emergency room

An information processing system for a psychiatric emergency room is described. Several studies are presented that show the utility of the system. In the first study, variables involved in diagnosis are explicated. The second study attempts to determine the characteristics that distinguish recidivists from nonrecidivists at an emergency room. The third study attempts to find patient variables related to success in short-term treatment programs. The final study is aimed at discovering whether there are psychopathological effects related to the use of inhalants. Together, these studies show the potential of a mental health information system for learning more about the nature of mental disorders and their treatment.     

Social perspective-taking and adjustment in emotionally disturbed,learning-disabled,and normal children

Preadolescent emotionally disturbed, learning-disabled, and normal boys were compared on social perspective-taking and behavioral measures to examine possible contributions of social cognitive deficits to children's adjustment problems. Antisocial-prosocial and withdrawn-gregarious behavior dimensions were studied through subscales derived from teacher ratings. Results indicated that across all groups, high perspective-taking was associated with significantly less withdrawal than was low perspective-taking; within groups, this finding was significant only for the emotionally disturbed boys. Contrary to theoretical assumptions, antisocial behavior was not significantly related to perspective-taking across the sample. Among emotionally disturbed boys, relatively higher affective perspectivetaking was significantly correlated with higher antisocial behavior. This positive correlation for the emotionally disturbed group was significantly different from the nonsignificant negative correlation between antisocial behavior and perspective-taking among normals. Findings for learning-disabled boys were intermediate. between results for emotionally disturbed and normal boys on both perspectivetaking and behavioral measures, and the learning-disabled group generally did not differ significantly from either other group. Theoretical and clinical implications of the findings are discussed The authors acknowledge the invaluable assistance and cooperation of many teachers and principals in Jefferson County School District in Colorado, especially Ms. Norma Sobesky, coordinator of the program for Significantly Impaired Emotionally and Behaviorally Disturbed Children, and Ms. Beth Young, coordinator of the program for Perceptual and Communicative Disorders.