Visual perception of surface curvature: psychophysics of curvature detection induced by motion parallax

The continuous approach to optic-flow processing shows that the curvature of a moving surface is related to a second spatial derivative of the velocity field, the spin variation (Droulez & Cornilleau-Pérès, 1989). With this approach as a theoretical framework, visual sensitivity to the curvature of a cylinder in motion was measured using a task of discrimination between cylindrical and planar patches. The results confirm the predictions suggested by the theory: (1) Sensitivity to curvature was always greater when the cylinder axis and the frontal translation were parallel than when they were orthogonal. The ratio of curvature detection thresholds in the two cases was between 1.3 and 2.5; the value predicted from the spin variation theory is about 2. (2) Sensitivity to curvature increased strongly with the velocity of the motion but was only weakly affected by its amplitude and the duration of viewing for the range of values used in our experiments.     

TREATING WOMEN AS SEX-OBJECTS

In this paper we have two related aims. First, we aim to present an account of what it is to treat women as sex-objects.¹ Like other philosophical writers in the field, we hold that the central idea in an account of such treatment is the failure to treat women with proper respect in sexual behavior. This idea has been cashed out in terms of using,² and in terms of dehumanization or failure to accord equal rights to freedom and welfare.³ However, we believe that there is a central deficiency in most such philosophical accounts of treating women as sex-objects, namely, a failure to outline in any detail a theory of interpersonal norms so that one can grasp in more concrete terms what it is to avoid treating a woman as a sex-object. We aim to rectify this deficiency by presenting a model of interpersonal norms based on the work of the social psychologist Chris Argyris.⁴     

Using item-specific instructional information in achievement modeling

The problem of detecting instructional sensitivity (item basis) in test items is considered. An illustration is given which shows that for tests with many biased items, traditional item bias detection schemes give a very poor assessment of bias. A new method is proposed instead. This method extends item response theory (IRT) by including item-specific auxiliary measurement information related to opportunity-to-learn. Item-specific variation in measurement relations across students with varying opportunity-to-learn is allowed for.This paper was presented at the 1987 AERA meeting in Washington, DC. This research was supported by grant OERI-G-86-003 from the Office of Educational Research and Improvement, Department of Education. The author thanks Michael Hollis and Chih-fen Kao for valuable research assistance, and appreciates valuable comments made by an anonymous reviewer.     

Attributions of responsibility for date and stranger rape

This study examined the effects of the victim-perpetrator relationship on college students' attributions of responsibility for rape. In addition, the rape specificity of these attributions was investigated. College females and males read one of six scenarios that depicted a rape or a proposition, and that varied according to the victim-perpetrator relationship (steady dating partners/acquaintances on a first date/strangers). Then they rated seven responsibility attributions for the rape or proposition. Results indicated that most forms of victim responsibility were stronger for the rape and proposition on a date than for the incidents between strangers, and the findings concerning the perpetrator's responsibility were mixed. The pattern of both victim- and perpetrator-responsibility attributions suggests that both a rape and proposition on a date, compared to incidents between strangers, elicit stronger sex role and sexual attributions. Moreover, male subjects, in comparison to female subjects, gave higher ratings to several responsibility attributions, and these, also, are linked to sex role and sexual considerations. Further, the data revealed that only the perpetrator-responsibility attributions were stronger for the rape than the proposition.This research was supported by the University of Connecticut Research Foundation Grant No. 1171-000-22-00215-35-760. The authors thank Laurin Hafner for his help with the data analysis.     

Factor structure in groups selected on observed scores

A new method is proposed for estimating factor means and factor covariances in a group of individuals selected on their observed scores. The selection variable is, for example, the total score on an admissions test. Given a factor model for the test items based on the group of test takers, we may be interested in the factor structure for those in the top quartile. The differences in factor means and covariances between this selected group and the full group gives useful information both on successful test performance and on test validity. The new method draws on the classic Pearson-Lawley selection formulas. It avoids the fallacy of factor analysis on the selected group, which would lead to incorrect estimates. The new method is applied to a simple factor structure model for the GMAT test. Although the majority of the GMAT items test verbal skills, it is found that a quantitative factor shows the greatest change in moving from average to top quartile test takers.     

Choice,Control, and Adaptation Among Elderly Residents of Sheltered Care Settings1

This study examined how elderly residents' adaptation is affected by naturally occurring levels of choice and control in sheltered care facilities. A representative sample of 244 residential care facilities was assessed with the Multiphasic Environmental Assessment Procedure, which measures the quality of residential settings for older people. Overall, facility policies allowing more choice and control were associated with better rated resident well-being, less use of health, daily living assistance, and social-recreational services, and more integration in the community. Policy clarity and the facility social climate factors of independence, influence, and organization mediated the relationship between choice and control and adaptation, and also independently affected residents' adaptation. In addition, in facilities with functionally able residents, more choice and independence were associated with less use of services; in facilities with residents of poor functional ability, choice and independence were unrelated to use of services. Thus, policies that promote more choice and independence may improve adaptation among functionally able residents of sheltered care facilities, without having a detrimental influence on poorly functioning residents.     

Reading with partial phonology: Developmental phonological dyslexia

Recent psycholinguistic investigations have advanced our understanding of the acquired dyslexias. Developmental analogues have been described to some of these disorders. A new case of developmental phonological dyslexia is described here. A.H. is an intelligent 10-year-old boy with no neurological abnormality. Reading and spelling are below age level. A.H. is poorer at reading words than nonwords. The majority of his errors are paralexias: visual, derivations, or visuosemantic. Spelling-to-sound regularity does not affect the ability to read aloud. A.H.'s reading performance is significantly impaired when words are presented typed in reverse order, thereby prohibiting global strategies. Spelling of nonwords is no better than reading of nonwords. Only one-fifth of spelling errors are phonologically valid. A.H. has imperfect development of both the phonological route to reading and the phonological route to spelling.A shortened version of this paper was presented at the European meeting of the International Neuropsychological Society, Lisbon, Portugal, June 1983.     

On structural equation modeling with data that are not missing completely at random

A general latent variable model is given which includes the specification of a missing data mechanism. This framework allows for an elucidating discussion of existing general multivariate theory bearing on maximum likelihood estimation with missing data. Here, missing completely at random is not a prerequisite for unbiased estimation in large samples, as when using the traditional listwise or pairwise present data approaches. The theory is connected with old and new results in the area of selection and factorial invariance. It is pointed out that in many applications, maximum likelihood estimation with missing data may be carried out by existing structural equation modeling software, such as LISREL and LISCOMP. Several sets of artifical data are generated within the general model framework. The proposed estimator is compared to the two traditional ones and found superior.The research of the first author was supported by grant No. SES-8312583 from the National Science Foundation and by a Spencer Foundation grant. We wish to thank Chuen-Rong Chan for drawing the path diagram.     

Three-dimensional perspective drawing of two-dimensional functions with microcomputers

In this paper, we present a BASIC program for Apple II series computers that allows the user to obtain perspective drawings of two-dimensional functions of known analytical expression. Also, we outline a procedure for obtaining perspective representations of two-dimensional arrays of data using the same program. The program should run on any computer with graphics mode with only slight modifications in the graphics commands.