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.     

Semantic congruity effects in perceptual comparisons

Semantic congruity effects occur when, as in Experiment 1, for example, the time to select the shorter of two relatively short lines is faster than the time to select the longer; conversely, selection of the longer of two relatively long lines is faster than selection of the shorter. Semantic congruity effects are also demonstrated in experiments requiring comparisons of the heaviness of weights (Experiment 2) and horizontal extent (Experiment 3). In Experiment 1, the magnitude of the semantic congruity effect was larger under conditions emphasizing accuracy rather than speed and when the comparison was difficult. In fact, when comparisons were errorless, the effect was minimal (20 msec), thereby replicating previous failures to obtain the effect with supraliminal perceptual comparisons (Banks, Mermelstein, & Yu, 1982; Marschark & Paivio, 1981; Petrusic & Baranski, 1988a). In confirmation of Henmon's (1911) introspective analyses of psychophysical comparisons, Experiments 2 and 3 extend the range of the semantic congruity effect to include judgments of confidence. However, in each of the three experiments, semantic congruity effects were not evident with the response-accuracy measure. Finally, using highly confusable stimuli, in Experiment 3 the magnitude of the semantic congruity effect was shown to be larger for error than for correct response times. The implications of these findings for a decisional locus of the effect and for the semantic coding theory are discussed.     

Normal cerebrospinal fluid findings in spinal tumors--an analysis of 503 cases

Till now almost nothing has been published about normal liquor findings in spinal cord tumours. Out of 503 cases there were normal findings of total proteins and cells in 30 cases (6 per cent). A connection with the severity of the compression-syndrome was not evident. Nevertheless liquor examinations are important in diseases of the medulla spinalis. This is especially useful in the differential diagnostical demarcation of inflammable spinal cord diseases, accompanying reactions or bleedings into the spinal channel.     

Sacred marriage in the study of religion: A perspective from India on a concept that grew out of the ancient near east

Current scholarly understandings of ‘sacred marriage’ are seriously impaired by work that focuses on ancient cultures, primarily in the Near East, but also in Greece. Even when ‘diffusionism’, ‘patternism’, and an apparent preoccupation with rituals presumed sexual are all factored out, modern scholars offer little new because they appeal to rituals never witnessed and to fragmentary texts which we can only hope had some connection to ritual. Focusing on an extant ritual tradition in India with a 200-year-old festival and an explicitly associated text from the 13th century , Harman suggests that here, at least, sacred marriage is an elaborate, ritual statement of kinship responsibilities and obligations reestablished each year among deities and between deities and selected human beings.     

Objective and simulated stimulation: an empirical study of the effect of indirect suggestion on motor behavior

In an experimental investigation it is demonstrated that motor behavior-in contrast to the opinion forwarded in the literature-is not only elicitable by means of direct persuasion, but also to a great extend by mere indirect suggestion, (feigning of stimuli). A differential investigation of these effects provided evidence that reactions to feigned stimuli are highly person specific and relatively homogenous concerning the respective instruments whereas objective stimuli lead to reactions relatively specific for the respective instrument applied. The findings are interpreted as an analog on to placebo-effects in the area of motor behavior. Their extend may be seen as an argument for a stronger concern with subjective reaction tendencies in this field.     

Insight without awareness: On the interaction of verbalization, instruction and practice in a simulated process control task

Four experiments in which subjects learned to control two versions of a complex simulated process control task show that verbalizable knowledge of procedures used to perform these tasks is very limited and is acquired late in learning. Individual learning curves associated with these tasks showed sudden improvements in performance, which were not accompanied by a similar increase in verbalizable knowledge. It was also found that verbal instructions consisting of exemplar memorization, strategies for rule induction, simple heuristics, and experts' instructions were all effective in enhancing novice subjects' performance. A theoretical framework is proposed in which subjects draw on two separate but interacting knowledge structures to perform these tasks. One knowledge structure is based on memory for past experiences (close analogies), and the other is based on one's current mental model of the task. Implicit sets of competing rules that control response selection are derived from both sources of knowledge. It is suggested that dissociations between task performance and verbalizing occur because memory-based processing tends to have more control over response selection because of its greater specificity, whereas a mental model tends to be the preferred mode for verbal reporting because of its greater accessibility.     

Feelings of attachment to siblings and well-being in later life

On the basis of an adult model of sibling attachment, I hypothesized that the well-being of older persons depends on their perception of the closeness of the sibling bond, on their perception of any disruption of that bond, and on the sex combination of the siblings being considered. In all, 83 persons, aged 61 to 91 years, were interviewed about their relationships with each of their living siblings. They rated their feelings of closeness, conflict or rivalry, and indifference to the sibling. A measure of depression was used as the indicator of well-being. Separate correlational analyses were carried out for the four sex combinations of siblings. Closeness of the bond to a sister (by both men and women) was related to less depression. Also, women's perceptions of conflict and indifference in their relationships with sisters were related to increased depression. Findings are interpreted in terms of attachment theory and sex role expectations.     

Forecasting the impact of the federal sentencing guidelines

The Sentencing Reform Act of 1984, which created the U.S. Sentencing Commission, required that the commisson consider prison capacity in drafting sentencing guidelines. As part of the commission's efforts to meet this requirement, we developed a computer simulation capable of projecting the impact of the commission's guidelines on future sentences and prison populations. According to our projections, “straight” probation sentences will be reduced significantly under the guidelines. However, reducing the use of probation will generate only modest demands on the prisons, and then mostly for community corrections phased in over the course of 5 years. We also project that, while average time served for violent offenses will increase substantially, average time served for most property crimes will remain largely the same. Finally, while we forecast that federal prison populations will grow markedly by the end of this century, this is more a result of the Anti-Drug Abuse Act of 1986 and the career offender provision of the Comprehensive Crime Control Act of 1984 than a result of the guidelines.     

Setting and response generalization in rational-emotive therapy: A case study

A single case study (n=1) conducted during therapy investigated the relationship between disputing irrational beliefs in vivo and setting and response generalization. Irrational beliefs associated with the subject's anger and depression were disputed at different intervals over a ten week period utilizing a multiple baseline design across four classes in a school setting (setting 1). Depression and anger were rated several times each week. The subject's level of anxiety was also rated in setting 1 but the irrational beliefs associated with it were not disputed. Anger, depression, and anxiety were rated without disputation in a separate work setting (setting 2). Affect ratings significantly decreased across both settings throughout the ten week period. Results indicated that 1) disputing irrational beliefs associated with anger and depression in setting 1 led to reductions in anxiety in this setting (response generalization), 2) anger and depression reductions in setting 2 paralleled setting 1 reductions (setting generalization), and 3) anxiety reductionsWilliam J. Ruth, PhD, Staff Psychologist and practicum supervisor, Institute for Rational-Emotive Therapy, NY City; School Psychologist, Board of Cooperative Educational Services, Southern Westchester.Raymond DiGiuseppe, PhD, ABPP, Director of Training and Research, Institute for Rational-Emotive Therapy, NY City; Graduate Professor, St. John's University, NY City; co-author,Practitioner's Guide to Rational-Emotive Therapy and RET with Alcoholics and Substance Abusers.