The Fraser illusion: complex figures

The cause of the Fraser illusion, which occurs when a line made up of tilted segments itself appears tilted, is examined further. In this series of experiments, we used figures that resembled the original Fraser illusion; they were more complex than those reported on in our previous paper (Stuart & Day, 1988). The figures were used to explore two theories of the Fraser illusion further: that it is the result of interactions between orientation selective units, and that it is a consequence of the local, distributed processing of orientation. The presence of background elements like those used in the original illusion led to an increase in the strength of the illusion, but the shape of these elements had no differential effect on illusion strength. There was a differential effect of the background on the assimilative and contrast illusions, owing respectively to small and large tilts of the inducing elements. The illusion was markedly reduced at small visual angles when the background was absent, but it was only slightly affected when the background was present. All these findings are difficult to explain in terms of interactions between single units, either at the same or at different scales in the image. The effects of luminance contrast and isoluminance on the illusion were not consistent with either theory, but they indicated that researchers need to consider the role of figure-ground organization in this illusion.     

Poisson signal-detection theory: Link between threshold models and the Gaussian assumption

The Gaussian model of signal detection cannot fit asymmetric data as long as the variances of the distributions are kept equal. It is therefore common practice to assume unequal variances in order to fit these data. But this assumption leads to the well-known crossover problem. The present paper provides new arguments for the abandonment of the Gaussian model with unequal variances. In its stead, this paper reevaluates multiple-parallel-threshold models. In particular, the Poisson model turns out to be very useful: it can handle data with any degree of asymmetry, giving a reasonable interpretation of the two parameters of the receiver-operating characteristic. The three-state-threshold model (Krantz, 1969) is given a new interpretation in light of the Poisson model. The slope of Poisson double-probability plots turns out to be much closer to unity than is predicted by the Gaussian approximation.     

Toward understanding sex differences in pay allocation: Agency,communion, and reward distribution behavior

This research examined the extent to which the personality characteristics of agency and communion are sex linked, and the extent to which differences in these orientations can account for sex differences in reward distribution behavior. In two studies, the agency and communion level of large samples of male and female undergraduates were assessed. As expected, males were more agentic and females were more communal. Moreover, when subjects who scored high or low on agency and high or low on communion were asked to allocate rewards between themselves and a co-worker, these personality differences were related to their allocation decisions. These results were used as the basis for discussing the role that sex-linked personality differences might play in distributive justice judgments.This article is an adaptation of a colloquium presentation at the meeting of the American Psychological Association, Los Angeles, August 1981. The research reported here was supported by NIMH grant MH29987-1, Goals, Motives, and Norms of Reward Distribution, and by NIMH Biomedical Research Support Grant from the College of Social Science, Michigan State University. The authors wish to thank Andrea Doughty for her valuable advice, and to gratefully acknowledge the help of Mark Teicher, Julie B. Klein, Sue Schnelbach, Pat Loepp, Barb Allen, Gavin Goodrich, Bob O'Hara, Kelly Bowen, Rod Hollenstein, Steve Schultz, and Mary Hurst.     

Prophylactic psychiatry

The great contributions of Gantt to the problems of prophylactic psychiatry are pointed out. The author reviews his experiences with a 30-year follow-up of a population of 1800 persons. Over the 30 years, there appeared to be a 50% increase of neuroses, which raises great problems for mental health services. The Berlevåg population was offered optimal psychiatric services. Behavior therapy of neuroses and drug treatment of depression may possibly have lowered the prevalence of mental disorders. Psychophysiologic tests were used in the project. It is hoped that such tests may be utilized for early detection and treatment of mental disorders.     

Does awareness of speech as a sequence of phones arise spontaneously?

It was found that illiterate adults could neither delete nor add a phone at the beginning of a non-word; but these tasks were rather easily performed by people with similar environment and childhood experiences, who learned to read rudimentarily as adults. Awareness of speech as a sequence of phones is thus not attained spontaneously in the course of general cognitive growth, but demands some specific training, which, for most persons, is probably provided by learning to read in the alphabetic system.     

Differential effects of person in the dog and in the human

People have marked effects on dog’s heart rate, with great individual variations for different persons. Apparently people to which the dog is attached have the greatest effect upon heart rate. Replications of the animal experiments using the psychotherapist and two other people revealed no effects upon the heart rate of a schizophrenic human. In the human the effects of people are probably best demonstrated in connection with verbal communication.     

Absence of color selectivity in the visual movement aftereffect

Lovegrove, Over, and Broerse (1972) reported that the magnitude of the movement aftereffect was reduced when the colors of the inducing and test stimuli differed, relative to when they were the same. Since this result is contrary to some earlier findings, four experiments were conducted to examine this claim. Neither the duration nor the magnitude (as measured by manual tracking) of the aftereffect generated by rotary or linear movement of contours were found to be affected by the color combinations of the inducing and stationary patterns.