The perception of continuous curves in dot stimuli

Two categorisation experiments are reported in which the perceptual phenomenon that some simple arrays of discrete dots appear as a continuous curve whereas others are perceived as an angular contour or as consisting of separate groups of dots was investigated. Triplets of dots were presented in the first experiment, and complete or incomplete regular dot polygons (ie dots positioned on the vertices of imaginary regular polygons) in the second. In both experiments the perception of a curve versus an angle was determined mainly by the relative orientations of the dots, ie by the angles between successive virtual lines, whereas the lengths of the virtual lines had relatively little influence. In experiment 2 the number of displayed dots was shown to be a second independent factor for perceiving continuity. These results are in agreement with results from experiments on dipole textures discrimination, and suggest the psychological existence and importance of virtual lines in the visual processing of dot stimuli.     

Stereokinesis with moving visual phantoms

When a flat pattern composed of a solid ellipse with two symmetrical semirings (corresponding to the visible parts of a contour ellipse whose major axis is perpendicular to that of the solid ellipse) is slowly rotated in the frontoparallel plane, a compelling three-dimensional impression occurs. Subjects report seeing an egg-shaped object that is inserted into a circular ring: the two objects move solidly into three-dimensional space and a moving visual phantom is generated so that the ring appears completed by an illusory curved bar in the region closest to the observer during rotation. A number of variations of this illusion are presented. It is shown that stereokinetic phantoms (i) maintain the shape of the inducing elements; (ii) appear only after the stereokinetic transformation has taken place; and (iii) depend on the organization of the three-dimensional percept as a whole. Relations between stereokinetic phantoms and other completion phenomena are presented and discussed.     

Relative effectiveness of three stimulus variables for locating a moving sound source

A study is reported in which it is shown that observers can use at least three types of acoustic variables that indicate reliably when a moving sound source is passing: interaural temporal differences, the Doppler effect, and amplitude change. Each of these variables was presented in isolation and each was successful in indicating when a (stimulated) moving sound source passed an observer. These three variables were put into competition (with each indicating that closest passage occurred at a different time) in an effort to determine their relative importance. It was found that amplitude change dominated interaural temporal differences which, in turn, dominated the Doppler effect stimulus variable. The results are discussed in terms of two interpretations. First, it is possible that subjects based their judgements on the potential discriminability of each stimulus variable. However, because the stimuli used involved easily discriminable changes, subjects may instead have based their judgements on the independence of a stimulus variable from different environmental situation conditions. The dominance ordering obtained supports the second interpretation.     

Individual differences and measures of aggression in laboratory studies

After inducing hostility toward a confederate by threatening subjects' self-esteem, subjects were then given the opportunity either to deliver shocks (Experiment 1) or to withhold rewards (Experiment 2) from their confederate. Physiological measures were taken prior to the hostility induction, shortly after the induction and, finally, after the opportunity to aggress. Measures of individual differences relating to aggressive behavior were also considered. While the experimental manipulation was the best predictor in the ‘withholding rewards’ condition, measures of dissipation-rumination tendencies and emotional vulnerability were the best predictors in the ‘shock administration’ condition. In both conditions, systolic blood pressure seemed to reflect differences in arousal as a function of the hostility induction procedure, while subjects in the withhold rewards procedure also showed a decrease in systolic pressure after having an opportunity to aggress toward the confederate. It was concluded that not only is the withholding of rewards a more ethically acceptable procedure than shock administration, but it is also more likely to reflect experimental rather than individual difference affects.     

Investigation of a social-interactional model of depression with mildly depressed males and females

Recent research has explored social-interactional factors in the etiology and maintenance of depression. The current investigation further explored the social-interactional model using face-to-face interactions between depressed and nondepressed individuals, as well as the applicability of this model to observed differences in male and female depression. Forty depressed and 40 nondepressed subjects interacted with same or opposite-sex partners. The 20-minute interactions were videotaped and scored with a behavioral coding system. Subjects completed questionnaires concerning perceptions of their partners and the interaction. Results indicated that depressed and non-depressed subjects behaved similarly during the interactions. However, depression was associated with a number of socially unskilled behaviors. Depression in males was related to additional skills deficits not observed for females. While male and female self-report of depression did not differ, males consistently reported greater negative affect. Partner impressions differed based upon sex of partner, and not his or her level of depression. The robustness of the social-interactional model and methodological considerations for future research with this model are discussed.This article is based on the first author's master's thesis conducted under the supervision of the second author who is now at Catholic University. Portions of this research were presented at the 32nd annual meeting of the Southeastern Psychological Association.The authors wish to thank George A. Clum and Thomas H. Ollendick for serving as committee members; Teresa K. Meade for her invaluable help in data collection; and Katie Bechtel, Ruth Townsley, and Mike Cobler for their assistance in scoring and coding data. Thanks also to an anonymous reviewer for helpful comments on an earlier draft of this paper.     

The influence of individual and family characteristics upon career aspirations of girls during childhood and adolescence

The term pioneer is used for girls aspiring to male-dominated careers. This longitudinal study assesses the career choices of 68 middle-class girls during childhood (8–13 years, Phase I) and again during adolescence (13–18 years, Phase II), and investigates the relation between pioneering career choice and personal and family characteristics. Subjects were originally selected for exposure vs nonexposure to exogenous hormones during pregnancy. In childhood, pioneers were somewhat older, were more often persistent tomboys, had higher IQs, and had parents with higher educational attainment. In adolescence, paternal education was the only variable that showed the same relation to career choice. Adolescent girls who had wanted to get married at the time of the childhood assessment were now less likely to choose pioneering careers. Adolescent pioneers also had higher educational aspirations than nonpioneers and less likely anticipated being married within ten years than nonpioneers. A number of statistically borderline relationships were also observed: pioneers had somewhat fewer older brothers than nonpioneers, less often came from homes in which traditional femininity was stressed, and more frequently had mothers who had worked outside the home throughout their daughters' school years than mothers of nonpioneers. Prenatal exposure to exogenous sex hormones was not related to career choice during either childhood or adolescence.     

3-6岁幼儿在分类实验中概括能力的发展

本研究通过设计不同性质的分类实验,探讨3-6岁幼儿抽象概括能力的发展。我们根据年龄将幼儿分为四个组,每组80人,共320人。通过实验获得以下几点。①幼儿在各种不同性质的分类实验中可表现为四级不同的水平,如从根据表面的个别特征进行分类发展到根据内部的本质特征进行分类,从一维角度的分类发展到从两维角度来分类等。⑦达到各个水平的年龄不是截然划分的,而是互相交织的,随着年龄的增加,低级水平的人数不断减少,高级水平的人数不断增加。所以年龄阶段之间既有质的变化,又有量的变化。③对于不同性质的分类材料,各年龄所达到的概括水平也不同,分类材料的难度越大,概括水平越低。④儿童概括水平的高低受教育条件的影响。