Detection and discrimination of coherent motion

When viewing a pair of bars defined by the difference of spatial Gaussian functions (DOGs), human observers can discriminate accurately the relative movements of the bars, even when they differ in spatial frequency. On each trial, observers viewed two brief presentation intervals in which a pair of vertically oriented DOGs moved randomly back and forth within a restricted range. During one interval, both bars moved in the same horizontal direction and by the same magnitude (correlated movements); in the other interval, their movements were uncorrelated. When discrimination accuracy is related to the simultaneous detection of two independent movements, it was found that, if observers can detect the movements of spatially separated bars, they can tell whether their relative movements are correlated. Performance remained remarkably accurate even when the two bars differed in spatial frequency by more than two octaves or were presented separately to the two eyes. Apparently, the accurate discrimination of coherent motion involves an efficient spatial integration of optical motion information over multiple spatial locations and multiple spatial scales.     

BODY, BRAIN, AND CULTURE

Abstract. Recent work in cerebral neurology should be used to fashion a new synthesis with anthropological studies. Beginning with Paul D. Madean's model of the triune brain, we explore Ralph Wendell Burhoe's question whether creative processes result from a coadaptation, perhaps in ritual itself, of genetic and cultural information. Then we examine the division of labor between right and left cerebral hemispheres and its implications for the notions of play and "ludic recombination." Intimately related to ritual, play may function in the social construction of reality analogous to mutation and variation in organic evolution. Finally, we consider how our picture of brain functioning accords with some distinctive features of the religious systems dominant in human cultures.     

Developmental changes in predicting one's own span of short-term memory

Developmental changes in the accuracy of predicting one's own recall were studied, using preschool, third grade, and college subjects in Experiment 1 and third grade and college subjects in Experiment 2. Experiment 1 showed that prediction accuracy increased from the preschool to the college years, subjects were not influenced by a potential “expectancy” bias in the procedure, and only third grade subjects were influenced by the presence of norms about peer performance. Experiment 2 showed that third graders and college subjects lower their predictions in the face of “false” norm information, with college subjects being the only group to under predict actual recall in both experiments. Thus, although adults are significantly more accurate than elementary shool children in estimating short-term recall, their susceptibility to norm information suggests that even they have uncertainty about their exact capabilities.     

Shaping data collection congruent with experimental hypotheses

The influence of instructions and feedback from an experimenter on observational recordings of disruptive behavior was evaluated. Four subject-observers recorded four categories of disruptive behavior from videotapes of children in a classroom setting. Two sets of videotapes, labelled "baseline" and "treatment", were matched for rates of disruptive behavior in each category. The observers were told that two target behaviors were expected to decrease and the other two control behaviors were not expected to change during the treatment condition. During observational recording of treatment videotapes, the observers were given positive feedback when they reported decreases in the two target behaviors, and negative feedback when they reported either to change or increases in the two control behaviors. The target behaviors were recorded less frequently by observers, while recordings of control behaviors were unaffected during the treatment phase. These results suggest that contingent feedback to observers should be avoided as a possible source of bias in behavioral recordings.     

Effects of warm and neutral models on the attention of observational learners

The study was conducted to examine observers' attention to adults following warm and neutral interactions with them. Forty-two preschool and 36 third grade girls interacted with a pair of female models in one of three treatment conditions in which models were, respectively, warm and neutral, neutral and neutral, or warm and warm. Subiects then witnessed the models play a picture-preference game and were asked to recall the models' responses. Analyses of the children's overt attention to the models' responses revealed a greater attention to a warm model when in the presence of both a warm and neutral model and less distraction by nonsocial stimuli when at least one warm model was present. A significant positive correlation was obtained between attention to and recall of the models' responses.     

Distractibility and hypersensitivity

The present paper reports on the development of a modified problem checklist for use in normal samples of elementary school children. The two factors, Hypersensitivity and Distractibility, replicated over male and female samples. Hypersensitivity showed a significant grade effect, with a decrease between the first and second grade for both boys and girls. In contrast, boys scored higher than girls on Distractibility and there were no grade differences. Convergent validitiy data from peer judgments, in-class activity level, physical fitness measures, standardized achievement scores, and a comparison with another teacher judgment are presented. In addition, three Behavioral Problem Checklist (Quay & Peterson, 1967) dimensions, Conduct Problem, Personality Problem, and Inadequacy--Immaturity, were developed and their relationships to the independent measures, as well as to the new dimensions, are presented. The pattern of correlations of Distractibility was quite similar for boys and girls, with both being rated as Mean-Noisy by their peers. The findings for Hypersensitivity were somewhat weaker. Distractibility and Conduct Problem scores reflected a similar pattern of correlations with other variables; in a like manner, Hypersensitivity and Personality Problem scores reflected a similar pattern of correlations with other variables. Distractibility was related to an increased activity level and Hypersensitivity was related to a decreased activity level in young boys. The total number of behavior problems was related to a decrease in activity level for young girls. Older Distractible and Hypersensitive girls showed different patterns of activity level. It is proposed that problem behavior is more complex for older children and that Distractibility may be less influenced by the usual socialization process of school than is Hypersensitivity and may have some congenital antecedents.     

Behavior modification consultation in a Mexican-American school

Following consultation by two psychologists with an elementary school populated primarily by Mexican-American students, absenteeism was chosen as the first problem area to attempt to change. A between-groups experimental design was used to evaluate the effect of contigent rewards on the students' attendance. Analysis of the data showed no improvement in attendance. The results of the study were discussed in terms of (1) a more thorough behavior analysis of the absenteeism problem, (2) methodological restraints of a between-groups experimental design, (3) the need for consultants to be familiar with the community in which they work, and (4) relatedly, the success of the local school psychologist in implementing behavior modification programs.     

The psychophysical inquiry into binocular summation

Experiments that compare monocular and binocular visual performance of human psychophysical Os on a variety of visual tasks are reviewed. The review attempts to include all experiments published in English in this century, excluding work on stereopsis, rivalry, and evoked potentials. The concept of probability summation as a baseline for assessing the presence of neural summation is discussed, and the assumptions of several models for estimating probability summation are considered. Experiments are classified in terms of visual task, major categories being increment detection, flicker fusion, brightness magnitude, and contour resolution. A major conclusion is that binocular performance is superior for essentially all task categories and in most cases by a magnitude greater than that predicted by appropriate probability summation models.