On the detectability of straight lines in visual noise: An extension of French’s paradigm into the millisecond domain

We report the results of a study that investigated the effects of four experimental parameters on the tachistoscopic detectability of dotted lines in a noisy background consisting of dynamic patterns of identical dots. Characteristics of the lines that were explored included dot spacing, dot numerosity, and line orientation. Dot spacing was shown to be the most powerful parameter in determining the masking effect: the closer the dots, the more easily the line was detected. Increasing the number of the dots was also effective in increasing the detectability of a line, but only up to a limit of five dots. The orientation of the line, on the other hand, did not alter its detectability. Increasing the density of the visual masking noise monotonically reduced the detectability of the line. These studies are an extension of French’s (1953, 1954) work, differing mainly in the fact that the stimulus material was presented tachistoscopically rather than in a mode that allowed prolonged (up to 5 sec) examination of the figures. Thus, they put the results in a domain in which physiological interpretations may be more critically evaluated. A comparison of the results suggests that essentially the same sorts of cognitive mechanisms are operating in the millisecond domain as in the longer exposures. This suggests that simple neurological models utilizing the concept of feature filters or detectors may be being prematurely applied to relatively complex perceptual processes.     

Triadic consistency and false heart-rate feedback

Subjects viewed slides of the Rorschach cards while listening to heart sounds that were supposedly but not actually their own. For some of the subjects the heart rate increased when they were exposed to the five achromatic cards and for some subjects the heart rate increased when they were exposed to the five chromatic cards. In addition, some subjects were told that increased heart rate was a sign of mental health (positive condition), and some that the increased heart rate was a sign of mental abnormality (negative condition) Since the heart-rate increase (behavior) and Rorschach cards associated with the increase (attitude object) are connected by a positive causal relation, triadic theory predicts that the sign of the heart-rate increase should generalize to the associated cards (i e, be positive in the positive condition and negative in the negative condition) An analysis of variance revealed such an overall significant effect Closer examination of the data, however, revealed that the triadic effects were not unambiguously occurring when the increased heart rate was associated with achromatic cards It was suggested that in this condition the unique characteristics of the cards facilitated the generation of complicating anxiety. Supportive data for this interpretation were offered     

The effects of test anxiety, sex of subject, and type of verbal reinforcement on maze performance of elementary school children

The purpose of this study was to account for children's performance in an educational setting by evaluating individual difference factors and the subjects' differential responsivities to social reinforcement The child subjects performed on Porteus mazes, which were viewed as complex, stress-inducing tasks They were differentiated in terms of sex and test anxiety levels. Each child received the same number of noncontingent reinforcements, which consisted of either verbal praise or verbal criticism or no feedback The data yielded significant triple interaction effects among anxiety, sex, and social reinforcement for the time and error scores on the mazes The data were discussed in terms of their implications for remediating performance in educational settings and their support for the theoretical conception of test anxiety as a chronic drive state The authors concluded that the extrinsic, motivating effects of verbal reinforcement can be reasonably characterized, but only if one attends to individual differences among those subjects being reinforced.     

A Bayesian prediction of four-look recognition performance from one-look data

The hypothesis that a human O’s (S’s) performance in a visual recognition task can be modelled by Bayes’ theorem was investigated. Two Ss were run for 40 experimental sessions each. Their task was to specify the direction of the gap of tachistoscopically presented Landolt rings (Cs). There were four possible gap directions, and two experimental conditions. In one condition, S responded after each stimulus presentation. In the other, a fixed-observation condition, Ss responded after four consecutive presentations of a C. Exposure durations were such that performance under both conditions was greater than chance, but less than unity. Predictions of four-look performance from one-look data were made. Overall hit rates were predicted closely. The entire pattern of each S’s four-look data was also predicted reasonably well. Further tests of the model are currently under way.     

The number of ways to label a structure

It has been observed that the number of different ways in which a graph withp points can be labelled isp! divided by the number of symmetries, and that this holds regardless of the species of structure at hand. In this note, a simple group-theoretic proof is provided.This work was supported by Grant MH 10834 from the National Institute of Mental Health.     

Toward a new conceptualization and operationalization of risk perception within the genetic counseling domain

The purpose of this paper is twofold. First, it provides an historical overview of studies of risk, risk perception, and decision making under risk within the genetic counseling domain. Second, it proposes an alternative conceptualization and operationalization for the study of risk perception. The conceptualization involves probability, adversity, incompleteness, and ambiguity. Prior studies of risk perception focus on the recurrence risk and operationalize risk perception by asking for interpretations of the magnitude of the probability of the outcome. Their focus is on the probability of a particular outcome. We formulate the problem in terms of a gamble and suggest that risk perception be operationalized in terms of the riskiness of the gamble. Our focus is on the riskiness of a decision option which entails two or more outcomes.     

CHANGING PROTECTIVE AND RISKY BEHAVIORS TO PREVENT CHILD-TO-PARENT TRANSMISSION OF CYTOMEGALOVIRUS

Child-to-parent transmission of cytomegalovirus may be reduced by increasing protective behaviors (handwashing and glove use) and decreasing risky behaviors (intimate contact between child and parent). This study showed that an educational intervention resulted in increases in reported and objective measures of protective behaviors and decreases in reported risky behaviors. Further study must determine if changes in protective and risky behavior are maintained and prevent cytomegalovirus transmission.     

The effects of hormones,Type A behavior pattern,and provocation on aggression in men

Thirty-eight male college students, classified as either Type A or Type B based on their Jenkins Activity Survey (JAS-T) scores, competed in a reaction time task that allowed them to administer shocks to an increasingly provocative fictitious opponent. Salivary testosterone and cortisol were measured both prior to and after the task. Aggression was defined as the level of shock the subject was willing to set for the opponent. The results of this study indicate that a relationship exists between endogenous testosterone levels in men and direct physical aggression. Some evidence for the moderating effects of hormones on the level of aggression expressed by Type As was observed. No direct relationship between Type A and aggression was found.