Cortical dynamics of visual motion perception: short-range and long-range apparent motion.

This article describes further evidence for a new neural network theory of biological motion perception. The theory clarifies why parallel streams V1----V2, V1----MT, and V1----V2----MT exist for static form and motion form processing among the areas V1, V2, and MT of visual cortex. The theory suggests that the static form system (Static BCS) generates emergent boundary segmentations whose outputs are insensitive to direction-of-contrast and to direction-of-motion, whereas the motion form system (Motion BCS) generates emergent boundary segmentations whose outputs are insensitive to direction-of-contrast but sensitive to direction-of-motion. The theory is used to explain classical and recent data about short-range and long-range apparent motion percepts that have not yet been explained by alternative models. These data include beta motion, split motion, gamma motion and reverse-contrast gamma motion, delta motion, and visual inertia. Also included are the transition from group motion to element motion in response to a Ternus display as the interstimulus interval (ISI) decreases; group motion in response to a reverse-contrast Ternus display even at short ISIs; speed-up of motion velocity as interflash distance increases or flash duration decreases; dependence of the transition from element motion to group motion on stimulus duration and size, various classical dependencies between flash duration, spatial separation, ISI, and motion threshold known as Korte's laws; dependence of motion strength on stimulus orientation and spatial frequency; short-range and long-range form-color interactions; and binocular interactions of flashes to different eyes.     

ALCOVE: an exemplar-based connectionist model of category learning.

ALCOVE (attention learning covering map) is a connectionist model of category learning that incorporates an exemplar-based representation (Medin & Schaffer, 1978; Nosofsky, 1986) with error-driven learning (Gluck & Bower, 1988; Rumelhart, Hinton, & Williams, 1986). Alcove selectively attends to relevant stimulus dimensions, is sensitive to correlated dimensions, can account for a form of base-rate neglect, does not suffer catastrophic forgetting, and can exhibit 3-stage (U-shaped) learning of high-frequency exceptions to rules, whereas such effects are not easily accounted for by models using other combinations of representation and learning method.     

Disorder as harmful dysfunction: a conceptual critique of DSM-III-R's definition of mental disorder.

The Diagnostic and Statistical Manual of Mental Disorders (3rd ed., rev.; DSM-III-R) operationally defines disorder essentially as "statistically unexpectable distress or disability." This definition is an attempt to operationalize 2 basic principles: that a disorder is harmful and that a disorder is a dysfunction (i.e., an inability of some internal mechanism to perform its natural function). However, the definition fails to capture the idea of "dysfunction" and so fails to validly distinguish disorders from nondisorders, leading to invalidities in many of DSM-III-R's specific diagnostic criteria. These problems with validity are traced to DSM-III-R's strategies for increasing reliability.     

The Effects of Decision Outcome Dispersion Upon Organizational Decision Making

The effects of varying decision outcome dispersion on organizational decision making were investigated under individual and group decision making conditions. Thirty-six female and pg]36 male subjects made decisions for organizational decision scenarios in which outcomes affected primarily the decision maker, people other than the decision maker, or a group of which the decision maker was a member. Subjects rated their levels of perceived risk and confidence in their decisions and made decisions within a simulated context of either a small or a large organization. Results indicated that subjects perceived significantly less risk and more confidence in their decisions when outcomes affected primarily themselves rather than others regardless of whether the decisions were made individually or by a group. Males perceived their decisions as significantly more risky than females. Induced organizational size did not significantly influence decision making.

     

Black South Africans and Canadians on neuroticism as a dimension of personality.

This study was done to assess gender and cultural differences on neuroticism as a dimension of personality among both Canadians and Black South Africans. No statistically significant cross-cultural differences were observed. However, statistically significant gender differences emerged among both Canadian and African men and women, with the latter scoring higher on neuroticism than the former.     

Premenstrual symptoms: the role of irrational thinking.

104 women, between the ages of 18 and 45 years, were surveyed to investigate the relationship between premenstrual symptomatology, as measured by the Modified Menstrual Distress Questionnaire, and irrational thinking, as measured by the General Attitude and Belief Scale. The women who reported greater premenstrual symptomatology also reported significantly higher scores in the "need for comfort" irrationality subscale. This indicated that these women had particular difficulty dealing with hassles and the resulting feelings of tension and irritability in the premenstruum. It was suggested that the absence of significant effects for other rationality-irrationality subscales could be associated with testing at different times during the menstrual cycle. Irrationality, like other conditions (such as anxiety and depression) prevalent in the premenstruum, could change in intensity across phases of the menstrual cycle.     

Interpretation style and reactance in counselor's social influence.

This study compared two different interpretation styles (tentative and absolute), two levels of subjects' reactance (high and low), and gender on the counselor's social influence, willingness to see the counselor, willingness to help, ability to help, and subjects' anger. No significant main effects or interaction were found for the counselor's social influence, but men in contrast to women perceived the counselor as more willing to help and indicated that they were more willing to see the portrayed counselor. Highly reactant subjects were more willing to see the counselor when absolute interpretations were used; they also thought the counselor was more willing to help when absolute interpretations were used, whereas low reactant subjects thought the counselor was more willing to help when tentative interpretations were used. Mixed results were found for subjects' anger.     

Depression, suicide ideation, and aggression among high school students whose parents are divorced and use alcohol at home.

106 high school students from a small rural high school completed the Children of Alcoholics Scale, Zaks and Walters' Aggression Scale, Beck Depression Scale, and a modified version of the Beck Scale of Suicide Ideation. Analyses of variance showed boys were not experiencing suicide ideation any more than girls; suicide ideation was similar across the four grades, but on aggression alcohol-dependent boys scored significantly higher than girls, and in Grade 9 boys' scores were significantly higher than those in Grade 10. The sophomores' scores on alcohol dependency were significantly lower than the freshmen's scores. Boys and children from divorced homes had higher scores on aggression than girls and children from nondivorced homes. Children from homes in which alcohol was used had higher depression scores than children from nonalcoholic homes. Freshman girls and sophomore boys had higher depression scores than senior boys and girls. A Pearson r of 0.28 between scores on alcohol dependency and suicide ideation was significant, but research is needed to understand better the associations of thoughts of suicide and drug-alcohol dependency among these high school students so strategies for prevention and intervention can be focused.     

Correlations of Beck Depression Inventory and Reynolds Adolescent Depression Scale.

The scores of 15 adolescents who had a primary diagnosis of Posttraumatic Stress Disorder, 21 of Conduct Disorder, and 23 control subjects on the Beck and Reynolds depression scales were correlated .58 over-all, .73 for the Posttraumatic group, .48 for the Conduct Disordered group, but .37 for controls. The Reynolds scale did not identify depression in these adolescents as effectively as did the Beck scale.