Effect of ethnic group membership on ethnic identity,race-related stress,and quality of life

This study examined the effect of ethnic group membership on ethnic identity, race-related stress, and quality of life (QOL). The Multigroup Ethnic Identity Measure, the Index of Race Related Stress--Brief Version, and the World Health Organization Quality of Life--Brief Version were administered to 160 male and female participants from 3 ethnic groups (African American, Asian American, and Latino American). Results indicated that African American participants had significantly higher race-related stress, ethnic identity, and psychological QOL scores than did Asian and Latino American participants. A stepwise multiple regression analysis revealed that ethnic identity and cultural racism were significant predictors of QOL and accounted for 16% of the total variance for the entire sample.     

Risk perception and behavior: Pessimism,realism, and optimism about aids-related health behavior

Abstract

This study investigates the perceived risk of becoming infected with HIV for heterosexuals with multiple sexual partners, examines cognitive and motivational antecedents of biases in risk perception, and relates these biases to behavior. We obtained a moderate degree of optimism in a longitudinal study based on a sample of 535 visitors of a STD clinic. Further analyses—after classifying subjects as “pessimists”, “realists”, or “optimists”—revealed that pessimists were extremely pessimistic and optimists remarkably optimistic. Optimism increased with perceived control and decreased with prior experience, supporting a cognitive explanation of optimism. The data also provided some support for a motivational explanation: optimists who scored higher on a defensive coping style were more optimistic about their risks. Contrary to other findings, we found a positive relation between optimism and intentions to reduce risks. Furthermore, results revealed that optimists showed lower levels of subsequent behavioral risk. It was concluded that optimists were not unrealistically optimistic about their personal vulnerability. but rather that pessimists were unrealistically pessimistic. Previous behavior was found to be the best predictor of subsequent behavior. Although measures of perceived risk were also related to subsequent behavior, their predictive power was rather modest.     

Patterns of brain acetylcholine release predict individual differences in preferred learning strategies in rats

Acetylcholine release was measured simultaneously in the hippocampus and dorsal striatum of rats before and during training on a maze that could be learned using either a hippocampus-dependent spatial strategy or a dorsal striatum-dependent turning strategy. A probe trial administered after rats reached a criterion of 9/10 correct responses revealed that about half of the rats used a spatial strategy and half a turning strategy to solve the task. Acetylcholine release in the hippocampus, as well as the ratio of acetylcholine release in the hippocampus vs. the dorsal striatum, measured either before or during training, predicted these individual differences in strategy selection during learning. These findings suggest that differences in release of acetylcholine across brain areas may provide a neurobiological marker of individual differences in selection of the strategies rats use to solve a learning task.     

Colour constancy in goldfish and man: influence of surround size and lightness

Colour constancy was investigated by using a series of 10 simultaneously presented surface colours ranging in small steps from green through gray to red-purple. Goldfish were trained to select one medium test field when the entire setup was illuminated with white light. In the tests, either red or green illumination was used. Colour constancy, as inferred from the choice behaviour, was perfect under green illumination when the test fields were presented on a gray or a white background, but imperfect on a black background. Under red illumination and a white background, however, colour constancy was overcompensated. Here, a colour contrast effect was observed. The influence of background lightness was also found when the surround was restricted to a narrow annulus of 4-11 mm width (test field diameter: 14 mm). By applying colour metrics it could be shown that the von Kries coefficient law can describe the overall effect of colour constancy. For an explanation of the effect of surround size and lightness, lateral inhibitory interactions have to be assumed in addition, which are also responsible for simultaneous colour contrast. Very similar results were obtained in experiments with the same colours in human subjects. They had to name the test field appearing 'neutral' under the different illumination and surround conditions, as tested in the goldfish experiment.     

Prechtl's assessment of general movements: a diagnostic tool for the functional assessment of the young nervous system

General movements (GMs) are part of the spontaneous movement repertoire and are present from early fetal life onwards until the end of the first half a year of life. GMs are complex, occur frequently, and last long enough to be observed properly. They involve the whole body in a variable sequence of arm, leg, neck, and trunk movements. They wax and wane in intensity, force and speed, and they have a gradual beginning and end. Rotations along the axis of the limbs and slight changes in the direction of movements make them fluent and elegant and create the impression of complexity and variability. If the nervous system is impaired, GMs loose their complex and variable character and become monotonous and poor. Two specific abnormal GM patterns reliably predict later cerebral palsy: 1) a persistent pattern of cramped-synchronized GMs. The movements appear rigid and lack the normal smooth and fluent character. Limb and trunk muscles contract and relax almost simultaneously. 2) The absence of GMs of fidgety character. So-called fidgety movements are small movements of moderate speed with variable acceleration of neck, trunk, and limbs in all directions. Normally, they are the predominant movement pattern in an awake infant at 3 to 5 months. Beside a sensitivity and specificity of 95% each, the assessment of GMs is quick, noninvasive, even nonintrusive, and cost-effective compared with other techniques, e.g., magnetic resonance imaging, brain ultrasound, and traditional neurological examination.