Active coping with stress suppresses glucose metabolism in the rat hypothalamus

We used 18F-fluorodeoxyglucose small-animal positron-emission tomography to determine whether different styles of coping with stress are associated with different patterns of neuronal activity in the hypothalamus. Adult rats were subjected to immobilization (IMO)-stress or to a non-immobilized condition for 30 min, in random order on separate days, each of which was followed by brain-scanning. Some rats in the immobilized condition were allowed to actively cope with the stress by chewing a wooden stick during IMO, while the other immobilized rats were given nothing to chew on. Voxel-based statistical analysis of the brain imaging data shows that chewing counteracted the stress-induced increased glucose uptake in the hypothalamus to the level of the non-immobilized condition. Region-of-interest analysis of the glucose uptake values further showed that chewing significantly suppressed stress-induced increased glucose uptake in the paraventricular hypothalamic nucleus and the anterior hypothalamic area but not in the lateral hypothalamus. Together with the finding that the mean plasma corticosterone concentration at the termination of the IMO was also significantly suppressed when rats had an opportunity to chew a wooden stick, our results showed that active coping by chewing inhibited the activation of the hypothalamic-pituitary-adrenal axis to reduce the endocrine stress response.     

Perceived rationality,morality, and power of social choice as a function of interdependence structure and social value orientation

The present study examines how individuals with different social value orientations (i.e. prosocial, individualistic, and competitive) construe the rationality, morality, and power of choices in four distinct interdependence structures which systematically differ in the motives that could underlie the most prosocial or least aggressive choice: (a) altruism only, (b) altruism and cooperation, (c) altruism, cooperation, and individualism, and (d) altruism, cooperation, individualism, and competition. Results revealed that rationality ratings, and to a lesser degree morality and power ratings, increased most when the motives that could underlie a choice were part of the perceiver's social value orientation. Overall, the pattern of rationality ratings provided reasonable support for the Goal Prescribes Rationality Principle. Ratings of morality and power suggested a corresponding Goal Prescribes Morality/Power Principle (for prosocials and individualists), but revealed only mixed support for the Might Over Morality Hypothesis. Copyright © 2003 John Wiley & Sons, Ltd.     

Children’s scale errors are a natural consequence of learning to associate objects with actions: A computational model

Young children sometimes attempt an action on an object, which is inappropriate because of the object size—they make scale errors. Existing theories suggest that scale errors may result from immaturities in children's action planning system, which might be overpowered by increased complexity of object representations or developing teleofunctional bias. We used computational modelling to emulate children's learning to associate objects with actions and to select appropriate actions, given object shape and size. A computational Developmental Deep Model of Action and Naming (DDMAN) was built on the dual‐route theory of action selection, in which actions on objects are selected via a direct (nonsemantic or visual) route or an indirect (semantic) route. As in case of children, DDMAN produced scale errors: the number of errors was high at the beginning of training and decreased linearly but did not disappear completely. Inspection of emerging object–action associations revealed that these were coarsely organized by shape, hence leading DDMAN to initially select actions based on shape rather than size. With experience, DDMAN gradually learned to use size in addition to shape when selecting actions. Overall, our simulations demonstrate that children's scale errors are a natural consequence of learning to associate objects with actions.     

Decline of Hip Joint Movement Relates to Overestimation of Maximum Forward Reach in Elderly Persons

The authors aimed to characterize age-related changes in the performance of maximum reach and identify kinematic parameters that explain the age-related discrepancy between perceived and actual maximum reach distance. Maximum reach was evaluated in 22 younger women (21.3 years old) and 20 older women (81.2 years old). Both the perceived and actual maximum forward reach and forward excursion of the center of pressure was shorter in older women. Older women also overestimated their maximum reach distance to a greater extent. Decline of movement at the hip joint specifically correlated with both the maximum distance and the overestimation. Based on these results, decline of hip control may be a primary factor for the age-related retardation of perceived and actual maximum reach.     

An integration of color and motion information in visual scene analyses

To analyze complex scenes efficiently, the human visual system performs perceptual groupings based on various features (e.g., color and motion) of the visual elements in a scene. Although previous studies demonstrated that such groupings can be based on a single feature (e.g., either color or motion information), here we show that the visual system also performs scene analyses based on a combination of two features. We presented subjects with a mixture of red and green dots moving in various directions. Although the pairings between color and motion information were variable across the dots (e.g., one red dot moved upward while another moved rightward), subjects' perceptions of the color-motion pairings were significantly biased when the randomly paired dots were flanked by additional dots with consistent color-motion pairings. These results indicate that the visual system resolves local ambiguities in color-motion pairings using unambiguous pairings in surrounds, demonstrating a new type of scene analysis based on the combination of two featural cues.     

Role of biological-motion information in recognition of facial expressions by young children

Data on the development of the perception of facial biological motion during preschool years are disproportionately scarce. We investigated the ability of preschoolers to recognise happy, angry, and surprised expressions, and eye-closing facial movements on the basis of facial biological motion. Children aged 4 years (n = 18) and 5-6 years (n = 19), and adults (n = 17) participated in a matching task, in which they were required to match the point-light displays of facial expressions to prototypic schematic images of facial expressions and facial movement. The results revealed that the ability to recognise facial expressions from biological motion emerges as early as the age of 4 years. This ability was evident for happy expressions at the age of 4 years; 5-6-year-olds reliably recognised surprised as well as happy expressions. The theoretical significances of these findings are discussed.     

Eliminating national stereotypes: Direct versus indirect disconfirmation of beliefs in covariation

Two modes of disconfirmation of national stereotypes were compared. It was hypo-thesized that stereotypes should be revised either by stereotype-inconsistent cases from the primary target (i.e., direct disconfirmation) or by instances which belong to an alternative target but possess features stereotypic of the primary target (indirect disconfirmation). It was further predicted that politically liberal individuals would show greater change in their national stereotypes than conservatives. Two experiments were conducted in which the salience of directly and indirectly disconfirming information regarding different nations was manipulated. The results indicated that indirect disconfirmation generally had as much impact as direct disconfirmation, but that the effects were particularly visible among liberal participants. Conservatives tended to respond in a reactive manner which preserved or exaggerated their original views. A new theoretical framework for the study of stereotype change and implications for its application were discussed.     

Knowing minds: Culture and perceptions of mental state access

How does culture influence the ways in which individuals reflect upon their knowledge of others’ mental states? We addressed this question in a two‐study cross‐cultural investigation examining perceptions of mental state access in the United States and Japan. Study 1 (n = 100) revealed that American participants reported greater mental state access than did Japanese participants. Study 2 (n = 146) showed that both Americans and Japanese perceived greater access to the mental states of a close friend relative to a casual friend and that the observed cultural differences in perceived mental state access to a close friend’s mental states were mediated by how much access was considered appropriate. Overall, the results indicate that culturally variable norms specifying appropriate levels of mental state access play an important role in how individuals estimate their knowledge of other people’s minds in close relationships.