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.     

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.     

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.     

Shrinkage in the perceived duration of speech and tone by acoustic replacement1

Abstract: To investigate mechanisms for perceiving the duration of an auditory event, an effect of perceptual grouping upon perceived duration was studied psychophysically. In the first experiment, the perceived duration of a spoken word was measured under three conditions of acoustic continuity (i.e., (a) intact, (b) noise‐replaced, and (c) gap‐replaced) as a function of the duration of the target stimulus. Under the noise‐replaced condition, a portion of the target stimulus was physically replaced with a noise burst. Under the gap‐replaced condition, the replacement was made with a gap. The gap‐replacement resulted in a prominent shrinkage of the perceived duration. In the case of noise‐replacement, the amount of shrinkage was moderate but highly significant, although the word employed was perceived to be phonetically intact. Independent of this effect of replacement, the amount of shrinkage was also affected by the physical duration of the target stimulus. The second experiment tested an effect of noise replacement on the perceived duration of a tone burst. In this case, the noise replacement also shrunk the perceived duration of the non‐speech stimulus. This noise‐induced shrinkage could be regarded as being general for the auditory duration. The phenomenon is discussed in relation to a revised model for perceived duration.     

Homogeneity perception as a reaction to identity threat: effects of status difference in a simulated society game

The present study examined how members of low status groups would react to a threat to their social identity. Undergraduates participated in a ‘simulated society game,’ and were divided into four groups, each of which was assigned either a high or low status. During a series of game sessions with intergroup competition and cooperation, participants estimated the range of distributions among in‐ group and out‐group members regarding various traits. The central tendency and variability derived from each estimate were analysed. Members of the low status groups deprecated their in‐group with respect to a status‐defining trait, but showed in‐group favouritism regarding alternative, status‐irrelevant traits. Furthermore, the low status members judged their in‐group as more homogeneous than the out‐group regarding the alternative traits, particularly when they were compared to a high status group. The results were interpreted as an indication of a subtle form of maintaining positive in‐group evaluations. Theoretical and methodological implications for the study of status effects are discussed. Copyright © 2004 John Wiley & Sons, Ltd.     

Effects of semantic context and event-related potentials: N400 correlates with inhibition effect

Two experiments investigated the modulation of event-related brain potentials (ERPs) by semantic context. A prime-target pair was visually presented in each trial of a lexical decision task. For word targets, three types of relatedness conditions were employed: (1) Related word condition (e.g., school-teacher); (2) Neutral word condition (e.g., [symbol: see text] - number); (3) Unrelated word c((e.g., hospital-potato). In Experiment 1, the reaction time for unrelated targets was longer than that for neutral targets (inhibition effect) which was longer than that for related targets (facilitation effect). The N400 amplitude in the unrelated targets was larger compared to those in the related and neutral targets, which did not differ. In Experiment 2, where only the facilitation effect was obtained, the N400 amplitude did not differ among conditions.