Le role de la convention dans l'espace d'un observateur isolé

Sommaire L'édification spatio-temporelle dont se sert un observateur isolé pour représenter ses résultats de mesures comporte la construction d'un espace physique qui, quoique non catégorique, est applicable sur l'espace euclidien à trois dimensions. Aucun argument ne permet de décider si l'espace est euclidien ou non euclidien. Les expériences permettent seulement à l'observateur d'affirmer que l'espace est pratiquement euclidien en son voisinage.     

In Vivo Hippocampal Acetylcholine Release During Exposure to Acute Stress

Hippocampal extracellular acetylcholine (ACh) and choline levels were evaluated using in vivo microdialysis in male Fischer 344 rats before, during, and following an 80-min exposure to two different stress conditions. Measurements were taken in rats restrained and immersed in a water bath containing either 37 degreesC (normothermic-restraint) or 20 degreesC (cold-restraint) water. Results were compared to normothermic-freely-moving rats. Cold-restrained rats displayed decreased ACh levels during cold exposure relative to both normothermic-restrained and normothermic-freely-moving rats. By the end of the cold exposure period and following removal from cold, ACh levels had returned to near-baseline values. Normothermic-restrained rats had levels similar to those of normothermic-freely-moving rats, except for a marked increase in ACh following removal from restraint. Cold-restrained rats displayed a gradual elevation in choline levels during cold stress, followed by a gradual decline after stress termination, whereas both normothermic-restrained and normothermic-freely-moving rats displayed gradual decreases during the microdialysis session. These findings demonstrate that central cholinergic neurotransmission can be altered by the application of, and removal from, acute stressors. In addition, the results suggest a possible relationship between the magnitudes of both the stressor and its cholinergic consequences.     

One-session cognitive treatment of dental phobia: preparing dental phobics for treatment by restructuring negative cognitions

The purpose of this study was to investigate the effectiveness of a single session of cognitive restructuring in a sample of phobic dental patients. Fifty-two patients were randomly assigned to one of three conditions: cognitive restructuring (modification of negative cognitions), provision of information (about oral health and dental treatment), and a waiting list control condition. Both interventions maximally lasted one hour. In comparison with the waiting list control condition and the information intervention condition, the cognitive intervention condition not only showed a large decrease in frequency and believability of negative cognitions, but also exhibited a clear decline in dental trait anxiety. Analysis at a follow-up of one year demonstrated a further, drastic reduction in dental anxiety in both intervention conditions, wherein the difference among these conditions was not maintained. It is concluded that it is possible to obtain substantial reductions of dental trait anxiety through a single session of cognitive restructuring. Nevertheless, repeated exposure to the dental situation seems necessary for a further reduction of anxiety.     

Dissociation of implicit and explicit memory tests: Effect of age and divided attention on category exemplar generation and cued recall

In this article, we report an experiment that provides further evidence concerning the differences between explicit and implicit measures of memory. The effects of age and divided attention on the implicit conceptual test of category exemplar generation (CEG) were compared with their effects on the explicit test of cued recall, where the category names served as cues in both tasks. Four age groups (20–35, 40–55, 60–75, and 76–90) were compared. Half of the subjects were also required to carry out a secondary letter-detection task during the learning phase. Cued recall performance was significantly impaired by increased age and imposition of the secondary task. In contrast, the CEG task was unaffected by these two factors. These results suggest that implicit conceptual tasks and explicit memory tasks are mediated by different processes. This conclusion opposes those of previous studies that showed that experimental manipulations (level of processing, generation, organization) influenced these two kinds of memory tests in a similar way.     

Aspects of preschoolers' comprehension of indoor and outdoor gender-typed toys

Forty-nine 44- to 81-month-old predominantly white children's classification of and clustering in recall of gender-typed indoor and outdoor toys, and their gender schematicity, were assessed. Consistent with predictions, children high in gender schematicity demonstrated significantly greater clustering in their recall by gender type than children low in schematicity. As expected, all children demonstrated more accurate classification of same-sex than other-sex gender-typed toys in general. However, boys and girls showed distinctively different patterns in their abilities to accurately classify same-sex and other-sex indoor and outdoor gender-typed toys. Results are discussed in terms of the different social and play contexts inhabited by preschool boys and girls.Completion of this project was facilitated by funds received when the author was a National Institute of Mental Health Postdoctoral Fellow at the University of Denver; Grant 5T32 MH 15780-09, in addition to an Academic Challenge Award from the University of Toledo. This support is gratefully acknowledged. Special thanks to Maryjo Jones for her data collection efforts and to the faculty, children, and parents of Iliff Preschool of Denver, Colorado, and especially to Director Jean True for assisting in the completion of this research. Thanks also to Joan M. Barth, Narina N. Nightingale, Kathy A. Park, and Peg Hull-Smith for their comments on earlier versions of this article. A shorter version of this paper was presented at the Conference on Human Development, Richmond, Virginia, March 1990.To whom reprint requests should be addressed at Department of Psychology, University of Wyoming, P.O. Box 3415, Room 135 Biological Sciences Building, Laramie, WY 82071-3415.     

Long term marriages in Sweden: And some comparisons with similar couples in the United States

This international, five-country long term marriages study of couples who have been married, or unmarried and cohabiting, for 20 years or longer is designed to study, among other things, marital satisfaction. This first report of the Swedish part of the study reports on a Swedish version of the self-rating Dyadic Adjustment Scale (DAS) used to investigate self-rated marital satisfaction. The couples describe high marital satisfaction and a high sense of coherence (SOC) compared to other groups. Contrary to other studies, no differences were found between men and women regarding SOC. The differences between them, that describe high relative to low marital satisfaction, pertain to matters of recreation, sex, life philosophy, time spent together, and frequency of quarrels. The men reported greater marital satisfaction than the women.