The perception of minimal structures: performance on open and closed versions of visually presented Euclidean travelling salesperson problems

The planar Euclidean version of the travelling salesperson problem (TSP) requires finding a tour of minimal length through a two-dimensional set of nodes. Despite the computational intractability of the TSP, people can produce rapid, near-optimal solutions to visually presented versions of such problems. To explain this, MacGregor et al (1999, Perception 28 1417-1428) have suggested that people use a global-to-local process, based on a perceptual tendency to organise stimuli into convex figures. We review the evidence for this idea and propose an alternative, local-to-global hypothesis, based on the detection of least distances between the nodes in an array. We present the results of an experiment in which we examined the relationships between three objective measures and performance measures of optimality and response uncertainty in tasks requiring participants to construct a closed tour or an open path. The data are not well accounted for by a process based on the convex hull. In contrast, results are generally consistent with a locally focused process based initially on the detection of nearest-neighbour clusters. Individual differences are interpreted in terms of a hierarchical process of constructing solutions, and the findings are related to a more general analysis of the role of nearest neighbours in the perception of structure and motion.     

Influence of the teacher-student relationship on childhood conduct problems: a prospective study.

Examined the influence of the quality of the teacher-student relationship on children's subsequent levels of aggression in a sample of 61 second and third-grade children nominated and rated by their teachers as aggressive. The stability of teachers' and children's reports of relationships quality across academic years was in the low to moderate range. Teachers and children showed little agreement in their reports of relationship quality. Teachers' and children's reports of relationship quality in year 1 (Y1) predicted teacher-rated aggression the following year, controlling for Y1 ratings of aggression. Teachers' reports of relationship quality across Y1 and Y2 predicted peer-rated aggression, but not teacher-rated aggression, in Y3, controlling for Y1 aggression. Consistent with a buffering role for teacher-student relationships, a positive teacher-student relationship was of greatest benefit to children whose mothers reported rejecting parenting histories. We discuss implications for school-based prevention programs.     

United we stand, divided we fall: the education and training needs of clinical child psychologists

Reviews efforts to delineate training needs for psychologists who are providing clinical services to children, adolescents, and families. In particular, this article (a) describes efforts of clinical child and other psychologists who work with children, adolescents, and families to develop education and training guidelines; (b) discusses the overlap among various child and adolescent providers within psychology; and (c) highlights several key competencies that have been identified as important for all psychologists in practice roles with children and adolescents. In particular, we emphasize the need for greater collaboration and integration among various psychological specialties that focus on children, adolescents, and families and for greater system-wide discussion of training needs and priorities.     

Evidence for abstract, schematic knowledge of three spatial diagram representations

Spatial diagram representations such as hierarchies, matrices, and networks are important tools for thinking. Our data suggest that college students possess abstract schemas for these representations that include at least rudimentary information about their applicability conditions. In Experiment 1, subjects were better able to select the appropriate spatial diagram representation for a problem when cued to use general category information in memory about those representations than when cued to use specific example problems given during the experiment. The results of Experiment 2 showed that the superior performance in the general category condition was not based on a comparison of the test problems with examples in memory. The results of Experiment 3 showed that the superior performance was not due to learning that occurred during the experiment or to transfer appropriate processing. The General Discussion section considers the nature of students' representation schemas and the question of why college students have only rudimentary schemas for common and widely applicable diagrammatic representations.     

State and Society in the Political Thought of the Moscow Slavophiles

Leading members of the Slavophile circle shared a commonWeltanschauung, fostered by a complex reaction to thesocial and political changes taking place in mid-nineteenth-centuryRussia. There was, however, considerable diversity in their views aboutthe character and value of the Russian state apparatus. While theyall criticised the bureaucratic ethos of the tsarist state,a number of them recognised that it played a critical role in stabilising deep-seated social tensions in Russian society. Inthe late 1850s, some members of the Slavophile circle also cameto recognise that the state apparatus could play a positiverole in eliminating serfdom. Nevertheless, in the wake ofthe Emancipation Edict of 1861, conflict over the roleof the Russian state became the most divisive issuefor surviving members of the Slavophile circle.