632 research outputs found

    Driving under the influence of risky peers : an experimental study of adolescent risk taking.

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    Both passive and active social influences may affect adolescents' dangerous driving. In this study, we used an experimental paradigm to delineate these two influences with actual peers. Adolescents completed a simulated driving task, and we measured risk preferences of each member of the peer group. We used hierarchical linear modeling to partition variance in risky decisions. Adolescents experienced many more crashes when they had “passengers” present who reported a strong preference for risk taking and who actively provided decision-making guidance. Although youth in the passive peer condition were also influenced by the riskiness of their peers, this relation was less strong relative to the active condition. We discuss the need for interventions focussing on active and passive peer influence

    Helping education undergraduates to use appropriate criteria for evaluating accounts of motivation

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    The aim of the study was to compare students in a control group with those in a treatment group with respect to evaluative comments on psychological accounts of motivation. The treatment group systematically scrutinized the nature and interpretation of evidence that supported different accounts, and the assumptions, logic, coherence and clarity of accounts. Content analysis of 74 scripts (using three categories) showed that the control group students made more assertions than either evidential or evaluative points, whereas the treatment group used evaluative statements as often as they used assertion. The findings provide support for privileging activities that develop understanding of how knowledge might be contested, and suggest a need for further research on pedagogies to serve this end. The idea is considered that such understanding has a pivotal role in the development of critical thinking

    Representing addition and subtraction : learning the formal conventions

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    The study was designed to test the effects of a structured intervention in teaching children to represent addition and subtraction. In a post-test only control group design, 90 five-year-olds experienced the intervention entitled Bi-directional Translation whilst 90 control subjects experienced typical teaching. Post-intervention testing showed some significant differences between the two groups both in terms of being able to effect the addition and subtraction operations and in being able to determine which operation was appropriate. The results suggest that, contrary to historical practices, children's exploration of real world situations should precede practice in arithmetical symbol manipulation

    A simple radionuclide-driven single-ion source

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    We describe a source capable of producing single barium ions through nuclear recoils in radioactive decay. The source is fabricated by electroplating 148Gd onto a silicon {\alpha}-particle detector and vapor depositing a layer of BaF2 over it. 144Sm recoils from the alpha decay of 148Gd are used to dislodge Ba+ ions from the BaF2 layer and emit them in the surrounding environment. The simultaneous detection of an {\alpha} particle in the substrate detector allows for tagging of the nuclear decay and of the Ba+ emission. The source is simple, durable, and can be manipulated and used in different environments. We discuss the fabrication process, which can be easily adapted to emit most other chemical species, and the performance of the source
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