Mechanism-based causal reasoning in young children

The hypothesis that children develop an understanding of causal mechanisms was tested across 3 experiments. In Experiment 1 (N = 48), preschoolers had to choose as efficacious either a cause that had worked in the past, but was now disconnected from its effect, or a cause that had failed to work previously, but was now connected. Four-year-olds chose the now-connected cause more often than 3-year-olds. Experiment 2 (N = 16) showed 4-year-olds responded appropriately to an irrelevant modification in the same causal system. Experiment 3 (N = 24) demonstrated when the mechanism was batteries rather than connection, 3-year-olds could properly distinguish between relevant and irrelevant modifications. Together, these data suggest that understanding of specific causal mechanisms develops at different ages.     

Discrepancies in accelerometer-measured physical activity in children due to cut-point non-equivalence and placement site

Abstract This study examined dissonance in physical activity (PA) between two youth-specific hip-derived intensity cut-points for the Actiwatch (AW), and compared PA between hip and wrist placements using site-specific cut-points. Twenty-four children aged 11.2?±?0.5 years wore the AW on the right hip and non-dominant wrist during a typical school day. Minutes of sedentary behaviour and vigorous activity were greater using Puyau et al. (2002) cut-points, but light, moderate, and moderate-to-vigorous (MVPA) were greater when derived using Puyau et al. (2004) cut-points (P?相似文献   

The transfer of U.S. technology abroad

The causes of the transfer of technology between countries is now seen as an important dimension of the diffusion of new products and processes. Despite its obvious importance, there has been little empirical research investigating the international transfer of technology, although the work of Schiffel and Kitti (Research Policy 7 (1978)) provides a useful foundation on which to build. The research reported below tests the hypothesis that the transfer of technology between countries, as measured by the movement of patented invention, is influenced by both supply side and demand side factors. The principal variables are: patenting activity in the country of origin; the size of the recepient economy; international trade in goods and services; and the operations of multinational producing enterprises. These vaiables explain most of the variation across countries in the transfer of U.S. technology abroad. The worldwide distribution of U.S. based multinational enterprises appear to play an important part in explaining U.S. technology tranfer. On the other hand, the remaining international differences in patent law do not seem to significantly affect patent flows between countries.     

The evolution of an effective pedagogy for teachers using the interactive whiteboard in mathematics and modern languages: an empirical analysis from the secondary sector

There has been considerable investment in the use of interactive whiteboard technology in schools in the UK. There is evidence that whilst teachers understand such technology, many do not understand the nature and implications of interactive learning. Observation and analysis of 50 video‐recorded lessons taught by ‘successful’ teachers drawn from mathematics and modern foreign language departments in secondary schools led to the classification of three types of practice representing a spectrum of increasing interactivity. The nature of this good practice was analysed together with criteria for assessing the changes being wrought by technology in approaches to learning and teaching. The investigation concluded that the use of new technology alone cannot lead to enhanced learning. Teachers also need training to develop awareness of the relationship between approaches to interactive learning and conceptual and cognitive development in subject areas.     

Mental Calculation Methods Used By 11-Year-Olds in Different Attainment Bands: a reanalysis of data from the 1987 APU survey in the UK

This paper describes thereanalysis of data obtained in 1987 on themental calculation strategies used by asample of 11-year-olds in the course of anational survey of schools in England,Wales and Northern Ireland. The mentalskills test was administered to pupils in aone-to-one situation and the reanalysismade use of classifications of mentalstrategies developed in the past decade ininternational research. These pupils werea subsample of the main sample of about 10000 who took a written test of mathematicsin the survey, 247 taking both tests. Thescores on the written test were used todistribute these pupils into three bands ofattainment in order to compare thefrequency and effectiveness of thestrategies used by pupils of differentlevels of attainment. Eight of thereanalysed questions are discussed, each ofthem involving one of the four basicarithmetic operations. Some are purelynumerical and in others the numbers are ina context. Top band pupils mostly preferredsequential strategies which leave one ofthe numbers in the calculation complete,while the Bottom band generally preferredto split complete numbers and operateseparately on the components of the numbersthus partitioned. The most popularstrategy for Middle band pupils in severalquestions was the standard algorithm usedmentally. Complete number strategies werethe most successful for pupils in all threebands. Possible implications for theNational Numeracy Strategy in Britain arediscussed. This revised version was published online in July 2006 with corrections to the Cover Date.