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201.
Corina J. Logan Alexis J. Breen Alex H. Taylor Russell D. Gray William J. E. Hoppitt 《Learning & behavior》2016,44(1):18-28
New Caledonian crows make and use tools, and tool types vary over geographic landscapes. Social learning may explain the variation in tool design, but it is unknown to what degree social learning accounts for the maintenance of these designs. Indeed, little is known about the mechanisms these crows use to obtain information from others, despite the question’s importance in understanding whether tool behavior is transmitted via social, genetic, or environmental means. For social transmission to account for tool-type variation, copying must utilize a mechanism that is action specific (e.g., pushing left vs. right) as well as context specific (e.g., pushing a particular object vs. any object). To determine whether crows can copy a demonstrator’s actions as well as the contexts in which they occur, we conducted a diffusion experiment using a novel foraging task. We used a nontool task to eliminate any confounds introduced by individual differences in their prior tool experience. Two groups had demonstrators (trained in isolation on different options of a four-option task, including a two-action option) and one group did not. We found that crows socially learn about context: After observers see a demonstrator interact with the task, they are more likely to interact with the same parts of the task. In contrast, observers did not copy the demonstrator’s specific actions. Our results suggest it is unlikely that observing tool-making behavior transmits tool types. We suggest it is possible that tool types are transmitted when crows copy the physical form of the tools they encounter. 相似文献
202.
OBJECTIVE: This study compared recidivism rates for alleged maltreatment perpetrators whose initial report was substantiated and those whose initial report was not substantiated, to determine whether they returned to the child welfare system at differing rates. METHOD: Statewide administrative child welfare services data over a period of 4 1/2 years was analyzed. The sample included 31,531 perpetrators of intrafamilial maltreatment. Separate analyses were conducted for each type of maltreatment (sexual abuse, physical abuse, and neglect). RESULTS: Bivariate relationships (substantiation status and recidivism) were analyzed using survival curves, and the study found that recidivism patterns differed by type of maltreatment and by substantiation status at the index event. Multivariate analyses using Cox Proportional Hazards models found that bivariate relationships held true even when controlling for neighborhood mean income, ethnicity, and gender. CONCLUSIONS: The study's finding that perpetrators whose index event was not substantiated return to the child welfare system at a high rate suggests the need to learn how to discriminate those unsubstantiated alleged perpetrators who are most at risk for recidivism. The finding of frequent cross-type recidivism indicates that intervention should focus on common themes across maltreatment types. 相似文献
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This study was conducted to determine if a planning and writing strategy would improve the essay writing of students with learning disabilities. Four participants were taught a strategy designed to facilitate the setting of product and process goals, generation and organization of notes, continued planning during writing, and evaluation of goal attainment. Training effects were investigated using a multiple probe design across subjects. Strategy instruction had a positive effect on students' essay writing performance and knowledge of the writing process, and effects were maintained over time. 相似文献
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Spelling skills have been identified as one of the major barriers to written text production in young English writers. By contrast oral language skills and text generation have been found to be less influential in the texts produced by beginning writers. To date, our understanding of the role of spelling skills in transparent orthographies is limited. The current study addressed this gap by examining the contribution of spelling, oral language and text generation skills in written text production in Italian beginner writers. Eighty-three children aged 7–8 years participated in the study. Spelling, lexical retrieval, receptive grammar, and written sentence generation and reformulation skills were assessed and children were asked to write a text on a set topic. A factor analysis revealed that the children’s written text production was captured by three factors: productivity, complexity and accuracy. In contrast to results from children learning to write in opaque orthographies, such as English, this study showed that receptive grammar and written sentence generation skills accounted for significant variance in measures of productivity, complexity and accuracy in Italian children’s written text production. Spelling skills contributed to text accuracy and quality and explained more variance than receptive grammar in microstructural accuracy. By contrast, oral grammatical skills explained more variance in text quality than spelling. The current study shows the differential impact of language systems, such as Italian, on written text production. Implications for assessment and instruction are outlined. 相似文献
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Kindergarten, third-grade, and sixth-grade children were told 2 stories about a group of children who made artwork that was subsequently sold at a craft fair. The characters in one story were described as friends, while the characters in the other story were described as strangers (relationship condition). 1 character in each story was presented as the oldest in the group, 1 as the most productive, and 1 as the poorest. Children were asked to allocate 9 dollars to the 3 characters under each relationship condition, provide rationales for those allocations, and rate the fairness of 4 different patterns of allocation. Older children allocated more money to needy friends than to needy strangers and more to productive strangers than to productive friends. Kindergartners' allocations and fairness ratings did not vary with relationship. Rationales for allocation judgements suggested that equality was the most salient principle for decisions at all ages, but the older children provided rationales based on benevolence more often than younger children when characters were presented as friends. 相似文献
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The term noise is used to describe fluctuations about the mean deterministic stationary value of a physical quantity. It is
now being increasingly realised that noise is an important ingredient to bring order in dynamical processes. Though it appears
counterintuitive, noise seems to help in directing transport processes in biological systems at the molecular level. In Part
2 of the article, we discuss some more examples of noise assisted directed motion. 相似文献