The role of trial tracking in rats’ working memory     

J. S. Cohen  M. Njegovan 《Learning & behavior》1999,27(2):211-220

The experiments reported in the present study tested whether decreasing intertrial intervals (ITIs) intensifies the disruptive effects of increasing retention intervals (RIs) in a delayed conditional discrimination by decreasing the animal’s trial tracking accuracy (Cohen & Armstrong, 1996; Cohen & Roberts, 1996). Rats responded on a fixed ratio (FR) 1 or fixed interval (FI) 10-sec reinforcement schedule at a second light or tone stimulus, S2, when the first light or tone stimulus, S1, had signaled an FI 10-sec or FR 1 schedule, respectively. RIs between S1 and S2 were increased from 3 to 24 sec and never exceeded ITIs that were reduced from 24 to 6 sec. For some rats, the trials were separated from each other by extending the lever at S1 and retracting it at the end of S2 (ITI lever-retracted group). For other, control rats, the lever remained extended throughout the session (lever-extended group, Experiment 1) or was extended and retracted with the onset and offset of each stimulus (RI/ITI lever-retracted group, Experiment 2). The rats under all trial conditions learned to delay leverpressing on the FI 10-sec schedule. Latency to begin leverpressing on the FI 10-sec schedule declined as RIs were increased, but this effect was attenuated in the ITI lever-retracted groups in both experiments, as would be predicted by thetrial tracking hypothesis. Decreasing ITIs from 24 to 6 sec intensified the disruptive effects of increasing RIs from 3 to 6 sec in the RI/ITI lever-retracted group (Experiment 2), as would be predicted by the trial tracking hypothesis.  相似文献   

Simplifying Algebraic Expressions: Teacher Awareness and Teaching Approaches     

Dina Tirosh  Ruhama Even  Naomi Robinson 《Educational Studies in Mathematics》1998,35(1):51-64

This study investigates four seventh-grade teachers' awareness of students' tendency to conjoin or 'finish' open expressions. It also investigates teachers' ways of coping with this tendency. Three types of data were collected: 1) lesson plans, 2) lesson observations, and 3) post-lesson interviews. The analysis showed that the two experienced teachers were aware of this tendency and some of its possible sources, while the novices were unaware of either. Teaching approaches related to this tendency also differed considerably. In conclusion we analyze these teaching methods in light of the existing literature and discuss possible short- and long-term implications of the use of each approach.  相似文献   

Making Sense of Number Words and Arabic Digits: Does Order Count More?     

Francesco Sella  Daniela Lucangeli  Roi Cohen Kadosh  Marco Zorzi 《Child development》2020,91(5):1456-1470

The ability to choose the larger between two numbers reflects a mature understanding of the magnitude associated with numerical symbols. The present study explores how the knowledge of the number sequence and memory capacity (verbal and visuospatial) relate to number comparison skills while controlling for cardinal knowledge. Preschool children’s (N = 140, M_{age-in-months} = 58.9, range = 41–75) knowledge of the directional property of the counting list as well as the spatial mapping of digits on the visual line were assessed. The ability to order digits on the visual line mediated the relation between memory capacity and number comparison skills while controlling for cardinal knowledge. Beyond cardinality, the knowledge of the (spatial) order of numbers marks the understanding of the magnitude associated with numbers.  相似文献   

Examining type I error and power for detection of differential item and testlet functioning     

Young-Sun Lee  Allan Cohen  Maritsa Toro 《Asia Pacific Education Review》2009,10(3):365-375

In this study, the effectiveness of detection of differential item functioning (DIF) and testlet DIF using SIBTEST and Poly-SIBTEST were examined in tests composed of testlets. An example using data from a reading comprehension test showed that results from SIBTEST and Poly-SIBTEST were not completely consistent in the detection of DIF and testlet DIF. Results from a simulation study indicated that SIBTEST appeared to maintain type I error control for most conditions, except in some instances in which the magnitude of simulated DIF tended to increase. This same pattern was present for the Poly-SIBTEST results, although Poly-SIBTEST demonstrated markedly less control of type I errors. Type I error control with Poly-SIBTEST was lower for those conditions for which the ability was unmatched to test difficulty. The power results for SIBTEST were not adversely affected, when the size and percent of simulated DIF increased. Although Poly-SIBTEST failed to control type I errors in over 85% of the conditions simulated, in those conditions for which type I error control was maintained, Poly-SIBTEST demonstrated higher power than SIBTEST.  相似文献   

Tasks, topics and relevance judging for the TREC Genomics Track: five years of experience evaluating biomedical text information retrieval systems     

Phoebe M. Roberts  Aaron M. Cohen  William R. Hersh 《Information Retrieval》2009,12(1):81-97

With the help of a team of expert biologist judges, the TREC Genomics track has generated four large sets of “gold standard” test collections, comprised of over a hundred unique topics, two kinds of ad hoc retrieval tasks, and their corresponding relevance judgments. Over the years of the track, increasingly complex tasks necessitated the creation of judging tools and training guidelines to accommodate teams of part-time short-term workers from a variety of specialized biological scientific backgrounds, and to address consistency and reproducibility of the assessment process. Important lessons were learned about factors that influenced the utility of the test collections including topic design, annotations provided by judges, methods used for identifying and training judges, and providing a central moderator “meta-judge”.  相似文献   

政策和实践的困境(下)     

大卫·K·科恩  苏珊·L·莫菲特  西蒙娜·戈尔丁 《华东师范大学学报(教育科学版)》2010,28(4):1-9

教育政策和实践总是处在困境之中,这是困扰政策制定者和实践者的问题.本文着力从教育政策和实践所面临的困境、如何处理困境的角度,重新审视政策和实践两者的关系,并从政策目标、政策工具和实践中的能力三方面对其展开论述,以期在冲突的基础上促进教育政策和实践间的融合.  相似文献   

Science Teachers’ Professional Development and Changes in Science Practical Assessment Practices: What are the Issues?   总被引：1，自引：0，他引：1  

Phillip A. Towndrow  Aik-Ling Tan  Benny H. W. Yung  Libby Cohen 《Research in Science Education》2010,40(2):117-132

This paper considers the circumstances under which science teachers can respond positively and productively to educational policy reforms in the area of science practical assessment. To understand what might be involved in linking science teachers’ assessment capacities and their professional development, we present illustrative data from recent research studies conducted in Singapore and Hong Kong showing contrasting approaches taken in the implementation of reforms in science practical assessment. In Singapore, teachers worked together to select, discuss, clarify and refine their practices as they made decisions about what to teach and assess. In Hong Kong, teachers took a critical stance towards the new policy and learnt from their own experiences in order to build their confidence. With the same policy initiative, one group of teachers focused more on the technicalities of complying with requirements imposed on them while in the other group had their professional consciousness of what they thought was best for their students provoked so that their practices would be transformed. In an attempt to draw lessons for other contexts in supporting the implementation of assessment policy reforms through professional development work, we identify and discuss a range of factors in science teachers’ professional development that arise once in situ professional development work has started. Overall, our intent in this article is to recast assessment reform as a driver or pivot in teachers’ professional development and learning. To do this it is necessary, we argue, to afford teachers’ experiences and the processes involved in learning from them greater emphasis in order to ensure the continuance of innovation in the assessment of laboratory-based work.  相似文献   

A New Compact for Higher Education: Funding and Autonomy for Reform and Accountability     

James M. Kallison  Philip Cohen 《Innovative Higher Education》2010,35(1):37-49

Over the past few decades, America’s social compact for higher education as a public good has effectively lapsed as government support of higher education has diminished. Given the need for a highly educated workforce in today’s knowledge-based global economy, we propose a new compact for higher education that couples increased funding with increased institutional accountability. While the compact must retain academic freedom as an essential component of higher education, this autonomy must co-exist with rigorous accountability standards. Accountability systems should be multifaceted, as different methodologies have differing strengths and limitations. All systems should, however, inform the public and provide for institutional improvement.  相似文献   

Age versus schooling effects on intelligence development   总被引：1，自引：0，他引：1  

S Cahan  N Cohen 《Child development》1989,60(5):1239-1249

The effect of formal education, as opposed to chronological age, on intelligence development has suffered from inadequate empirical investigation. Most studies of this issue have relied on natural variation in exposure to school among children of the same age, thus confounding differences in schooling with differences in other intelligence-related variables. This difficulty can be overcome by a quasi-experimental paradigm involving comparison between children who differ in both chronological age and schooling. The present study applies this paradigm to the estimation of the independent effects of age and schooling in grades 5 and 6 on raw scores obtained on a variety of general ability tests. The sample included all students in Jerusalem's Hebrew-language, state-controlled elementary schools. The results unambiguously point to schooling as the major factor underlying the increase of intelligence test scores as a function of age and to the larger effect schooling has on verbal than nonverbal tests. These results contribute to our understanding of the causal model underlying intelligence development and call for reconsideration of the conceptual basis underlying the definition of deviation-IQ scores. Some implications of these results concerning the distinction between intelligence and scholastic achievement, the causal model underlying the development of "crystallized" and "fluid" abilities, and the notion of "culture-fair" tests are discussed.  相似文献   

Developmental change in infants' perception of correlations among attributes   总被引：3，自引：0，他引：3  

B A Younger  L B Cohen 《Child development》1986,57(3):803-815

The perception of relational information such as the correlation or co-occurrence among features should play a central role in abilities ranging from the perception and recognition of a simple pattern or object to the formation of a category. 4 experiments were conducted to examine developmental change in 4-, 7-, and 10-month-old infants' perception of correlations among attributes. The results suggested a developmental progression in infants' processing of simple correlational information, ranging from the processing of independent featural information only at 4 months, the perception of relations among features of a single pattern at 7 months, to the abstraction of invariant relations from a category at 10 months.  相似文献