The relation of multiple-schedule behavioral contrast to deprivation,time in session,and within-session changes in responding

Pigeons' keypecking was reinforced by food on baseline schedules of multiple variable interval (VI) x VI x and on contrast schedules of multiple VI x VI y. Deprivation of food was varied by maintaining subjects at 75%, 85%, and 95% (+/- 2%) of their free-feeding weights. Positive and negative behavioral contrast were observed. The size of the contrast was not systematically altered by changes in deprivation. Positive and negative contrast were both larger later in the session than they were earlier. Within-session decreases in responding were steeper for the baseline than for the contrast schedules for positive contrast. Within-session decreases were steeper for the contrast than for the baseline schedules for negative contrast. These results were predicted by the idea that different amounts of habituation to the reinforcer during the baseline and contrast schedules contribute to behavioral contrast. The results show that contrast occurs under conditions that reduce the effect of the following component. The results support the assumption that positive and negative contrast are produced by symmetrical theoretical variables.     

Designing Instructional Examples to Reduce Intrinsic Cognitive Load: Molar versus Modular Presentation of Solution Procedures

It is usually assumed that successful problemsolving in knowledge-rich domains depends onthe availability of abstract problem-typeschemas whose acquisition can be supported bypresenting students with worked examples.Conventionally designed worked examples oftenfocus on information that is related to themain components of problem-type schemas, namelyon information related to problem-categorymembership, structural task features, andcategory-specific solution procedures. However,studying these examples might be cognitivelydemanding because it requires learners tosimultaneously hold active a substantial amountof information in working memory. In ourresearch, we try to reduce intrinsic cognitiveload in example-based learning by shifting thelevel of presenting and explaining solutionprocedures from a `molar' view – that focuseson problem categories and their associatedoverall solution procedures – to a more`modular' view where complex solutions arebroken down into smaller meaningful solutionelements that can be conveyed separately. Wereview findings from five of our own studiesthat yield evidence for the fact thatprocessing modular examples is associated witha lower degree of intrinsic cognitive load andthus, improves learning.     

Impact of brief or extended extinction of a taste aversion on inhibitory associations: Evidence from summation,retardation, and preference tests

In five conditioned taste aversion experiments with rats, summation, retardation, and preference tests were used to assess the effects of extinguishing a conditioned saccharin aversion for three or nine trials. In Experiment 1, a summation test showed that saccharin aversion extinguished over nine trials reduced the aversion to a merely conditioned flavor (vinegar), whereas three saccharin extinction trials did not subsequently influence the vinegar aversion. Experiment 2 clarified that result, with unpaired controls equated on flavor exposure prior to testing; the results with those controls suggested that the flavor extinguished for nine trials produced generalization decrement during testing. In Experiment 3, the saccharin aversion reconditioned slowly after nine extinction trials, but not after three. Those results suggested the development of latent inhibition after more than three extinction trials. Preference tests comparing saccharin consumption with a concurrently available fluid (water in Experiment 4, saline in Experiment 5) showed that the preference for saccharin was greater after nine extinction trials than after three. However, saccharin preference after nine extinction trials was not greater, as compared with that for either latent inhibition controls (Experiments 4 and 5) or a control given equated exposures to saccharin and trained to drink saline at a high rate prior to testing (Experiment 5). Concerns about whether conditioned inhibition has been demonstrated in any flavor aversion procedure are discussed. Our findings help explain both successes and failures in demonstrating postextinction conditioned response recovery effects reported in the conditioned taste aversion literature, and they can be explained using a memory interference account.     

Towards Research-based Innovation and Reform: Singapore schooling in transition

The challenges facing the Singapore education system in the new millennium are unique and unprecedented in Asia. Demands for new skills, knowledges, and flexible competencies for globalised economies and cosmopolitan cultures will require system-wide innovation and reform. But there is a dearth of international benchmarks and prototypes for such reforms. This paper describes the current Core Research Program underway at the National Institute of Education in Singapore, a multilevel analysis of Singaporean schooling, pedagogy, youth and educational outcomes. It describes student background, performance, classroom practices, student artefacts and outcomes, and student longitudinal life pathways. The case is made that a systematic focus on teachers' and students' work in everyday classroom contexts is the necessary starting point for pedagogical innovation and change. This, it is argued, can constitute a rich multidisciplinary evidence base for educational policy.     

Revealing future research capacity from an analysis of a national database of discipline-coded Australian PhD thesis records

This article reports how statistical analyses of PhD thesis records can reveal future research capacities for disciplines beyond their primary fields. The previous research showed that most theses contributed to and/or used methodologies from more than one discipline. In Australia, there was a concern for declining mathematical teaching and research capacity. We decided to investigate the ‘hidden’ mathematics research capacity in PhDs outside of mathematics. Australian PhD records were re-coded with up to three fields. Records with mathematics as one of their codes were selected and analysed for their relationships to disciplines in their other codes. Triple-coding revealed ‘hidden’ mathematical research capacity that had previously been single-coded in another field had mathematics as one of their subsequent fields. Our findings have implications for policy and planning for mathematics in Australia, and multiple coding of PhD theses records enables analyses for other disciplines to be undertaken to show their research capacities.     

师生冲突的概念界定与分类探究——基于刘易斯·科塞的冲突分类理论

论文通过借鉴和辨析社会学理论中的冲突概念,对师生冲突概念作出界定。根据美国当代社会学家刘易斯·科塞的冲突分类理论,对学校师生冲突进行分类研究。在此基础上提出了三个观点:学校师生冲突的多数属于非现实性冲突;师生结构由紧密走向松散是师生冲突增多的重要原因;师生冲突具有一定的正面功能。     

Land degradation,government subsidy,and smallholders’ conservation decision: the case of the loess plateau in China

Land degradation is one of the severe environmental problems in China. In order to combat land degradation, a soil conservation program was introduced since 2000 to reduce soil erosion by converting slope-cultivated land into forestry and pasture. This paper represents the first systematic attempt to investigate the impact of the soil conservation program on land degradation in the loess plateau. The results indicate that the soil conservation program to convert slope fields into forest or pasture is an effective way to combat soil erosion. However, a subsidy that is higher than profit of land use activity of slope fields before their conversion into forest and pasture is needed to encourage farmers to join the conservation program. A policy measure to encourage and assist farmers to develop sedentary livestock by using crops produced from fields as well as fodder and forage grass from the converted slope fields might contribute to combat soil erosion. Increase in off-farm job opportunities may encourage households to reduce cultivation in slope fields. That implies a policy measure to encourage rural urbanization might contribute to combat soil erosion.     

Analysis of instruction for critical thinking in distance learning materials

This paper discusses procedures for the analysis of instructional strategies incorporated into distance learning materials, especially with regard to the development of the higher order cognitive ability—critical thinking. It examines the function of task analysis as an integral part of the instructional design process, analysing three different approaches available to the instructional designer towards the analysis of tasks required of distance learners. Comparing the learning hierarchy, the concept hierarchy, and the information processing approaches, it was found that the latter was the only one suitable for this current study because of the requirement that critical thinking be linked with domain‐specific knowledge, rather than be learned as an independent ability. Different algorithms for both the student and the designer/analyst are included as part of the information processing approach, and, although these methods are yet to be validated, they seem to offer sufficient promise, while allowing the analyst to make further decisions during the analysis.