Concreteness fading in learning secondary school physics concepts

Concreteness fading has been proposed as a general instructional approach to support learning of abstract mathematics and science concepts. Accordingly, organizing external knowledge representations in a three-step concrete-to-idealized sequence should be more beneficial than the reverse, concreteness introduction, sequence. So far, evidence for the benefits of concreteness fading come mainly from studies investigating learning of basic mathematics concepts. Studies on learning natural science concepts are scarce and have not implemented the full three-step-sequence. In an experimental classroom study (N = 70), we compared concreteness fading and concreteness introduction in high school science education about electromagnetic induction using a detailed assessment. Furthermore, we explored whether these sequences differentially affect the use of the different representations during instruction. Both sequences were equally effective and there were no differences in using the representations. We discuss why our results question the proposed advantages of concreteness fading and highlight conceptual differences and learning goals across domains.     

Effect of binocular disparity on learning anatomy with stereoscopic augmented reality visualization: A double center randomized controlled trial

Binocular disparity provides one of the important depth cues within stereoscopic three-dimensional (3D) visualization technology. However, there is limited research on its effect on learning within a 3D augmented reality (AR) environment. This study evaluated the effect of binocular disparity on the acquisition of anatomical knowledge and perceived cognitive load in relation to visual-spatial abilities. In a double-center randomized controlled trial, first-year (bio)medical undergraduates studied lower extremity anatomy in an interactive 3D AR environment either with a stereoscopic 3D view (n = 32) or monoscopic 3D view (n = 34). Visual-spatial abilities were tested with a mental rotation test. Anatomical knowledge was assessed by a validated 30-item written test and 30-item specimen test. Cognitive load was measured by the NASA-TLX questionnaire. Students in the stereoscopic 3D and monoscopic 3D groups performed equally well in terms of percentage correct answers (written test: 47.9 ± 15.8 vs. 49.1 ± 18.3; P = 0.635; specimen test: 43.0 ± 17.9 vs. 46.3 ± 15.1; P = 0.429), and perceived cognitive load scores (6.2 ± 1.0 vs. 6.2 ± 1.3; P = 0.992). Regardless of intervention, visual-spatial abilities were positively associated with the specimen test scores (η² = 0.13, P = 0.003), perceived representativeness of the anatomy test questions (P = 0.010) and subjective improvement in anatomy knowledge (P < 0.001). In conclusion, binocular disparity does not improve learning anatomy. Motion parallax should be considered as another important depth cue that contributes to depth perception during learning in a stereoscopic 3D AR environment.     

不同迁移方式与不同学习“方式”对知觉运动序列学习的影响——一项ERP研究

拟采用迁移范式,以事件相关电位(ERP)成分N2、P3作为主要指标,结合不同迁移方式和不同学习方式探讨学习者的知识表征方式的差异。结果发现:内隐组和外显组被试在习得了一定的序列知识后,相对于标准序列的反应时,效应器迁移序列的反应时明显变慢;在脑电数据中,以N2的平均波幅作为指标,不管是内隐组还是外显组,标准序列与刺激迁移序列不存在区别,而与效应器迁移序列却差异显著。对于P3的平均波幅的分析得出:在内隐组,标准序列与效应器迁移序列不存在区别;而在外显组,两者却差异显著。该结果说明:效应器水平的编码机制是参与序列知识的学习的;且相对于知觉编码,不管以何种方式学习,效应器编码起的作用都要更大。     

Characterization of two-dimensional cellular automata over ternary fields

The set of papers [3], [4], [6] and [7] (Chattopadhyay et al., 1999; Dihidar and Choudhury, 2004; Khan et al., 1997, 1999) deals with the behavior of the uniform two-dimensional cellular automata over binary fields (Z₂). Some structural properties and precise mathematical models using matrix algebra over the field Z₂ are reported for characterizing the behavior of two-dimensional nearest neighborhood linear cellular automata with null and periodic boundary conditions [3], [4], [6] and [7] (Chattopadhyay et al., 1999; Dihidar and Choudhury, 2004; Khan et al., 1997, 1999). In this paper, we characterize two-dimensional linear cellular automata transformations by using matrix algebra built on Z₃. We analyze some results for two-dimensional CA with rule numbers 2460N and 2460P. Finally, we investigate the dimension of the kernel of two-dimensional cellular automata defined by the rule number 2460N.     

Public discourse on HIV and AIDS: an archival analysis of national newspaper reporting in Uganda, 1996–2011

Uganda is recognised as an early success story in the HIV epidemic at least in part due to an open and vigorous national dialogue about HIV prevention. This study examined the national discourse about HIV, AIDS, and young people in New Vision, Uganda's leading national newspaper between 1996 and 2011, building from a previous archival analysis of New Vision reporting by Kirby (1986–1995). We examined the continuing evolution in the public discourse in Uganda, focusing on reporting about young people. An increase in reporting on HIV and AIDS occurred after 2003, as antiretroviral treatment was becoming available. While the emphasis in newspaper reporting about adults and the population at large evolved to reflect the development of new HIV treatment and prevention methods, the majority of the articles focused on young people did not change. Articles about young people continued to emphasise HIV acquisition due to early and premarital sexual activity and the need for social support services for children affected by HIV and AIDS. Articles often did not report on the complex social conditions that shape HIV-related risk among young people, or address young people who are sexually active, married, and/or HIV-infected. With HIV prevalence now increasing among young people and adults in Uganda, greater attention to HIV prevention is needed.     

国外关于数学学习中多元外在表征的研究述评

20世纪80年代以来,随着现代信息技术在教育领域的应用,多元外在表征的研究成了认知科学、教育技术、教育心理学等领域的热门话题.数学学习中多元外在表征的研究主要趋势是:综合运用多种理论和多种研究方法,深入探讨多元外在表征研究对数学学习的价值与意义,建构数学学习中多元表征研究的基本理论;系统思考各种因素探讨运用多元外在表征的教学设计,提高学习效率.     

Juridification of examination systems: extending state level authority over teacher assessments through regrading of national tests

Since 2009, the Swedish Government uses an ‘audit’ agency – the Swedish Schools Inspectorate – to monitor and assess the accuracy with which teachers grade student responses on national tests. This study explores the introduction and subsequent establishment of the Inspectorate’s regrading programme as an example of political management of the tensions between competition and equity inherent in neoliberal regulatory regimes. The programme is considered a case for examining contemporary policies and discourses on fairness and government actions undertaken to resolve issues of unfair assessment and safeguard students’ rights. Work of Carol Bacchi forms part of the theoretical background for the investigation of problem representations around and within the programme. The article demonstrates how discursive practices in the fields of government, audit and media have worked to frame teachers’ assessments as incorrect, unfair and as jeopardizing the credibility of the grading system, thus justifying increased central control and authority over teacher assessments. As such, the regrading programme contributed to increased mistrust in teacher professionalism. A legal discourse is identified, and we argue the examination system is being juridified where the abundance of control over knowledge risks turning into a deficit of that same knowledge.     

The pedagogical potential of drawing and writing in a primary science multimodal unit

In consideration of the potential of drawing and writing as assessment and learning tools, we explored how early primary students used these modes to communicate their science understandings. The context for this study was a curricular unit that incorporated multiple modes of representation in both the presentation of information and production of student understanding with a focus on the structure and function of carnivorous plants (CPs). Two science teacher educators and two first-grade teachers in the United States co-planned and co-taught a multimodal science unit on CP structure and function that included multiple representations of Venus flytraps (VFTs): physical specimens, photographs, videos, text, and discussions. Pre- and post-assessment student drawings and writings were statistically compared to note significant changes, and pre- and post-assessment writings were qualitatively analysed to note themes in student ideas. Results indicate that students increased their knowledge of VFT structure and function and synthesised information from multiple modes. While students included more structures of the VFT in their drawings, they were better able to describe the functions of structures in their writings. These results suggest the benefits for student learning and assessment of having early primary students represent their science understandings in multiple modes.