As Time Goes By: Children''s Early Understanding of Growth in Animals

Beliefs about naturally occurring transformations were examined in children aged 3 to 6 years in 4 experiments. Experiment 1 tested children's understanding that animals (but not artifacts) predictably get larger over time. Experiment 1a examined whether the results obtained in the first experiment could be attributed to an added memory component on the artifact task. Experiment 2 further examined beliefs about the aging of artifacts. In Experiment 3, color and shape (metamorphosis) changes of animals were investigated. At all ages, children appeared to understand that animals get larger and not smaller with age. While older children and adults allowed for rather dramatic changes in the size and shape of animals over the life span if the alternative involved decreasing in size with age, preschool children were less willing to accept these changes. Taken together, the results of these studies suggest that even young preschool children have 2 conceptual insights about natural transformations: that they are lawful and nonrandom, and that they are domain and mechanism specific. Further, children as young as age 3 are able to go beyond the perceptual appearance of animals in making judgments about transformations caused by growth. Implications for children's understanding of personal and species identity are discussed.     

Building Algebra Testlets: A Comparison of Hierarchical and Linear Structures

Earlier (Wainer & Lewis, 1990), we reported the initial development of a testlet-based algebra test. In this account, we provide the details of this excursion into the use of testlets. A pretest of two 15–item algebra tests was carried out in which examinees' performance on a 4-item subset of each test (a 4–item testlet) was used to predict performance on the entire test. Two models for constructing the testlets were considered: hierarchical (adaptive) and linear (fixed format). These models are compared with each other. It was found on cross–validation that, although an adaptive testlet is superior to a fixed format testlet, this superiority is modest, whereas the potential cost of that superiority is considerable. It was concluded that in circumstances similar to those we report a fixed format testlet that uses the best items in a pool can do almost as well as the optimal adaptive testlet of equal length from that same pool.     

The effects of instruction on college nonmajors' conceptions of respiration and photosynthesis

Students in a college nonscience majors' biology course took tests designed to reveal their conceptions of respiration and photosynthesis before and after course instruction. Even though most students had taken at least a full year of biology, serious misconceptions persisted. Most students gave definitions of respiration, photosynthesis, and food which were markedly different from those generally accepted by biologists. These incorrect definitions were associated with more fundamental misunderstandings about how plants and animals function. Most students could not explain how animal cells use either food or oxygen. They understood plants as vaguely analogous to animals, taking in food through their roots instead of mouths. Previous biology instruction seemed neither to improve student performance on the pretest nor to prepare them to master these conceptions during the course. Course instruction did improve student's understanding, but misconceptions persisted for many students. These results raise fundamental questions about the effectiveness of curriculum and instruction in current high school and college biology courses.     

Straight Talking: The Nature of Effective Career Discussion at Work

Many employees need help from others in managing their careers, and it is likely that much of this help will be given in the context of a face-to-face discussion, either in a formal setting or more informally. Drawing on the accounts of 104 UK employees who had participated in helpful career discussions, this paper examines with whom and in what settings effective career discussions took place, and the skills and personal qualities displayed by givers and receivers of support. A wide range of individuals provided this form of support. The most important skills and qualities shown by givers of support were: the personal qualities of interest, commitment and trustworthiness; challenging and facilitative skills; giving honest feedback; and providing information.     

The relationship between design reflectivity and conceptions of informed design among high school students

ABSTRACT

Although reflection is a key behaviour of expert designers, it is often a challenging task for new designers. In addition, research on the reflectivity of student designers is limited. The purpose of this study is twofold: (1) to identify the levels of reflectivity while designing, and (2) to study the relationship between reflectivity and conceptions of informed design. We collected data from high school students engaged in an engineering design project. We developed a coding protocol to score levels of reflectivity in student reflections at three levels (low, medium, and high), and used the conceptions of design test to assess changes in student understanding of design activities. Using Wilcoxon signed-rank tests, we determined if students tended to select more ‘key’ design activities and fewer ‘distractors’ within each reflection group. We also performed McNemar’s tests to determine which specific design activities were important within each reflection group after the design project. The results show moderately reflective students had higher gains in understanding of informed design activities compared to those with high or low reflectivity. Results also indicate that different design activities became important for students within each of the three reflective groups. Implications from this research indicate that groups of students experience changing conceptions of design in different ways. An understanding of what students deem important while designing would better allow teachers to encourage behaviours that are like those of informed designers.     

Eliminating behavior with omission and extinction after varying amounts of training

After rats were trained to leverpress for 1, 3, 9, or 27 days on a variable interval reinforcement schedule, omission training was compared with extinction in effectiveness of response elimination. Extinction produced faster response elimination than omission, although both procedures eventually led to equal response elimination. Resistance to response elimination increased with length of baseline training, although this effect did not interact with omission vs extinction. A test of the durability of elimination effects followed, using a response-independent variable time reinforcement schedule. After extinction, resumption of responding in the durability test increased with length of baseline training, but there was little response resumption following omission regardless of the length of the baseline training. These results amplify and extend previous findings which show omission to be an effective and durable response elimination method.     

Transgressing the norm: Transformative agency in community-based learning for sustainability in southern African contexts

Environment and sustainability education processes are often oriented to change and transformation, and frequently involve the emergence of new forms of human activity. However, not much is known about how such change emerges from the learning process, or how it contributes to the development of transformative agency in community contexts. The authors of this article present four cross-case perspectives of expansive learning and transformative agency development in community-based education in southern Africa, studying communities pursuing new activities that are more socially just and sustainable. The four cases of community learning and transformative agency focus on the following activities: (1) sustainable agriculture in Lesotho; (2) seed saving and rainwater harvesting in Zimbabwe; (3) community-based irrigation scheme management in Mozambique; and (4) biodiversity conservation co-management in South Africa. The case studies all draw on cultural-historical activity theory to guide learning and change processes, especially third-generation cultural-historical activity theory (CHAT), which emphasises expansive learning in collectives across interacting activity systems. CHAT researchers, such as the authors of this article, argue that expansive learning can lead to the emergence of transformative agency. The authors extend their transformative agency analysis to probe if and how expansive learning might also facilitate instances of transgressing norms – viewed here as embedded practices which need to be reframed and changed in order for sustainability to emerge.     

GRADING A‐LEVEL DOUBLE SUBJECT MATHEMATICIANS AND THE IMPLICATIONS FOR SELECTION

This study used entry data from the 1980 Summer examination of the University of Cambridge Local Examinations Syndicate to assess the comparative grading of two forms of double mathematics: separate Pure and Applied papers as against Mathematics and Further Mathematics.

The data confirm expectation, and existing evidence, in finding that whilst in the former system the two resulting grades are approximately equal, in the latter case large grade differences abound. These different patterns suggest that there may be some lack of comparability between the two types of award.

Using grades in Physics as a monitor it is shown that if the aggregate is based upon the compensatory model then those entering the separate papers appear to achieve less well (and significantly so at certain levels). On the other hand if the conjunctive model is adopted then the two systems appear to yield very similar results. These findings, if typical of the national picture, have clear implications for those involved with the selection of post‐Alevel students, particularly for further study in mathematics and related subjects.     

Type of high school biology program and its effect on student attitude and achievement in college life science

A specially designed questionnaire and a modification of the “Science Classroom Activity Checklist” by L. H. Krockendorfer were used to categorize 299 life science students at the University of Iowa into two groups; those with high school biology backgrounds founded in the BSCS philosophy and those with traditionally oriented backgrounds. These groups were compared with respect to grade achievement in a college life science course, ratings of their background for the college course, and their attitude toward biology as established by their high school experience. With respect to inquiry and student-centered methods, texts were revealed as poor indicators of types of programs offered.     

The CS-US interval (ISI) function in rabbit nictitating membrane response conditioning with very long intertriai intervals

In Experiment 1, four values of conditioned stimulus-unconditioned stimulus interval, or interstimulus interval (ISI) (200, 500, 800, and 1,100 msec) were studied in one trial/day acquisition of the conditioned nictitating membrane response of the rabbit. The 1,100-msec ISI group was superior to the other groups, contrary to the usual findings of ISI studies in the conditioning literature. In Experiment 2, effective conditioning levels were attained with an ISI as long as 2,200 msec, when the intertriai interval was set at either 24 or 48 h. Results are interpreted in terms of the role of orienting responses in the conditioning process.