Stella Vosniadou

Mental Models of the Earth: A Study of Conceptual Change in Childhood.

This paper presents the results of an experiment which investigated elementary school childrens conceptual knowledge about the earth. First-, 3rd-, and 5th- grade children were asked a series of questions about the shape of the earth. Childrens responses to these questions revealed considerable apparent inconsistency. For example, many children said that the earth is round but also stated that it has an end or edge from which people could fall. A great deal of this apparent inconsistency could be explained by assuming that the children used, in a consistent fashion, a mental model of the earth other than the spherical earth model. Five alternative mental models of the earth were identified: the rectangular earth, the disc earth, the dual earth, the hollow sphere, and the flattened sphere. It is argued that these models are constrained by certain presuppositions which children form based on interpretations of their everyday experience. Some of these models (the rectangular earth and the disc earth) seem to be initial models children construct before they are exposed to the culturally accepted information that the earth is a sphere. In the process of knowledge acquisition, children appear to modify their initial models to make them more consistent with the culturally accepted model by gradually reinterpreting their presuppositions. Synthetic models (such as the hollow sphere and the flattened sphere) are generated by children as a solution to the problems arising from the inconsistency between their initial model of a flat earth and the culturally accepted, scientific model of a spherical earth. Children come to understand that the earth is a sphere only when the presuppositions that gave rise to their initial models have been reinterpreted.

Theories of Knowledge Restructuring in Development

This paper reviews recent work on knowledge acquisition with a focus on knowledge restructuring. This work suggests that it may be possible to replace Piagetian theories of global restructuring with a more domain-specific approach. Some forms of learning may give rise to a weak restructuring involving the accumulation of new facts and the formation of new relations between existing concepts. Other forms of learning may involve a radical restructuring that includes a change in core concepts, a change in structure, and a change in the phenomena to be explained. The restructuring view raises important questions about the similarities and differences in the child’s and the scientist’s acquisition of knowledge, and about the role of prior knowledge in instruction. The domain of observational astronomy is used as an example of how these issues can be applied to study the child’s development of knowledge. Several mechanisms for knowledge restructuring are discussed and it is argued that these issues are crucial for a theory-based approach to the study of instruction.

Designing learning environments to promote conceptual change in science

Abstract It is argued that research on the acquisition of science concepts has rich implications for the teaching of science and can lead to the development of useful principles for the design of learning environments. An experimental project that attempted to use these research-based principles to construct a learning environment for teaching mechanics to fifth- and sixth-grade students is described. The students were encouraged to take active control of their learning, express and support their ideas, make predictions and hypotheses and test them by conducting experiments. They worked in small groups and presented their work to the classroom for debate. Metaconceptual awareness was promoted by encouraging students to make their ideas overt, to test them and compare them with those of other students and to give scientific explanations. Emphasis was also placed on giving the students the opportunity to use models, representational symbols, and measurements. Results showed significant differences between the experimental and control groups in pre-test–post-test comparisons, confirming our hypothesis that the experimental learning environment would result in cognitive gains for the participating students. Further interview analyses and analyses of the classroom discourse helped to clarify some of the variables contributing to the observed conceptual change.

From conceptual development to science education: a psychological point of view

A theoretical framework based on cognitive/developmental research is described. It is argued that science learning is a gradual process during which initial conceptual structures based on childrens interpretations of everyday experience are continuously enriched and restructured. Conceptual change also involves increased metaconceptual awareness, cognitive flexibility, and theoretical coherence. Some of the implications of this research for the development of science curricula and for instruction are discussed. It is also argued that while cognitive/developmental research can provide us with important information about the process of learning science, it does not provide much information about the external, environmental variables that can facilitate cognitive performance and conceptual change. What is needed in the future is the development of a theory of learning that bridges science education and cognitive/developmental research. Such a theory should specify the mechanisms that can take an individual ...

On the Nature of Naïve Physics

The argument will be advanced in this paper that naive physics is neither a collection of unstructured knowledge elements nor a collection of stable misconceptions that need to be replaced,but rather a complex conceptual system that organises children’s perceptual experiences and information they receive from the culture into coherent explanatory frameworks that make it possible for them to function in the physical world.The processof learning science appears to be a slow and gradual one during which aspects of the scientific information are added on to the initial explanatory framework destroying its coherence until (and if)itis restructured in ways to make it consistent withcurrently accepted scientific views.

Mental Models of the Earth, Sun, and Moon: Indian Children's Cosmologies.

Abstract This study reports data on the acquisition of knowledge about astronomy in children from India. Based on prior research, we hypothesized that the cosmological models that children construct are influenced by both first-order and second-order constraints on knowledge acquisition. First-order constraints are the implicit assumptions that govern the construction of initial cosmological models. Examples of such constraints include the assumptions that the earth is flat and supported. Such first-order constraints are presumed to be universal. Second-order constraints arise from the specific properties ascribed to cosmological objects. For example, representations of the earths shape and location relative to the sun and moon constrain the kinds of mechanisms that are generated to account for the day-night cycle. We hypothesized that in cultures where both folk cosmologies and the scientific cosmological model are accessible to children, aspects of folk models are likely to be incorporated in childrens cosmologies if they provide a psychologically easier way of satisfying first-order constraints. This hypothesis is supported by our findings with regard to universality and culture specificity in childrens cosmologies. Indian childrens cosmologies honor a variety of universal first-order constraints. These include constraints on the shape of the earth (e.g., support and flatness) and on the relative locations and motions of objects in the cosmology (e.g., continuity). However, many Indian children borrow the idea that the earth is supported by an ocean or a body of water from folk cosmology. This solution to the support constraint on the shape of the earth is not found in American childrens initial cosmologies.

Children and metaphors

VOSNIADOU, STELLA. Children and Metaphors. CHILD DEVELOPMENT, 1987, 58, 870-885. Recent research on the development of childrens abilities to comprehend and produce metaphorical language is reviewed. It is argued that the ability to produce and comprehend metaphorical language emerges out of childrens undifferentiated similarity notions and develops gradually to encompass a greater variety of conceptual domains. Although we do not yet have adequate theories of how metaphor comprehension or production develop, there is good reason to believe that this is a continuous rather than a stagelike process, and that it is constrained primarily by limitations in childrens knowledge and information-processing abilities. Furthermore, it appears that the comprehension and production of metaphorical language involve transfer of knowledge from one conceptual domain to another which, on the one hand, depends critically on the conceptual knowledge the child already has, and on the other acts to enrich and advance this conceptual knowledge.

Conceptual Change and Education

In order to understand the advanced, scientific concepts of the various disciplines, students cannot rely on the simple memorization of facts. They must learn how to restructure their naive, intuitive theories based on everyday experience and lay culture. In other words, they must undergo profound conceptual change. This type of conceptual change cannot be achieved without systematic instruction that takes into consideration both individual, constructivist and sociocultural factors. Teachers must find ways to enhance individual students’ motivation by creating a social classroom environment that supports the creation of intentional learners who can engage in the deep and enduring comprehension activities required for the revision of conceptual knowledge.

Mental Models in Conceptual Development

Models are important in science because they can be used as instruments to help in the construction of theories. They are the sources of both predictive and explanatory power and can be used to suggest new hypotheses and aid in scientific discovery. In this paper I argue that the mental models that children construct also have predictive and explanatory power and can be used as mediating mechanisms for the revision of existing theories and the construction of new ones.

How Many Decimals Are There Between Two Fractions? Aspects of Secondary School Students’ Understanding of Rational Numbers and Their Notation

We present an empirical study that investigated seventh-, ninth-, and eleventh-grade students’ understanding of the infinity of numbers in an interval. The participants (n = 549) were asked how many (i.e., a finite or infinite number of numbers) and what type of numbers (i.e., decimals, fractions, or any type) lie between two rational numbers. The results showed that the idea of discreteness (i.e., that fractions and decimals had “successors” like natural numbers) was robust in all age groups; that students tended to believe that the intermediate numbers must be of the same type as the interval endpoints (i.e., only decimals between decimals and fractions between fractions); and that the type of interval endpoints (natural numbers, decimals, or fractions) influenced students’ judgments of the number of intermediate numbers in those intervals. We interpret these findings within the framework theory approach to conceptual change.