Research in Science Education, 1990, 20, 181 - 190
THE CONSTRUCTIVIST PARADOX: TEACHERS' KNOWLEDGE AND CONSTRUCTIVIST SCIENCE TEACHING
William Louden Western Australian Ministry of Education
and John Wallace
Curtin University of Technology
Advocates of constructivist science recommend that school science begins with children's own constructions of reality. This notion of the way in which students' knowledge of science grows is closely paralleled by recent research on teachers' knowledge. This paper draws on case study evidence of teachers' work to show how two experienced teachers' attempts to develop alternative ways of teaching science involved refraining their previous patterns of understanding and practice. Two alternative interpretations of the case study evidence are offered. One interpretation, which focuses on identifying gaps in the teachers' knowledge of science teaching, leads to the constructivist oaradox. The second interpretation explores the constructivist parallel, an approach which treats the process of teachers' knowledge growth with the same respect as constructivists treat students' learning of science. This approach, the authors argue, is not only more epistemologicaUy consistent but also opens up the possibilities of helping teachers lead students towards a constructivist school science.
Constructivist science is emerging as the new orthodoxy in science education. For some, constructivist science may seem to be one more program o! change, the next in a long line that began with the curriculum reforms of the 1960s and includes Project Physics, Chem Study, Web of Life, Nuffield, ASEP and the science, technology and society movement. For others, constructivist science is a fundamental point of departure, requiring science educators to accept a new epistemology of science (von Glasersfeld, 1987; Clemlnson, 1990; Tobin, Kahle & Fraser, 1990).
Constructivist science builds on the observation that scientific knowledge is constructed by men and women. Whereas positivists might see knowledge of the universe as a giant jigsaw pu771e, and the task of scientists as finding the lost pieces, constructivists allow the possibility that there are many different jigsaw patterns by which we can represent our knowledge of the universe. Working together, scientists share their jigsaws, agree which gaps are worthy of inquiry, and what counts as compelling evidence that they have found a missing piece.
There is widespread intellectual support for these ideas. Post-positivist philosophers in general (e.g. Schutz, 1973; Ricoeur, 1974; Gadamer, 1975; Foucault, 1976) and philosophers of science in particular (e.g. Polanyi 1962; Lakatos, 1970; Popper, 1972; Feyerabend, 1975) have argued that knowledge is constructed wilh;n communities of
like-minded people, rather than discovered and guaranteed by the certainty of an objective experimental method. The practice of science is not the linear, rational process which scientists often presume, nor which is described in school science text books (GarIinkel et at., 1981; Knorr-Centina, 1982; Matthews, 1990). What we call scientific knowledge is no more than intersubjective agreement among a group of scientists. Such agreements about scientific reality depend on the paradigm within which they are constructed, and tend to live and die with particular groups of scientists working within a paradigm (Kuhn, 1970). At the extreme, the idea that all knowledge is socially constructed has been taken to mean that science has no greater authority than astrology, animism or mysticism. The more moderate view argued here is that "science can acquire valid and useful knowledge that is nevertheless a product of human thought, subject to change in the light of new evidence and reasoning" (Brush, 1989, p. 64).
In parallel with these ideas, science educators have argued that traditional school science, with its positivist assumptions about knowledge, should be replaced by a new construetivist approach. Building on the psychological theories of Piaget (1929), Kelly (1955) and Vygotsky (1962), construcfivists have proposed that school science should begin with children's own constructions of reality (Osborne & Wittrock, 1985; Pines & West, 1986). Teachers should encourage students to make their own ideas explicit, present students with events which challenge these ideas, encourage the generation of alternative interpretive models and provide opportunities for students to use new ideas in a range of situations (Driver & Bell, 1986). In short, science teachers should resist "the scientific preference for imposing truths on the world, rather than just letting the world speak in its own messy way" (Matthews, 1990, p. 12).
For many teachers, reared on positivist assumptions about science, the idea that scientific knowledge is a matter of intersubjective agreement among scientists rather than transcendental and permanent truths discovered about the universe is very disturbing. A constructivist notion of science also conflicts with the predominant, content-centred, chalk, talk and lab. book pedagogy of science teaching. More than this, it conflicts with the ideas about science which have dominated teachers' own academic training and the ideas about science which have dominated popular thought for many years. As Gunstone and Northfield (Notes 1 & 2) have pointed out, constructivist school science requires fundamental changes in many teachers' concepts of teaching and learning.
Prompted by this gap between what teachers know and what constructivists encourage them to do, this paper brings together some ideas about science with some ideas about teachers' knowledge, and attempts to open up for discussion some parallels and paradoxes.
Like scientific knowledge, theoretical accounts of teachers' understanding of their work are constructed wilhin communities of like-minded people. Two such constructions of the nature of teachers' knowledge are in terms of hofizon~ and im_m_gtg~. These metaphors have been used by the authors as the basis for understanding the nature of teachers' work in two separate studies of teaching (Louden, in press; Wallace, 1989).
The first view is a that teachers' knowledge is framed by horizons of understandin~ (Louden, in press). Viewed from this perspective, teaching is a struggle to discover and maintain a settled practice, a set of routines and patterns of action which resolve the problems posed by particular subjects and groups of children. These patterns, content and resolutions to familiar classroom problems, are shaped by each teacher's biography and professional experience. The meaning of these patterns of action only becomes clear when it is set in the context of a teacher's personal and professional history, hopes and dreams for teaching, and working environment. A teacher's response to new problems is shaped by these historically sedimented predispositions to action which form a horizon of understanding. Such horizons are not static, but are constantly in the process of formation. Confronted by new problems and challenges, a teacher struggles to resolve them in ways that are congigtent with the understanding he or she brings to the problem at hand. This process, in turn, leads to the construction of new horizons of understanding about teaching.
Another view of teachers' knowledge is in terms of ~ (Clandinin, 1985; Wallace, 1989). An image of teaching is a kind of knowledge, embodied in the person and connected to the individual's past and present. It reaches into the past, gathering up experiential threads meaningfully connected to the present. Image is like a glue that melds together a person's diverse experiences, both personal and professional. Because no two persons have the same experience, an image is individual and unique. Images connect the teacher with content and pedagogy, providing an explanation for the saying, "You are what you teach." The power of these images is that they serve to summarise or encapsulate teachers' predispositions to action, and consequently shape the direction and possibility of teachers' growth and change.
These two constructions are part of a family of thinking about teachers' knowledge, a family within which there is substantial intersubiective agreement about the nature of the knowledge teachers have and use (Elbaz, 1983; Clandinin 1985; Hunt, 1987; Butt & Raymond, 1987; Connelly & Clandinin~ 1988). The construction which such people share emphasises that teachers' knowledge is tacit, biographical and experiential.
The epistemological parallels between post-positivist science and these notions of teachers' knowledge are striking. The history and philosophy of science suggests that the process of science is not as linear and rational as has been proposed in accounts of the scientific method, and that what counts as scientific truth depends on constructions of reality shared among groups of scientists. Similarly, constructivist science uses children's own constructions of reality as the essential starting point for scientific learning. Research on teachers' knowledge shares the conclusion that knowledge is socially constructed. Furthermore, this research directs attention to the personal and experiential base of teachers' knowledge and the role of previous patterns of practice in shaping the growth of knowledge. The next section of thi~ paper tells two stories about learning to teach science in order to further explore these epistemological parallels.
MAKING MEANING OF SCIENCE
The stories which follow have been chosen to illustrate the process of learning followed by teachers as they deal with new situations. They form part of two longer studies of
teachers and their work carried out by the authors in Canadian elementary schools (Louden, in press; Wallace, 1989).
Bill: The English Teacher v
The first story in this section concerns a teacher and a researcher working together. As part of the collaborative auid pro quo, the researcher -- one of the authors of this paper -- offered to take the Grade 7 and 8 science lessons which had been allocated to the teacher. Neither the teacher, Johann a, nor the researcher had taught science before, although they were both experienced teachers. Little outside help was available, so the researcher, Bill, decided that the best option was to follow a detailed set of lesson notes provided by the school board.
Following these notes, Bill taught a series of conventional lessons on a familiar topic of school science: "Solutions and Mixturds". Although Johann a was grateful that Bill was relieving her of the unwanted burden of teaching science, she could not believe that what the students were being taught would be useful to them and she pressured him into changing his approach. As a compromise, Bill set an assignment on a different syllabus topic and employed a method of teaching which suited Johamaa's preference for self-paced activities based on topics of interest to students. In the lessons that followed the teachers were off centre-stage, there was plenty of time for one-to-one discussions with students, those who were interested in the topic made some progress on the assignment, and the teachers' meagre knowledge of what and how to teach science was not tested.
However, as the date for the completion of the assignment drew closer, Bill became increasingly nervous that the students had not been directly taught the skills of the scientific method which were essential to successful completion of the asxi~ament. His response was to use some of the remaining time to return to teaching the content and skills required to complete the assignment.
For the next session, Bill decided to conduct a lesson on writing up an experiment, again using the school board topic on solutions and mixtures. As the Grade 8 class began filing into the room, it occurred to Bill that the experiment could be done in the format of a television game show, a format he had practised as a teacher of English. He reminded the class that one of the questions in their science ag~ignment asked them to conduct an experiment, and explained that Johanna and he had thought that they might like some help in planning and describing their experiments. In the lesson which followed, Bill employed the game show format to teach his science lesson. By setting up experiments on stools in the centre of the room and using student assistants to conduct the experiments while acting as game show hostesses, Bill was able to teach a lesson and entertain the class. The lesson turned out to be full of animation and enthusiasm. The "hostesses" played up to the audience and responded well to Bill's instructions and suggestions. The audience followed every bit of the theatre in the centre of the room and made notes as Bill dictated them.
Bill finished the lesson by carefully describing the observations he was looking for, soliciting comments from the two student assistants about their own observations. Finally, he dictated a brief conclusion on the characteristics of a solution. The class ended with a brief round of applause for Bill's assistants. As one of the assistants was returning to his desk he said, "That's the closest I've ever been to Pat Sajak" (Note 3).
Despite this vote of approval and Bill's enjoyment in teaching the lesson, he judged it to be a limited success. The goal and content were science, but the pedagogy was clearly English.
Malcolm: The Craft Teacher The second story concerns the involvement of Malcolm, an experienced Grade 4/5 elementary teacher, in a school board sponsored program designed to increase the amount of science taught in elementary schools and to promote an active, cooperative approach to teaching science. This approach promoted a problem-solving orientation to science where students could select problems and design solutions in a socially cooperative setting. Students were to be encouraged to be creative and to explore and share non-standard solutions to science-related problems with their classmates.
The program was well funded and well supported by the school board. Along with other staff members, Malcolm attended a series of central inservice sessions where curriculum materials and teaching strategies were introduced. Collegial support groups were established in Malcolm's school, and the participating teachers were supported by visits from the science consultant. In Malcolm's school, the teachers were given school time to discuss pedagogical issues with their peers and to observe other classes in action.
Malcolm's standard practice was to divide the teaching day into two halves. The first half of the day was spent doing mathematics and English. For this activity, Malcolm taught in manner which was familiar to him. Usually Malcolm would formally present material at the commencement of a lesson and then check students' understanding by aski...