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1994 Book DidacticsOfMathematicsAsAScien
trial by ordeal: In the tutoring study, teachers' ideas for improvement were
"field tested" in a tutoring session with a real student and the ideas either did or did not enhance learning. In the problem-design study, suggested problems measured up to a set of guiding principles or failed to do so (Lesh et al., 1993). In the assessment design study, proposed scoring rubrics measured up to a set of guiding principles or failed to do so; (c) trial by jury: In each of the three studies, each group of teachers compared and contrasted their suggestions against those in consensus-forming discussions. In these discussions, arguments were forwarded for which suggestions to keep, which to weed out, how they should be organized and prioritized, and how they might form a coherent conceptual system. Overall, the driving force in selection appeared to be the result of the resolution of various cognitive conflicts: task-interpretation mismatches, interpretation-representation mismatches, environment-model mismatches, model-tool mismatches, specific-general mismatches, and procedure-logic mismatches. 2.5 Adaptation As a positive consequence of mutation, demands from the environment (challenges to proposed models) cause problem solvers, collectively and RICHARD LESH AND ANTHONY E. KELLY 279 ACTION THEORY AND PHENOMENOLOGY individually, to modify or extend existing ideas in one or more of the fol- lowing ways: reorganization, coordination, differentiation, and integration. Reorganization. We wanted to provide experiences that would encourage teachers and students to switch to some completely new ways to think about their suggestions. Sometimes these reorganizations occurred when cognitive conflicts were presented. We noted some of the pertinent mismatches above. Other reorganizations occurred when "wild ideas" (e.g., metaphors and analogies drawn from brainstorming sessions) were considered that sug- gested a reinterpretation of a direction or approach. Coordination, or the "building up" process. Over time, teachers and stu- dents gradually constructed more flexible and stable conceptual systems for interpreting their suggestions. Sometimes we encouraged alternating be- tween situations in which attention was focused on the constituent parts of complex acts, other times on situations in which the focus was on the flexi- bility and coordination of the systems-as-a-whole. To help teachers gradually coordinate and refine their tutoring systems- as-a-whole, we gradually increased the complexity of the contexts in which the learner was to perform – while preserving the basic structure of the task. For example, the complexity of tutoring sessions increased naturally as teachers gradually noticed new types of relevant factors ranging from math- ematical issues, to psychological issues, to pedagogical issues; and, tutoring activities also became more complex as we introduced ways to use graphics (other computer-based tools) as parts of hints, feedbacks, or follow-up questions. In the problem-design and assessment-design projects, we raised concerns such as how well a given problem statement would draw upon the students' experiences, or how well it documented students' work. Alternatively, we asked if a scoring rubric that appeared satisfactory for teachers was of equal value for parents or for the students themselves. Differentiation: The "splitting" process. Conceptual systems do not sim- ply get "built up" (or constructed) in a bottom-up manner; models also get "sorted out." Teachers and students discriminate among alternative models: those they have constructed and those that they have been given. The differ- entiation process sometimes means that students and teachers temporarily lose sight of the "large picture" when they pay attention to details of a model. Alternatively, when the focus is on a single model, they lose sight of others. We have found it to be a useful intervention with teachers and stu- dents to redirect their attention to larger issues or components of their mod- els or alternative models that they are neglecting. 2.6 Accumulation When models are developing, the problem solver does not start from scratch each time. The parts of the models that have served well in the past are re- tained and become part of a larger and more comprehensive solution. The 280 accumulating model draws upon representations and notation systems that were helpful in the past. The emerging model helps guide the teacher in tu- toring decisions, in designing tasks, and evaluating responses; it helps guide students in applying articulated models to new problem situations. Arising out of the design of action-theoretic studies of emerging expertise among students and teachers, we have noted the following: In the tutoring study, teachers moved progressively away from rule-oriented mathematics and toward model-centered mathematics. Their interventions were reduced in number and changed in character. They became less concerned, for ex- ample, with procedural errors, and more interested in students' thinking: Were students using more than one representational system? Were the models they were constructing equal to the tasks that were set? In the problem-design study, teachers moved away from designing prob- lems that had a single correct answer (for which students' thinking and rea- soning processes were not documented) toward ones in which the central goal of the task was to promote model building and model documentation. In the response-evaluation study, teachers moved away from assigning holistic scores that covered many types of responses toward assessment pro- cedures that considered the conditions of testing, student-related factors, task-related factors, and their curricular goals in mathematics. They then considered how to produce rich descriptions of the students' work. Finally, considering both the conditions and descriptions, they evaluated the stu- dents' work. 3. CONSEQUENCES OF CONSTRUCTIVISM FOR A RESEARCH METHODOLOGY When researchers adopt a constructivist orientation toward thinking and learning, they must adapt their research methodology accordingly. Given the assumptions of constructivism, can researchers predict with confidence the state or level of construction of a concept that a student will reveal? If not, attempts to prescribe what constitutes an "expert" state, and what con- stitutes a "novice" state are open to question. As a corollary, pre- and posttests that reify these a priori codifications of expertise are also open to question. Further, research and teaching agendas whose goal is to bridge this hypothesized "gap" with prescriptions may be misguided. Detailed observations of children's thinking make clear that students' thinking is often inadequately described by either the novice or expert prescriptions of researchers (e.g., Carpenter, Fennema, & Romberg, 1993; Maher, Davis, & Alston, 1991). Some children's thinking is haphazard, showing some "expert" characteristics and some "novice" characteristics. The thinking of other children frequently goes beyond the expectations of "expertise" that were assumed for them (Lesh, Post, & Behr, 1989). Further, since children's thinking evolves in complex ways over pro- tracted periods of time, the a priori timing of a prescribed instrument to be RICHARD LESH AND ANTHONY E. KELLY 281 used as a "posttest" may be quite arbitrary and may or may not succeed in recording the changes in learning that it was designed to record. If children construct ideas complexly over a long period of time, then researchers must be willing to make continuous, rich, longitudinal observations of children. Researchers must also focus on authentic tasks. Researchers in mathemat- ics education should be primarily concerned about students' construction of real mathematics, not about drawing remote inferences about mathematical problem-solving based on scores from indices such as multiple-choice as- sessments of procedural knowledge. We should be concerned with mathe- matical problem-solving, not with surrogates of this process. Finally, the constructivist approach suggests that researchers should pay Download 5.72 Mb. Do'stlaringiz bilan baham: |
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