Four Levels of Scientific Modeling Practices in Expert Learning

Clement, John

Abstract This paper describes model construction practices used by scientifically trained experts. Our work on science experts has involved analyzing data from videotaped protocols of experts thinking aloud about unfamiliar explanation problems. These studies document the value of nonformal heuristic reasoning processes such as analogies, identification of new variables, Gedanken experiments, and the construction and running of visualizable explanatory models. Although theses processes are less formal than formal deduction or induction or statistical inference procedures, the case study analyzed here shows that they can lead to real insights and conceptual change. At a larger time scale, the subject went through model evolution cycles of model generation, evaluation, and modification that utilized the heuristic reasoning processes above. In addition, the prevalence of imagistic simulation as an underlying foundation in these episodes suggests that it may be important to pay greater attention to an imagistic level of processing in the analysis of expert thinking. Larger time scale modes of model evolution and model competition were also evidenced. The analysis leads to four levels of processes or practices: IV. An overarching set of Model Construction Modes, primarily alternating between Model Evolution, in which a model is improved, and Model Competition, in which two or more models compete. III. Modeling (GEM) Cycle process of Model Generation, Evaluation, and Modification at a Macro level, as shown in Figure 10. II. Nonformal Reasoning Processes at a Micro level: e.g. analogy, running a model, identifying a new variable, and conducting a Gedanken experiment. I. Underlying Imagistic process including Imagistic Simulation that may have been occurring within all of the above processes. To our knowledge these four levels of processes have not been analyzed together in the past. They complement empirical processes of discovery, experimentation, and evaluative argumentation documented by others. Diagrams of how the above processes interact may give us some new ways to picture the roles of nonformal reasoning and imagistic processes during qualitative model construction. We call the set of processes at all four levels a 'Modeling Practices Framework'. Processes at a lower level serve as subprocesses for the level above it in this framework. Each level has multiple "things to try" to achieve tasks at the level above it. Thus the framework is an organized but flexible structure of heuristic processes. This lies between and contrasts with those who would describe theory making in science as either 'anarchistic', with no method structure, or 'algorithmic', with fairly standardized procedures.

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