What's in a Model? Issues in the Use of Simulation Models to Analyze Student Understanding: A Reaction to Ohlsson, Ernst, and Rees

Abstract

Ohlsson. Ernst, and Rees (this issue) have produced a wonderfully lucid description of their paradigmatic approach to issues of cognition and instruction. They illustrate their approach by presenting the details of a well worked out computational model. Then, on the basis of simulation runs on the model, they derive some implications for prac tice. The authors have also laid down some rather stringent constraints for commentary. Do not critique our paradigms, they say, unless you can offer a replacement that does better. Do not critique the choice of knowledge representation (production systems) or modeling assumptions (e.g., limitations on working memory) unless you have compelling data to offer in service of your argument and in contradiction of our assumptions. Argument about details is useful, they say, but that won't change the conclusions we draw. So what's a reviewer to do?