To test the Lewis and Mayer simulation model (1987) for understanding compare problems, 3 experiments involving 39 college students and 15 third graders used registration of eye movements. Two experiments somewhat support the model, suggesting it holds true only when the task puts cognitive demands on the subject. (SLD)

Results of a study involving 107 sixth graders, 107 secondary school students, and 99 college education majors support the basic hypothesis of the intuitive model of solving multiplicative problems proposed by E. Fischbein and others (1985) but show that the theory does not account for all the empirical data. (SLD)