ABSTRACT
The results of Experiments I and II give some evidence that the competence and performance models of Chapters 5 and 6 are at least partly accurate descriptions of the mental processes underlying the comprehension of formulas with the logical form given in (15) (Ch. 2, section 1). Experiment II was designed to assess the generality of the theory along a logical gradient. The experiment tested its ability to predict the relative difficulty of 14 new formulas. The generality of the theory along a semantic gradient has already been tested by the consistency analyses, among others, for Experiments I and II. The theory is indifferent to the four kinds of tasks into which the formulas were interpreted. The consistency analyses of Chapters 3 and 9 show that the children were also largely indifferent to the topic and idiom of a task but seemed rather to focus more on its abstract structure. Since the difference in idioms amounts to the difference between the logic of propositions and the logic of classes, there is thus evidence for some similarity in the mental processes mediating reasoning in these two realms. Our theory seems to be describing at one level these common mental processes.
