There were two points of departure for the work summarized here on the development of children's comprehension of universal quantifiers. One came from the claim that there is a mental logic (Braine 1978; Braine, Reiser, & Rumain 1984). The mental logic theory posits that some logical framework is available essentially innately. The child's task is to learn, through experience, associations between natural-language logical expressions and representations in the mental logic. Much of the theoretical work of Braine and colleagues in this area has been on reasoning at a propositional level with inferences that depend on the meanings of words like and, or, if, and not (e.g. Braine et al. 1984; Braine 1990; Braine, O'Brien, Noveck, et al. 1995). Expanding the work on reasoning to include inferences involving quantifiers has been on the agenda from the start and several years ago we became interested in the issue of the development of comprehension of universal quantifiers such as all, each, and every, in part because they give rise to an especially rich set of inferences.

Our initial framework for thinking about universal quantifiers and their development stemmed from the work of Vendler (1967) and Ioup (1975). Vendler suggested that there were at least two sorts of basic representations corresponding to the meanings of all, each, and every. First was a collective representation whereby a predicate applies to a whole set in a collective sense.