This study investigates three-year-olds' representations of the attitude verbs think and know, in attempt to assess children's understanding of factivity. Know is factive and is therefore used in contexts where the complement is taken to be true. Think, although nonfactive, is still often used in situations where the complement is taken to be true. Are children able to recognize the difference between know and think and to understand that the truth of the complement is presupposed in one case but not the other? Acquisition studies on know and think find that children do not have an adult-like understanding of these verbs and their (non-)factivity before the age of four, but these tasks are often inappropriate for testing preschoolers' understanding of factivity for independent reasons. We designed an interactive game to implicitly evaluate children's knowledge of these verbs in a task that more directly targets factivity. Our results show that some three-year-olds are able to distinguish think and know, particularly in ways that suggest they understand that know presupposes the truth of its complement, and that think does not. The remaining threeyear-olds, however, seem to treat both as non-factive. This suggests that early representations of know may be non-factive, and raises the question of how children come to distinguish the verbs.

How do children discover which linguistic expressions are associated with presuppositions? Do they take a direct strategy of tracking whether linguistic expressions are associated with particular speaker presuppositions? This strategy may fail children who are trying to learn about the presuppositions of so-called "soft" presupposition triggers, which can be readily used even when the relevant would-be presupposed content is not part of the common ground. We present a corpus study with the soft trigger know and the related, but non-presuppositional think. We find that a direct learning strategy would indeed run into problems for such a soft trigger given the nature and availability of evidence in children's linguistic input.

How should knowledge be analyzed? Compositionally, as having constituents like belief and justification, or as an atomic concept?In making arguments for or against these perspectives, epistemologists have begun to use experimental evidence from developmental psychology and developmental linguistics. If we were to conclude

No abstract