The developmental relation between cognitive stage and the comprehension of speaker uncertainty.
3 hypotheses were tested concerning the developmental relation between children's concepts of physical uncertainty and their comprehension of a speaker's uncertainty. 2 cognitive tasks of physical uncertainty were used to assign 56 subjects (aged 5-4 to 17-11) to 1 of 3 cognitive stages. 2 tests for comprehension of speaker uncertainty were administered to all participants. The results indicated that cognitive stage was related to (a) comprehension that a speaker could be uncertain, (b) comprehension that uncertainty could be expressed in different degrees or magnitudes, and (c) the internal consistency of judgments made about the relative degree of uncertainty conveyed by an utterance. These findings are interpreted as evidence for the position that development of cognitive stages is structurally related to comprehension of speech act uncertainty.