Children take only some sentences literally: investigating children's variable performance with scalar inferences

This thesis investigates young English-speaking children's understanding of several kinds of scalar inferences. For adult speakers, scalar inferences are derived in response to sentences that have been introduced in a conversational context by negating alternative sentences that are more informative, but were not asserted.The findings of previous studies have revealed significant variation in children's sensitivity to scalar inferences. A family of explanations called the Alternatives-based approach attribute children's variable performance in computing scalar inferences to differences in the ease with which they can compose the relevant alternatives. A basic claim of this approach is that children more readily compute scalar inferences when they can assemble the alternatives using elements from the asserted sentence. The experiments reported in this thesis were designed to evaluate this claim by investigating children's performance with a series of untested inferences. The inferences that are tested in the thesis include distributive and conjunctive inferences (Chapter 2), two kinds of free choice inferences (Chapter 3), and two inferences associated with sentences where 'some' is in the scope of 'every' (Chapter4). The results of these investigations support the Alternatives-based approach by demonstrating that children readily compute inferences in which the alternatives can be formulated using parts of the asserted sentence. The results also provide contributions to several other important theoretical issues.