Developmental evidence against the theoretical distinction between Horn and pragmatic scales

A theoretical distinction between Horn and pragmatic scales that are instrumental in generating scalar implicatures (SIs) is widely accepted in neo-Gricean pragmatics; at the same time, this distinction has been questioned in some neo-Gricean and post-Gricean accounts of SIs. In order to explore whether or not this distinction has a reflex on the way in which children acquire SIs, I tested 40 children (4;3-7;7) on computing SIs based on Horn and pragmatic scales. If this distinction is postulated, children are predicted to perform better on computing SIs based on Horn scales. In my experiment, children did significantly better on computing SIs based on pragmatic scales. Moreover, children performed worse on certain Horn scales than on the pragmatic scales, and better on other Horn scales than on the pragmatic scales.I provide theoretical reasons against distinguishing between Horn and pragmatic scales, and propose my own Context-based QUD account of SIs on which children's performance on computing SIs is a function of challenges presented by individual scales. I identify three major linguistic and cognitive acquisitional challenges presented by scales, and how these predict the timeline of SI acquisition.

► I tested experimentally a theoretical distinction between Horn and pragmatic scales.
► My acquisitional results on scalar implicatures do not support this distinction.
► I provide novel theoretical reasons against postulating the distinction in question.
► I propose a question-under-discussion account of scalar implicatures.
► I discuss in detail the acquisitional challenges presented by a variety of scales.