Understanding how input matters: verb learning and the footprint of universal grammar.

Studies under the heading "syntactic bootstrapping" have demonstrated that syntax guides young children's interpretations during verb learning. We evaluate two hypotheses concerning the origins of syntactic bootstrapping effects. The "universalist" view, holding that syntactic bootstrapping falls out from universal properties of the syntax-semantics mapping, is shown to be superior to the "emergentist" view, which holds that argument structure patterns emerge from a process of categorization and generalization over the input. These theories diverge in their predictions about a language in which syntactic structure is not the most reliable cue to a certain meaning. In Kannada, causative morphology is a better predictor of causative meaning than transitivity is. Hence, the emergentist view predicts that Kannada-speaking children will associate causative morphology (in favor of transitive syntax) with causative meaning. The universalist theory, however, predicts the opposite pattern. Using an act-out task, we found that 3-year-old native speakers of Kannada associate argument number and not morphological form with causativity, supporting the universalist approach.