Proceedings of the Annual Meeting of the Cognitive Science Society

We present some ideas about how thematic roles (case roles) associated with verbs are used during on-line language comprehension along with some supporting experimental evidence. The basic idea, following Cottrell (1985), is that all of the thematic roles associated with a verb are activated in parallel when the verb is encountered. In addition, we propose that thematic roles are provisionally assigned to arguments of the verbs as soon as possible, with any thematic roles incompatible with such an assignment becoming inactive. Active thematic roles that are not assigned arguments within the sentence are entered into the discourse model as unspecified entities or addresses. In our first experiment we show that temporary garden-paths arise when subjects initially assign the wrong sense to a verb as in Bill passed the test to his friend, but not when subjects initially assign the wrong role to the noun phrase, as in Bill loaded the car onto the platform. This prediction follows directly from our assumptions. In our second experiment we show that definite noun phrases without explicit antecedents in the preceding discourse can be more readily integrated into a preceding discourse when they can be indexed to an address created by an open thematic role.