Using instruments to understand argument structure: Evidence for gradient representation

The arguments of a verb are commonly assumed to correspond to the event participants specified by the verb. That is, drink has two arguments because drink specifies two participants: someone who drinks and something that gets drunk. This correspondence does not appear to hold, however, in the case of instrumental participants, e.g. John drank the soda with a straw. Verbs such as slice and write have been argued to specify an instrumental participant, even though instruments do not pattern like arguments given other criteria. In this paper, we investigated how instrumental verbs are represented, testing the hypothesis that verbs such as slice encode three participants in the same way that dative verbs such as lend encode three participants. In two experiments English-speakers reported their judgments about the number of participants specified by a verb, e.g., that drink specifies two participants. These judgments indicate that slice does not encode three distinct arguments. Nonetheless, some verbs were systematically more likely to elicit the judgment that the instrument is specified by the verb, a pattern that held across individual subjects. To account for these findings, we propose that instruments are not independent verbal arguments but are represented in a gradient away: an instrument may be a more or less salient part of the force exerted by an agent. These results inform our understanding of the relationship between argument structure and event representation, raising questions concerning the role of arguments in language processing and learning.