Processing arguments and adjuncts in isolation and context: The case of by-phrase ambiguities in passives

Two eye-tracking experiments examined processing of sentences like The shrubs were planted by the apprentice/greenhouse that morning, where the by phrase is locally ambiguous between an agent and a location. Experiment 1 found a preference to initially interpret the by phrase agentively in the absence of context. In Experiment 2, a context like The head gardener decided [who should]/[where to] plant the shrubs induced an expectation that either an agent or a location would subsequently be specified. After agentive contexts, locatives were harder to process than agentives. After locative contexts, both sentences were easy to process. The authors argue that the verb and interrogative words (who, where) activate thematic roles, which can be associated with corresponding phrases. Phrases that express activated roles are easy to process. Phrases that might express activated roles but are subsequently shown not to express those roles require reanalysis.