Comprehension of Anaphoric Pronouns

This study was undertaken to demonstrate that a property of verbs, implicit causality, is an important factor in determining coreference of potentially ambiguous anaphoric pronouns in a timed comprehension task. Subjects were required to decide the coreferentiality of a pronoun in pairs of sentences such as John telephoned Bill because he withheM some information~wanted some information. Verbs were first empirically classified into those that bias assignment toward the first noun phrase of the main clause and those that bias assignment toward the second noun phrase. Pairs of sentences were constructed for each verb such that the subordinate clause in one sentence established a reading consistent with the natural bias of the verb while the others established a reading inconsistent with the bias of the verb. Time to respond was faster for the congruent sentences. This was also true for control sentences such as Sue telephoned Bill because he withheld some information in which gender differences eliminated all potential ambiguities. It was argued from these results that implicit causality is an important determinant of pronoun assignment and that ambiguities arenormal ly resolved at clause boundaries.