Levels of Linguistic Representation in Broca's Aphasia: Implicitness and Referentiality of Arguments1

We investigated the interaction between different levels of linguistic representation and the syntactic deficit in Broca’s aphasia. We varied a semantic property of arguments referentiality, and a phonetic property implicitness, and crossed them with the constructions that expose the syntactic deficit in agrammatic Broca’s aphasia. Our results show that referentiality and implicitness of arguments interact with θ-role assignment in agrammatic comprehension of passive constructions. Using a truth value judgment paradigm, differential performance was documented: we observed above chance performance in the comprehension of passives with quantified subjects; and at chance performance on short passives (without a by-phrase), in conjunction with the standard finding of above-chance performance on actives, and at-chance on agentive passives. We conclude that (1) knowledge of information on referentiality is not only accessible to the agrammatic patients, but also interacts with their deficit in a surprising manner; (2) information about implicit arguments (semantically existent, yet phonetically unrealized elements) is represented for them; (3) these new findings lend further support to the Trace-Based Account (TBA) the recent reformulation of the Trace-Deletion Hypothesis.