Syntactic transparency and sentence interpretation in aphasia

Abstract

Abstract A semantic anomaly judgement test was used to test the hypothesis that sentence comprehension errors by agrammatic aphasics arise as a consequence of faulty mapping from syntactic functions to thematic roles. In one condition, anomalies arose out of a thematic role reversal which was carried by the syntactic structure (e.g., # The worm swallowed the bird). Mis-mapping in these cases would have the effect of altering plausibility and hence resulting in erroneous judgments. In a second condition, mismapping was of no consequence (e.g., # The cat divorced the milk). Effects of sentence length (“Padding”) and of the transparency with which thematic roles are syntactically encoded (“Moved-arguments”) were examined across both types of anomaly. Overall, the performance pattern of agrammatics reveals considerable sensitivity to syntactic structure per se. Their difficulty seems to lie in the utilization of syntactic information for the assignment of thematic roles, particularly where the syntactic relationship between the verb and its noun arguments is not transparently evident in surface structure.