Verb transitivity bias affects on-line sentence reading in people with aphasia

Background: Studies of sentence comprehension in non-disordered populations have convincingly demonstrated that probabilistic cues influence on-line syntactic processing. One well-studied cue is verb argument structure bias, which refers to the probability that a verb will occur in a particular syntactic frame. According to the Lexical Bias Hypothesis people with aphasia have difficulty understanding sentences in which the verb's argument structure bias conflicts with the sentence structure (e.g., a transitively biased verb in an intransitive sentence). This hypothesis may provide an account of why people with aphasia have difficulty understanding both simple and complex sentences.Aims: The purpose of this study was to test the Lexical Bias Hypothesis using an on-line measure of written sentence comprehension, self-paced reading. Methods & Procedures: The participants were 10 people with aphasia and 10 non-brain-damaged controls. The stimuli were syntactically simple transitive and intransitive sentences that contained transitively or intransitively biased verbs. For example, the transitively biased verb "called" appeared in sentences such as "The agent called (the writer) from overseas to make an offer." The intransitively biased verb "danced" appeared in sentences such as "The couple danced (the tango) every Friday night last summer."Outcomes & Results: Both groups' reading times for critical segments were longer when the verb's transitivity bias did not match the sentence structure, particularly in intransitive sentences.Conclusions: The results were generally consistent with the Lexical Bias Hypothesis, and demonstrated that lexical biases affect on-line processing of syntactically simple sentences in people with aphasia and controls.