Effects of verb bias and syntactic ambiguity on reading in people with aphasia

Abstract

Background: The Lexical Bias Hypothesis claims that people with aphasia (PWA) have difficulty understanding sentences when the verb’s argument structure bias conflicts with the sentence structure. This hypothesis can account for comprehension deficits that affect simple sentences, but the role of verb bias has not been clearly demonstrated in temporarily ambiguous sentences.

Aims: This study examined how verb bias affects comprehension of temporarily ambiguous and unambiguous sentences using self-paced reading.

Methods & Procedures: PWA and controls read sentences that contained sentential complements (e.g., The talented photographer accepted (that) the fire could not have been prevented). The main verb was biased to take a direct object (e.g., accepted) or a sentential complement (e.g., admitted). In addition, the sentential complement was either introduced by the complementiser that (i.e., unambiguous) or unmarked (i.e., ambiguous).

Results: The reading times of PWA were affected more by verb bias than by the presence of the complementiser, whereas the control group’s reading times were more affected by the presence or absence of the complementiser.

Conclusions: The results were generally consistent with the Lexical Bias Hypothesis, and showed that a mismatch between verb bias and sentence structure affected the processing of unambiguous and temporarily ambiguous sentences in PWA.

Keywords:

• Reading comprehension
• Temporary syntactic ambiguity
• Aphasia
• Lexical Bias Hypothesis

This work was supported in part by an American Speech Hearing Foundation New Investigators Grant and NIDCD [grant number DC010808]. The author thanks the research participants and their families and the students who helped with the data collection. The author would also like to thank Audrey Holland and Janet Nicol for helpful comments on a previous draft of this manuscript.

Notes

2. ¹ Note that this study focuses on syntactic parsing, which plays a critical role in building a mental representation of the sentence and determining who did what to whom. In contrast, the grammar can be considered a description of which structures are grammatical or ungrammatical within a language. To the extent that the grammar is viewed as psychologically real, the parser may use grammatical knowledge as one of the possible sources of information in making parsing decisions.

3. ² These participants were also reported in DeDe (2013).

4. ³ Another set of analyses was run to control for the plausibility of the noun as a direct object for the main verb. This was accomplished by including the plausibility ratings in the regression analyses. The pattern of significance for the PWA and controls was identical to the results reported here.