Natalie Sullivan1, Matthew Walenski2, Tracy Love3, Lewis P Shapiro3. 1. SDSU/UCSD Joint Doctoral Program in Language and Communicative Disorders, San Diego, CA, USA. 2. School of Speech Language and Hearing Sciences, San Diego State University, San Diego, CA, USA. 3. SDSU/UCSD Joint Doctoral Program in Language and Communicative Disorders, San Diego, CA, USA; School of Speech Language and Hearing Sciences, San Diego State University, San Diego, CA, USA.
Abstract
BACKGROUND: It is well accepted that individuals with agrammatic Broca's aphasia have difficulty comprehending some sentences with filler-gap dependencies. While investigations of these difficulties have been conducted with several different sentence types (e.g., object relatives, Wh-questions), we explore sentences containing unaccusative verbs, which arguably have a single noun phrase (NP) that is base-generated in object position but then is displaced to surface subject position. Unaccusative verbs provide an ideal test case for a particular hypothesis about the comprehension disorder-the Intervener Hypothesis-that posits that the difficulty individuals with agrammatic Broca's aphasia have comprehending sentences containing filler-gap dependencies results from similarity-based interference caused by the presence of an intervening NP between the two elements of a syntactic chain. AIM: To assess a particular account of the comprehension deficit in agrammatic Broca's aphasia-the Intervener Hypothesis. METHODS & PROCEDURES: We used a sentence-picture matching task to determine if listeners with agrammatic Broca's aphasia (LWBA) and age-matched neurologically unimpaired controls (AMC) have difficulty comprehending unaccusative verbs when placed in subject relative and complement phrase (CP) constructions. OUTCOMES & RESULTS: We found above-chance comprehension of both sentence constructions with the AMC participants. In contrast, we found above-chance comprehension of CP sentences containing unaccusative verbs but poor comprehension of subject relative sentences containing unaccusative verbs for the LWBA. CONCLUSIONS: These results provide support for the Intervener Hypothesis, wherein the presence of an intervening NP between two elements of a filler-gap dependency adversely affects sentence comprehension.
BACKGROUND: It is well accepted that individuals with agrammatic Broca's aphasia have difficulty comprehending some sentences with filler-gap dependencies. While investigations of these difficulties have been conducted with several different sentence types (e.g., object relatives, Wh-questions), we explore sentences containing unaccusative verbs, which arguably have a single noun phrase (NP) that is base-generated in object position but then is displaced to surface subject position. Unaccusative verbs provide an ideal test case for a particular hypothesis about the comprehension disorder-the Intervener Hypothesis-that posits that the difficulty individuals with agrammatic Broca's aphasia have comprehending sentences containing filler-gap dependencies results from similarity-based interference caused by the presence of an intervening NP between the two elements of a syntactic chain. AIM: To assess a particular account of the comprehension deficit in agrammatic Broca's aphasia-the Intervener Hypothesis. METHODS & PROCEDURES: We used a sentence-picture matching task to determine if listeners with agrammatic Broca's aphasia (LWBA) and age-matched neurologically unimpaired controls (AMC) have difficulty comprehending unaccusative verbs when placed in subject relative and complement phrase (CP) constructions. OUTCOMES & RESULTS: We found above-chance comprehension of both sentence constructions with the AMCparticipants. In contrast, we found above-chance comprehension of CP sentences containing unaccusative verbs but poor comprehension of subject relative sentences containing unaccusative verbs for the LWBA. CONCLUSIONS: These results provide support for the Intervener Hypothesis, wherein the presence of an intervening NP between two elements of a filler-gap dependency adversely affects sentence comprehension.