Intervention effects in the relative clauses of agrammatics: The role of gender and case

Abstract

Individuals with agrammatic aphasia are known to have difficulties interpreting Object Relative Clauses (ORCs), but not Subject Relative Clauses (SRCs). This asymmetry is recently understood by resorting to locality principles, captured by a featural version of Relativized Minimality (RM). The same principles are held responsible for intervention effects of phi-features with the same value in child language, when these are syntactically active. There are no studies on the intervention effects of phi-features in agrammatism.  This work investigates comprehension of headed Relative Clauses (RCs) by Greek-speaking non-fluent Broca’s aphasics (agrammatics), focusing on gender and structural case, which the language marks on both the determiner and the noun. Two RC tasks were administered, differing on whether the case of the first (relativized) DP was nominative or accusative, depending on the preceding instruction. The findings established the expected SRC vs. ORC asymmetry, shedding light to earlier misleading results due to side effects of case morphology. Moreover, a strong similarity effect of gender was found in ORCs, although it is not a syntactically active feature in the relevant sense in Greek. We claim that the similarity effects of gender in the ORCs of Greek-speaking agrammatics are not intervention effects anchored to some specific principle of syntactic locality. Support for this claim is also provided by their presence even in the SRCs of the same individuals.  As for structural case, neither intervention nor general similarity effects of it were detected. There were, however, additional difficulties for SRCs whose relativized subject had accusative, not patterned by ORCs with nominative relativized objects. We suggest that one has to ensure that relativized subjects end up with nominative case in the RCs tasks of languages with rich case morphology, and conjecture that phi-features are not involved in the computation of locality in agrammatism.