Psychological verbs and the double-dependency hypothesis

The double-dependency hypothesis (DDH, Mauner et al.,1993) holds that where two dependencies of a certain kind are present, comprehension in Broca's a phasia will be random, but that where there is only one dependency, compreh ension will be intact. We tested this hypothesis by examining the performan ce of Broca's aphasics on sentences with psychological verbs of two differe nt classes. One class has an argument structure in which the Experiencer ro le is assigned to the subject. In the other class, the Experiencer role is assigned to the object. Subject-Esperiencer verbs can form verbal passives which have two relevant dependencies, whereas object-Experiencer verbs can form adjectival passives and have only one relevant dependency. Thus these sentence types make contrasting predictions relevant to the DDH. Our result s clearly demonstrate that patients understand the adjectival passive psych ological verbs, as predicted by the DDH. On the verbal passive psychologica l verbs, patients perform at chance, again consistent with DDH predictions. These results firmly buttress the DDH account. They also contradict the re sults of an earlier study (of verbal passive psychological verbs only), a s tudy which we argue is plagued with problems (namely, Grodzinsky, 1995b). ( C) 2001 Academic Press.