Cognitive Penetrability of Syntactic Priming in Broca's Aphasia

Agrammatic Broca's aphasia has been explained as an impairment of automatic syntactic processes. The present study investigated whether controlled processes play a role in agrammatics' handling of syntactic information. Agrammatic patients and normal controls performed a cross-modal priming task with sentence fragments and visual targets forming either grammatical or ungrammatical pairs. In Experiment 1, subjects of both groups were instructed to ignore the auditory prime. The grammaticality effect observed in a previous study disappeared for the aphasic subjects but not for normal controls. Experiment 2 demonstrated that for normal controls the grammaticality effect was present even with a larger prime-target interval. These findings indicate that although automatic parsing routines in normal subjects are impervious to strategic effects, agrammatic Broca patients appear to use syntactic information in a controlled fashion.