Abstract: | In this article, we present SYNCHRON, a computer model of Kolk and van Grunsven's (1985) hypothesis of agrammatic comprehension deficits. According to this hypothesis, parsing fails in agrammatic aphasies since syntactic representational elements that need to be active simultaneously are often not coactive because of disturbances in timing due to brain damage. SYNCHRON has been especially designed to account for two neglected aspects of agrammatic comprehension: degrees of severity and the sentence-complexity effect. We report an attempt to simulate data from two sentence-picture-matching studies in which a qualitatively similar sentence-complexity effect was found at two different average levels of severity. This pattern was reproduced when the timing disorder was assumed to affect syntactic phrasal categories, but not when it was assumed to affect function-word categories. When phrasal categories were involved, fit was not much affected, whether the damage was assumed to slow down the time for an element to be retrieved, or to decrease the time for an element to remain available. |