INDUCING AGRAMMATIC PROFILES IN NORMALS - EVIDENCE FOR THE SELECTIVE VULNERABILITY OF MORPHOLOGY UNDER COGNITIVE RESOURCE LIMITATION

The selective vulnerability of morphology in agrammatic aphasia is oft en interpreted as evidence that closed-class items reside in a particu lar part of the brain (i.e., Broca's area); thus, damage to a part of the language processor maps onto behavior in a transparent fashion. We propose that the selective vulnerability of grammatical morphemes in receptive processing may be the result of decrements in overall proces sing capacity, and not the result of a selective lesion. We demonstrat e agrammatic profiles in healthy adults who have their processing capa city diminished by engaging in a secondary task during testing. Our re sults suggest that this selective profile does not necessarily indicat e the existence of a distinct subsystem specialized for the implicated aspects of syntax, but rather may be due to the vulnerability of thes e forms in the face of global resource diminution, at least in grammat icality judgment.