Canonicity Effect on Sentence Processing of Persian-speaking Broca’s Patients

Fundamental notions of mapping hypothesis and canonicity were scrutinized in Persian-speaking aphasics. 

To this end, the performance of four age-, education-, and gender matched Persian-speaking Broca's patients and eight matched healthy controls in diverse complex structures were compared via the conduction of two tasks of syntactic comprehension and grammaticality judgment.

The tested structures included subject agentive, agentive passive, object experience, subject experience, subject cleft, and object cleft constructions. Our results, while corroborating the predictions of the mapping hypothesis, showed that in structures, in which linguistic elements were substituted and dislocated out of their canonical syntactic positions, namely, agentive passive, subject experiencer, object experiencer, and object cleft constructions, Broca’s problems escalated. In contrast, in those structures whose constituent concatenations were aligned with canonical syntactic structures, namely subject agentive, and cleft structures, patients had above the chance performance. Ultimately, the theoretical and clinical implications of the study were discussed. 

The number of predicates in a sentence, predicate types (psychological and agentive), as well as semantic heuristics and canonicity all by all could be regarded as the major culprits for aphasics' poor performance.