Effects of right- and left-hemisphere damage on understanding conversational implicatures

Asa Kasher, Gila Batori, Nachum Soroker, David Graves, Eran Zaidel*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

52 Scopus citations


Processing of implicatures was examined in 27 right-brain-damaged (RBD) and 31 left-brain-damaged (LBD) stroke patients with focal lesions using a new implicatures battery (IB) as part of an exploration of the neural basis and modularity of natural language pragmatics. Following Grice, we sampled implicatures of Quantity, Quality, Relation, and Manner. Verbal implicatures consisted of two-sentence conversational vignettes which are literally problematic. Nonverbal implicatures consisted mostly of famous paintings that are literally problematic (e.g., Magritte's 'Le Domain d'Arnheim'). The patient has to identify and solve the problem. To compare with performance on the IB, patients also received a Hebrew adaptation of Gardner and Brownell's Right Hemisphere Communication Battery, a new test of basic speech acts (verbal and nonverbal assertions, questions, requests, and commands), a Hebrew version of the Western Aphasia Battery, and standardized neuropsychological tests. Both LBD and RBD patients were significantly impaired in implicature processing relative to age-matched normal controls. In general, both patient groups showed weak correlations of implicatures with extents of lesions in left perisylvian language area or its right-hemisphere (RH) homolog. However, performance of LBD and RBD patients on the IB revealed different patterns of correlations with other pragmatic, language, and nonlanguage tests. In LBD patients, there was a greater association between performance on verbal and nonverbal implicatures and between performance on implicatures and basic speech acts than in RBD patients. Given the different modes in which right-and left-hemisphere (LH) damage affect the processing of conversational implicatures, it remains to be discovered how the two hemispheres interact to process natural language pragmatics in the normal brain in real time.

Original languageEnglish
Pages (from-to)566-590
Number of pages25
JournalBrain and Language
Issue number3
StatePublished - Jul 1999


FundersFunder number
Basic Research Foundation of the Israel National Academy of Science
U.S.–Israel Binational Science Foundation77392
National Institute of Neurological Disorders and StrokeR01NS020187


    • Conversational implicatures
    • Gricean maxims
    • Inferences
    • Language pragmatics
    • Localization of function
    • Right hemisphere
    • Unilateral brain damage


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