Understanding Minds and Understanding Communicated Meanings in Schizophrenia

The work reported in this paper investigated the putative functional dependence of pragmatic language skills on general mind-reading capacity by testing theory-of-mind abilities and understanding of non-literal speech in patients with schizophrenia and in healthy controls. Patients showed difficulties with inferring mental states on a false-belief picture-sequencing task and with understanding metaphors and irony on a story-comprehension task. These difficulties were independent of low verbal IQ and a more generalised problem inhibiting prepotent information. Understanding of metaphors and understanding of irony made significant and independent contributions to discriminating patients from controls, suggesting that metaphor and irony make distinct pragmatic demands. Cognitive neuropsychology is that branch of cognitive psychology that investigates people with acquired or developmental disorders of cognition. The aim is to learn more about how cognitive systems normally operate or about how they are normally acquired by studying selective patterns of cognitive breakdown after brain damage or selective difficulties in acquiring particular cognitive abilities. In the early days of modern cognitive neuropsychology, research focused on rather basic cognitive abilities such as speech comprehension or production at the single-word level, reading and spelling, object and face recognition, and short-term memory. More recently the cognitive-neuropsychological approach has been applied to the study of rather more complex domains of cognition such as belief fixation (e.g. Coltheart and Davies, 2000; Langdon and Coltheart, 2000) and pragmatic aspects of communication (e.g. McDonald and Van Sommers, 1993). Our paper concerns the investigation of pragmatic disorders in one clinical group in which such disorders are common, patients with schizophrenia, and what the study of such people can tell us about the normal processes of communication. We would like to thank the organisers of, and the participants in, the Mind & Language Millennial Workshop on Pragmatics and Cognitive Science held at Corpus Christi College, Oxford, in September 2000. Discussions and advice during that Workshop proved invaluable in formulating the focus and direction of the present paper. We are also grateful to two referees for Mind & Language. Address for correspondence: Robyn Langdon, Macquarie Centre for Cognitive Science, Macquarie University, Sydney, NSW 2109, Australia. E-mail: robyn maccs.mq.edu.au Mind & Language, Vol. 17 Nos 1 and 2 February/April 2002, pp. 68–104.  Blackwell Publishers Ltd. 2002, 108 Cowley Road, Oxford, OX4 1JF, UK and 350 Main Street, Malden, MA 02148, USA. Understanding Minds and Communicated Meanings in Schizophrenia 69