ABSTRACT
The importance of cognitive dysfunction in schizophrenia, highlighted by Kraepelin and Bleuler at the turn of the century, was largely ignored until the late 1950s, when the study of animal and human cognition began to flourish. This new line of research by experimental psychopathologists was marked by the publication of a book called Perception and Communication (Broadbent, 1958). Using work relating to vigilance, selective listening and shifting attention, Broadbent postulated a central control mechanism for filtering out irrelevant information. It was later proposed that a defective ‘filtering’ mechanism may underlie the psychological dysfunction in schizophrenia. McGhie and Chapman (1961) also concluded that the primary deficit in schizophrenia was in the control and direction of attention. This broad conclusion was accepted with general consensus amongst schizophrenia researchers in the 1960s. Since then, experimental cognitive paradigms have been used to identify specifically impaired cognitive processes in schizophrenia, and theories have emerged which aim not only to provide a unifying cognitive framework, but also to link them to symptoms (e.g. Hemsley, 1977, 1993; Frith, 1979; Frith and Done, 1988; Frith, 1992).
