Attentional and information processing dysfunctions have long been considered to be core deficits of schizophrenia (Bleuler, 1911/1950; Kraepelin, 1919). According to this view, many of the characteristic symptoms of schizophrenia are consequences of underlying attentional and information processing dysfunctions. Despite the apparent consensus concerning the importance of these dysfunctions, close examination of the literature reveals considerable disagreement about their specific nature. Some investigators have suggested that schizophrenic patients suffer from primary deficits in controlled attentional processes (e.g., Callaway & Naghdi, 1982; Gjerde, 1983; Nuechterlein & Dawson, 1984b). Others have hypothesized primary deficits in the automatic, preattentive stages of information processing (e.g., Braff & Geyer, 1990; Frith, 1979; Venables, 1984). The possibility that primary deficits in automatic processing might lead to dysfunctions in controlled processing in some situations has also been considered (e.g., Nuechterlein & Dawson, 1984b).

The distinction between automatic and controlled cognitive processes has been prominent in cognitive psychology since the 1970s (Posner & Snyder, 1975; Shiffren & Schneider, 1977). Although there is not perfect agreement about all characteristics that distinguish automatic and controlled processes, there is nevertheless fundamental agreement about the key distinctions (Schneider, Dumais, & Shiffrin, 1984). Automatic cognitive processes occur rapidly, in parallel, demand little or no conscious attention and effort, and are difficult if not impossible to suppress voluntarily. Controlled cognitive processes, in contrast, occur slowly, in series, demand allocation of attentional resources and effort, and are under voluntary control. Most cognitive psychologists agree that automatic and controlled processes may occur in rapid sequence following presentation of salient stimuli.