Some aspects of the visual search and scanning behaviour of schizophrenics

Same measures of scanning and search behaviour are explored, and their relation to the postulated attention deficit of schizophrenics is investigated. The tasks used required Ss to scan multielement displays and to either respond to a predefined target, or to make a same-different decision. The primary experimental manipulations involved varying stimulus complexity, defined both in terms of numbers of elements, and stimulus structure. The results suggested that scanning rates do not differ between controls and schizophrenics, over a range of stimulus complexity, although there is a significant tendency for the patients (especially the older, long term Ss) to have a constant, slower RT. This implies that slow schizophrenic RT may be more largely determined by response organization and execution, rather than stimulus input processing. These results are discussed in the context of methodological problems, research on the attention processes of non psychiatric Ss, and current notions of cognitive functioning advanced by the schizophrenic deficit theorists