Preattentive information processing as measured by backward masking and texton detection tasks in adolescents at high...

Schizophrenic patients have consistently been reported to show deficits in preattentive information processing as demonstrated by impairments in visual backward masking and texton detection tasks. Texton detection refers to Julesz's texton theory, which defines a certain limited number of texton elements (e.g., one 'L' among many '+') that can be detected readily and simultaneously without attentional effort irrespective of the size of the rest of the visual field. The present study investigated whether deficits of preattentive information processing are more prevalent in a group of adolescents of high genetic risk for schizophrenia compared to matched control subjects. Although differences in the performance in visual backward masking tasks could not be detected with our experimental approach, preattentive texton detection was to a certain extent disturbed in subjects at risk. Moreover, subjects at risk did not show the advantage of the right hemisphere in processing texton elements which was found in the control group. This may point to a subtle dysfunction of the right hemisphere in the risk group. It is concluded from the present study that deficits in preattentive texton detection may represent an indicator for a schizophrenic disposition. However, further studies including other high risk groups, schizophrenics in remission and individuals with a schizotypal personality disorder are needed to confirm this hypothesis.