Selective attention and response competition in schizophrenic patients.

Visual distractibility was studied in schizophrenic patients. Subjects had to respond to target stimuli while they ignored the visual context, which was either congruent, neutral, or incongruent with respect to the target stimulus. Eighteen schizophrenic patients and 18 healthy subjects performed this flanker task. Schizophrenic patients did not show increased distractibility compared with healthy subjects, and both groups showed the same attenuation of visual context effects when the spatial distance between target and flanker stimuli was increased. The two groups showed the same amount of interference by incongruent visual context. Thus, schizophrenic patients did not show enhanced distractibility, spatial extension of attention, or response competition. When flanker and target stimuli were redundant, the responses of schizophrenic patients were less accelerated than those of healthy subjects.