The simon effect in schizophrenic patients with negative symptoms

Automatic shifting of visual attention was investigated using the Simon task in schizophrenic patients with prevailing negative symptomatology. Reaction times were recorded in condition of spatial correspondence and non-correspondence between side of spatially defined responses and side of stimulus presentation. Schizophrenic patients showed asymmetries between the two hemifields attributable to a slowing down of reaction times for non-corresponding trials in the left hemifield. These results are interpreted as a deficit in the process that inhibits the automatic corresponding response, and in general as a difficulty to inhibit dependence on external stimuli, in the left hemifield/right hemisphere.