1. Subjects with schizophrenia have an impairment very early in visual information processing, requiring a longer minimal stimulus duration than normal controls to identify a target stimulus. Subjects with schizophrenia have a deficit in visual backward masking, identifying fewer target stimuli than normal controls when the target is briefly obscured by a second visual stimulus When interstimulus interval is increased parametrically, subjects with schizophrenia have trouble identifying target stimuli at intervals that do not affect the performance of normal controls. 2. The visual backward masking deficit: is trait-related; is associated with negative symptoms but has also been associated with measures of thought disorder; may or may not be related to treatment with neuroleptic medication or other neurocognitive deficits of schizophrenia; is of unclear etiology, though researchers have speculated that it involves magnocellular channels and/or the cortical dorsal visual processing stream; has been shown to be heritable in one study. 3. If visual information processing deficits are observed in the unaffected siblings of schizophrenic patients, it may be a candidate intermediate phenotype.