Similarities and differences in encoding processes in chronic schizophrenics and normals.

The encoding of visual stimuli was compared for 9 female chronic nonparanoid schizophrenics and 9 normals using the Sternberg paradigm. This paradigm allows an examination of several hypothetical stages in information processing using a reaction time measurement. Degradation level (degraded vs nondegraded), type faces of letter stimuli (varied versus constant type face), and order of degradation levels (mixed or constant level across a block of trials) were manipulated in order to examine differences in encoding process between the two groups. Results suggest two subprocesses in encoding, only one of which is defient in schizophrenics. Additional processing of encoded information at a memory stage may be comparable in normal schiziphrenics. Chronic schizophrenics are also more easily disrupted by the context of varying stimulus conditions such as mixing degradation levels and type faces. This finding suggests schizophrenic perseveration in encoding processes.