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D R Pharr

Publications and source records attributed to D R Pharr.

3 recordsLinked to original sources
PubMed1980

Memory scanning in a visual search task by schizophrenics and normals.

Chronic schizophrenics, acute schizophrenics (N = 18), and normals (N = 9) participated in a memory scanning task in which the visual display consisted of either common words, word-like strings of letters, or randomly arranged letters. Unlike earlier results, the slope of the function that relates reaction time to memory set size was significantly higher for the two schizophrenic groups than for the normal group. Among the chronic schizophrenics only reaction time to word display was higher than to display with random letters. The implications for theories that hypothesize deficits at specific stages of processing among schizophrenics are discussed.

Adult↗
PubMed1977

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.

Adult↗