GOLDSTEIN1 POSTULATED the existence of a deficit in abstracting ability with resultant concrete thinking as a function of the schizophrenic thought process. Benjamin2 introduced the systematic use of proverbs to assess this deficit, stating that "literal answers . . . are common among schizophrenics, even highly intelligent ones" (p 74), but rare for nonpsychotic individuals of dull normal or better intelligence. Proverbs have since often been included in the routine mental status examination.
Interest in proverbs led to the development of more precise methods of evaluating their interpretation.3,4 Research with quantitative procedures disclosed a high positive correlation between IQ and ability to abstract proverbs for normals and schizophrenics3,5 in contrast with Benjamin's earlier finding that literal answers are "much more common in intelligent schizophrenics than in mildly defective nonschizophrenics."* One of the more popular measures is the Gorham Proverbs Test,4 possibly because Gorham has developed equivalent forms,
ALGIMANTAS M. SHIMKUNAS, MALCOLM D. GYNTHER, KATHLEEN SMITH. Abstracting Ability of Schizophrenics Before and During Phenothiazine Therapy. Arch Gen Psychiatry. 1966;14(1):79–83. doi:10.1001/archpsyc.1966.01730070081010