“…The factors which have been related to differences between verbal and performance I.Q. 's include such diverse ones as language disability, educational limitations, mixed cerebral dominance, concrete or abstract approaches to tasks, temporary emotional upset, delinquency, neurotic trends, gross behavior disorder, and organic deterioration (3,9,34,55,84). This large array of variables is discouraging in that it provides no simple explanation for the discrepancy between verbal and performance scores in a particular case.…”