After more than thirty years of research since Hunt and Cofer's (1944) classic review, investigators have no clear understanding of the nature and significance of schizophrenic thought disorder. Countless investigations have probed facets of the problem, and numerous reviewers (Broen, 1968; Buss & Lang, 1965; Chapman & Chapman, 1973; Lang & Buss, 1965; Maher, 1966; Payne, 1961; Salzinger, 1973) have assessed the many hypothetical constructs purported to describe or explain schizophrenic thinking. Although many promising explanations have been offered, no single one seems to characterize schizophrenic thought. Is it a loss of abstraction (Goldstein, 1944; Wright, 1975), overinclusion of concepts into categories (Cameron, 1947; Chapman & Taylor: 1957), accentuated response bias (Chapman & Chapman, 1973), lawful disorganization by collapse of response hierarchies (Broen, 1966, 1968), immediacy of stimuli (Salzinger, 1973), or autism (Shimkunas, Gynther, & Smith, 1967)? This question is not new and has been posed a number of times, both implicitly and explicitly (Buss & Lang, 1965; Chapman & Chapman, 1973; Salzinger, 1973).