Auditory perception in word association performance of schizophrenics and nonschizophrenics

The purpose of the present experiment was to determine whether the cognitive- disorder which results in disturbed verbal communication in schizophrenia is a function of a pathological breakdown in the process of perception of auditory word stimuli or in the process of association. In this study, perception referred to the lower order cognitive process which involves recognition and discrimination of individual words from specially constructed lists presented with two sets of instructions. Association referred to the more complex cognitive process which involves reference of the perceived word to a conceptual category from which a word is selected as a response associate. The procedure involved the presentation of two word lists to 20 pairs of male schizophrenics who were matched with nonschizophrenics for age, intelligence and verbal ability, and educational level. Each subject (S) passed a stringent hearing test to ensure auditory acuity within the normal range. In addition, each S's ability to communicate intelligibly was intact. The lists were presented in a counterbalanced order, the first with instructions to repeat- each word as rapidly as possible. The second list was administered with the usual word association instructions to say the first word which came to mind as rapidly as possible. A reproduction phase followed, also under time pressure. The major hypothesis was that the pathological breakdown in schizophrenia which results in disturbed communication lies in the process of perception rather than in the process of association. The results supported this hypothesis. Schizophrenics misheard significantly more words on the repeat task than nonschizophrenics. In addition, all association response words (RWs) which seemed unrelated to the stimulus word (SW) were scored as Distant (one of nine scoring categories). Words in this category were re-evaluated and rescored as misheard (MH) if they were judged to be good responses to words with different meanings but phonetically similar to the SW. Such words were then assigned to appropriate categories. As a result, it was found that schizophrenics had significantly more MH words than nonschizophrenics. Furthermore, there were no differences between the 20 matched pairs in the number of Distant association RWs. Nor were any differences found between schizophrenics and nonschizophrenics in the frequency of Distant RWs when words which were not misheard or words which were misheard were considered separately. In addition to distant responses, other word association variables which have been used as "diagnostic indicators" were examined. The major finding was that besides misperceived SWs, reaction time is a highly stable variable in differentiating schizophrenics and nonschizophrenics. Also considered were commonality, reproduction failures, and faults.