Analogy Between Sequential Errors in Aphasia and the Behavior of a Cybernetic System (SARF)

A comparison is made between a very f requent type of e r r o r in aphasia ( "Sequent ia l Er ro rs " i n v o l v i n g a pa i r o f i d e n t i c a l l i n g u i s t i c u n i t s , l i k e phonemes or graphemes) and the behav ioura l " f a i l u r e s " of a cybernet ic system: SARF. The s t r u c t u r e of the Sequent ia l Er rors is e x p l i c a t e d , and ru l es fo r desc r i b ing them are given b r i e f l y . The s i m i l a r i t y between these e r r o r s , and the e r ro rs made by an independent ly cons t ruc ted cyberne t ic system, SARF, is shown. The cond i t i ons of a co r rec t comparison between SARF behaviour and the language produc t ion of aphasic people are examined. Hypotheses are i n f e r r e d about the funct i o n a l s t r u c t u r e of b r a i n mechanisms respons ib le f o r both abnormal and normal i n t e g r a t i o n and s e r i a t i o n of asemantic u n i t s in language p roduc t i on ; these hypotheses have led to new e v i dence at other l eve l s of language.