PARSING OF SENTENCES IN A LANGUAGE WITH VARYING WORD-ORDER - WORD-BY-WORD VARIATIONS OF PROCESSING DEMANDS ARE REVEALED BY EVENT-RELATED BRAIN POTENTIALS

Event-related brain potentials (ERPs) were recorded while native speak ers read German sentences in which the order of the sentence elements subject, indirect object, and direct object was systematically varied. All sentences were legal grammatical constructions. Sentences were pr esented word by word and a question on the role assignments had to be answered 5 s after the presentation of the final word or each sentence . Behavioral data confirmed previous findings showing that sentences w hose word order deviates from the canonical sequence of subject, indir ect and direct object are more difficult to process. ERPs revealed sev eral effects which differed in their antecedent conditions, topography , and timing: (1) Anticipating a question which taxes episodic verbal knowledge was accompanied by a pronounced tonic negative shift having a left anterior maximum. (2) Article which function as case markers in German evoked a transient, left anterior negativity whenever they ind icated that a noun phase sequence would not continue in its canonical order. (3) Nouns which follow case markers at noncanonical positions w ere accompanied by an enlarged transient posterior positivity. (4) Pro cessing of words at terminal positions in sentences with a noncanonica l word order was accompanied by a sequence of effects: a slow posterio r positivity, a transient anterior negativity, and a transient posteri or negativity, respectively. These effects are discussed in relation t o functionally distinct parsing mechanisms. They show that ERPs may he lp to disentangle functionally distinct processes during language comp rehension even when no behavioral output is generated by the participa nt. (C) 1998 Academic Press.