Graded Brain Responses to Regular and Irregular Inflection 1 Running Head: GRADED BRAIN RESPONSES TO REGULAR AND IRREGULAR INFLECTION Continuous Processing of Linguistic Categories: Behavioral and Electrophysiological Responses to Regular and Irregular Verb Inflection in German

This study examined whether German regular and irregular verb inflection is processed in continuous or categorical ways. Two visual priming experiments contrasted regular (regular stem, regular suffix) with two types of irregular participle formation (regular/irregular stem, irregular suffix). We measured reaction times (RT; Experiment 1) and event-related potentials (ERPs; Experiment 2) and manipulated both the inflectional relation and the meaning relation between primes and targets. Inflected verb targets (e.g., stöhne, ‘moan’) were preceded by themselves, by their participle (gestöhnt, ‘moaned’), by a semantically related verb in the same inflection (seufze, ‘sigh’) or in the participle form (geseufzt, ‘sighed’), and by an unrelated verb in the same inflection (blinke, ‘blink’) or in the participle form (geblinkt, ‘blinked’). The behavioral results showed no distinction between regular and irregular verbs as such, but rather a complex interaction of the factors frequency, meaning, and inflectional relation between primes and targets. The electrophysiological data showed that verb regularity gradually affected priming: regular participles produced a widely distributed frontal and parietal effect, irregular participles a small left parietal effect, with semi-irregular participles in between. The data thus provide evidence that the linguistic categories of verb inflection are not processed categorically but gradually. We present a single-system model that can adequately account for such graded effects.