Brain responses to morphologically complex words: an electrophysiological study on Swedish past tense forms
Andrea Schremm1, Mikael Novén1, Merle Horne1, Mikael Roll1; 1Lund University, Sweden
Dual system models postulate two distinct neural mechanisms for the processing of inflected words: irregular forms (e.g. ‘went’) are assumed to be directly accessed as whole word representations, whereas regularly inflected items (e.g. ‘played’) might undergo rule-based decomposition (Pinker & Ullman, 2002). Irregular verb stems incorrectly carrying a regular inflectional suffix have been reported to elicit a left anterior negativity (LAN), commonly interpreted as indexing violation of morphosyntactic regularities, and thus indicating rule application associated with the regular inflection (e.g. Penke et al., 1997). In the first electrophysiological study on Swedish regular/irregular verb morphology, we recorded brain responses to correct versus incorrect past tense verbs visually presented in sentences. Irregular verb stems incorrectly inflected with the regular suffix generated an increased left-lateralized negativity, interpreted as a LAN for misapplication of the morphological inflection rule. No negativity was observed for regular verb stems incorrectly containing a stem vowel change on analogy to irregular verb patterns. These findings are in line with previous results suggesting that a rule-based processing route is available for regularly inflected items. Alternatively, the observed waveforms might be interpreted in terms of a decreased negativity for correct irregular verbs. Such verbs would then be directly accessed in the lexicon while the other conditions would involve morphological analysis, eliciting increased left-lateralized negativities, including incorrect regular verbs where rule-based processing might have been triggered by regularities in the stem vowel change. From this perspective, LAN might signal morphological rule application instead of detection of rule violation (Krott & Lebib, 2013).
Topic Area: LANGUAGE: Other