Frequency and predictability effects on event-related potentials during reading.
Effects of frequency, predictability, and position of words on event-related potentials were assessed during word-by-word sentence reading in 48 subjects in an early and in a late time window corresponding to P200 and N400. Repeated measures multiple regression analyses revealed a P200 effect in the high-frequency range; also the P200 was larger on words at the beginning and end of sentences than on words in the middle of sentences (i.e., a quadratic effect of word position). Predictability strongly affected the N400 component; the effect was stronger for low than for high-frequency words. The P200 frequency effect indicates that high-frequency words are lexically accessed very fast, independent of context information. Effects on the N400 suggest that predictability strongly moderates the late access especially of low-frequency words. Thus, contextual facilitation on the N400 appears to reflect both lexical and post-lexical stages of word recognition, questioning a strict classification into lexical and post-lexical processes.
Helmholtz Center for the Study of Mind and Brain Dynamics, Department of Psychology, University of Potsdam, P.O. Box 60 15 53, 14451 Potsdam, Germany. dambach@uni-postdam.de
Michael
M
Dambacher
Reinhold
R
Kliegl
Markus
M
Hofmann
Arthur M
AM
Jacobs
D000328:Adult; D000704:Analysis of Variance; D004569:Electroencephalography / Q000379:methods; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D010775:Photic Stimulation; D011237:Predictive Value of Tests; D011930:Reaction Time / Q000502:physiology; D011932:Reading; D012044:Regression Analysis; D014706:Verbal Learning / Q000502:physiology