Words in the brain: lexical determinants of word-induced brain activity

Abstract

Many studies have shown that open- and closed-class words elicit different patterns of brain activity, as manifested in the scalp-recorded event-related potential (ERP). One hypothesis is that these ERP differences reflect the different linguistic functions of the two vocabularies. We tested this hypothesis against the possibility that the word-class effects are attributable to quantitative differences in word length. We recorded ERPs from 13 scalp sites while participants read a short essay. Some participants made sentence-acceptability judgments at the end of each sentence, whereas others read for comprehension without an additional task. ERPs were averaged as a function of word class (open versus closed), grammatical category (articles, nouns, verbs, etc.), and word length. Although the two word classes did elicit distinct ERPs, all of these differences were highly correlated with word length. We conclude that ERP differences between open- and closed-class words are primarily due to quantitative differences in word length rather than to qualitative differences in linguistic function.