ERP and behavioral effects of semantic ambiguity in a lexical decision task Juan Haro * , Josep Demestre, Roger Boada, Pilar Ferr  e Research Center for Behavior Assessment (CRAMC), Department of Psychology, Universitat Rovira i Virgili, Tarragona, Spain article info Article history: Received 7 November 2016 Received in revised form 25 May 2017 Accepted 21 June 2017 Keywords: Semantic ambiguity Ambiguity advantage Meanings relatedness Polysemy Homonymy Word recognition ERP N400 abstract In the present study we examined electrophysiological and behavioral correlates of ambiguous word processing. In a lexical decision task, participants were presented with ambiguous words with unrelated meanings (i.e., homonyms; e.g., bat), ambiguous words with related meanings (i.e., polysemes; e.g., newspaper), and unambiguous words (e.g., guitar). Ambiguous words elicited larger N400 amplitudes than unambiguous words and showed an advantage in RTs. Importantly, no differences were found between homonyms and polysemes, on either N400 amplitudes or in RTs. These results suggest that ambiguous words, regardless of the relatedness between their meanings, benefit from enhanced se- mantic activation in comparison to unambiguous words during word recognition. © 2017 Elsevier Ltd. All rights reserved. 1. Introduction Understanding how meaning is retrieved from printed words and how it is represented in the mind are two primary goals of word recognition research. A fruitful line of research has been devoted to elucidate how orthography and semantics interact during word recognition, and to examine which semantic variables play a role in this process. Among such variables, semantic ambiguity has been one of the most studied. Semantic ambiguity refers to a linguistic phenomenon in which an orthographic form is mapped to more than one meaning (e.g., the word pupil, which means both a student and the opening in the iris of the eye). Given this one-to-many relation between orthography and meaning, semantic ambiguity poses intriguing questions for word recognition research. One central issue is whether ambiguous words have one or multiple lexical/semantic representations. For instance, are both meanings of the word pupil (e.g., student and part of the eye) included in the same lexical/semantic representation, or are they listed in separate lexical/semantic representations? A further crucial question is how orthography and semantics interact during the recognition of ambiguous words. Do the meanings student and part of the eye compete during the recognition of the word pupil? Or rather, does having two meanings, and thus more semantic in- formation, facilitate the recognition of such a word? The aim of the present study was to shed some light on these questions by examining the behavioral and electrophysiological correlates of ambiguous word processing. * Corresponding author. Research Center for Behavior Assessment (CRAMC), Department of Psychology, Universitat Rovira i Virgili, Crta. de Valls s/n, Campus Sescelades, 43007, Tarragona, Spain. E-mail address: juan.haro@urv.cat (J. Haro). Contents lists available at ScienceDirect Journal of Neurolinguistics journal homepage: www.elsevier.com/locate/jneuroling http://dx.doi.org/10.1016/j.jneuroling.2017.06.001 0911-6044/© 2017 Elsevier Ltd. All rights reserved. Journal of Neurolinguistics 44 (2017) 190e202