Sustained meaning activation for polysemous but not homonymous words: Evidence from EEG

Abstract

Theoretical linguistic accounts of lexical ambiguity distinguish between homonymy, where words that share a lexical form have unrelated meanings, and polysemy, where the meanings are related. The present study explored the psychological reality of this theoretical assumption by asking whether there is evidence that homonyms and polysemes are represented and processed differently in the brain. We investigated the time-course of meaning activation of different types of ambiguous words using EEG. Homonyms and polysemes were each further subdivided into two: unbalanced homonyms (e.g., "coach") and balanced homonyms (e.g., "match"); metaphorical polysemes (e.g., "mouth") and metonymic polysemes (e.g., "rabbit"). These four types of ambiguous words were presented as primes in a visual single-word priming delayed lexical decision task employing a long ISI (750 ms).Targets were related to one of the meanings of the primes, or were unrelated. ERPs formed relative to the target onset indicated that the theoretical distinction between homonymy and polysemy was reflected in the N400 brain response. For targets following homonymous primes (both unbalanced and balanced), no effects survived at this long ISI indicating that both meanings of the prime had already decayed. On the other hand, for polysemous primes (both metaphorical and metonymic), activation was observed for both dominant and subordinate senses. The observed processing differences between homonymy and polysemy provide evidence in support of differential neuro-cognitive representations for the two types of ambiguity. We argue that the polysemous senses act collaboratively to strengthen the representation, facilitating maintenance, while the competitive nature of homonymous meanings leads to decay.

Polysemy and word meaning: an account of lexical meaning for different kinds of content words

“…According to Frisson (2009Frisson ( , 2015, Klepousniotou et al (2012), MacGregor et al (2015), and others, in polysemy resolution we do not see a strong bias for the most frequent, or dominant, sense. Indeed, senses prime each other no matter which sense is more frequent, and their common activation survives for at least 750 ms (MacGregor et al, 2015).…”

“…According to Frisson (2009Frisson ( , 2015, Klepousniotou et al (2012), MacGregor et al (2015), and others, in polysemy resolution we do not see a strong bias for the most frequent, or dominant, sense. Indeed, senses prime each other no matter which sense is more frequent, and their common activation survives for at least 750 ms (MacGregor et al, 2015). These observations, together with the further observation that words with multiple senses are recognized faster (in lexical decision tasks) than words with less senses and, especially, than homonyms (Azuma and van Orden, 1997), suggests that the representation and storage of polysemous senses is very different from the representation and storage of homonym meanings (see also similar results concerning production reported in Li and Slevc, 2016).…”

“…For instance, MacGregor et al (2015) tested the polysemy of mouth as in mouth of a person, mouth of a river and mouth of a cave, and observed the same overall pattern of co-priming and facilitation effects observed in regular polysemy. While there are some differences between the two cases (regular vs metaphor-based polysemies) with respect to the speed of response in a lexical decision task (Keplousniotou and Baun, 2007), and, in general, in the time it takes for one sense to activate another (MacGregor et al, 2015), both cases seem to pattern together when the contrast class is homonymy. In particular, within 750 ms after prime offset, an incoherent meaning of a homonymous word has decayed, whereas an incoherent sense of a polysemous word is still activated.…”

“…In particular, within 750 ms after prime offset, an incoherent meaning of a homonymous word has decayed, whereas an incoherent sense of a polysemous word is still activated. MacGregor et al (2015;138) therefore conclude that, also in the case of metaphor-based polysemies, "sustained activation of both meanings of polysemous words supports an account of representation in which the multiple senses are stored together" and that "the different senses act collaboratively to strengthen the representation, which facilitates the maintenance even after a long delay".…”

“…show that different metaphorical chains relate to different aspects of the metonymically generated meaning of mouth. (MacGregor et al, 2015). The question is whether (BIG)MOUTH and MOUTH (OF A RIVER) would also prime each other.…”