Semantic Distance Modulates the N400 Event-Related Potential in Verbal Analogical Reasoning

Computational accounts have traditionally focused on mapping between structured representations as fundamental to analogical processing. However, a recent connectionist model has been used to argue that structured representations may not be necessary to solve verbal analogies. Green and colleagues (2010) have shown that brain areas associated with analogical mapping become more engaged as semantic distance increases between verbal analogy source and targets. Herein, we had participants verify verbal analogies characterized for semantic distance while we monitored their brain waves using EEG. Our results suggest that the semantic distance between the source and target of a verbal analogy does influence early semantic processing as reflected in the N400 Event-Related Potential. However, successfully differentiating valid and invalid verbal analogies engages areas of prefrontal cortex widely associated with inhibitory processing and the integration of abstract relations in working memory. Thus, it appears that traditional semantic priming alone is likely insufficient to explain the full extent of analogical processing.