There is a lively and theoretically important debate about whether, how, and when embodiment contributes to language comprehension. This study addressed these questions by testing how interference with facial action impacts the brain's real-time response to emotional language. Participants read sentences about positive and negative events (e.g., “She reached inside the pocket of her coat from last winter and found some (cash/bugs) inside it.”) while ERPs were recorded. Facial action was manipulated within participants by asking participants to hold chopsticks in their mouths using a position that allowed or blocked smiling, as confirmed by EMG. Blocking smiling did not influence ERPs to the valenced words (e.g., cash, bugs) but did influence ERPs to final words of sentences describing positive events. Results show that affectively positive sentences can evoke smiles and that such facial action can facilitate the semantic processing indexed by the N400 component. Overall, this study offers causal evidence that embodiment impacts some aspects of high-level comprehension, presumably involving the construction of the situation model.

Grapheme–color synesthesia is a heritable trait where graphemes (“2”) elicit the concurrent perception of specific colors (red). Researchers have questioned whether synesthetic experiences are meaningful or simply arbitrary associations and whether these associations are perceptual or conceptual. To address these fundamental questions, ERPs were recorded as 12 synesthetes read statements such as “The Coca-Cola logo is white and 2,” in which the final grapheme induced a color that was either contextually congruous (red) or incongruous (“…white and 7,” for a synesthetes who experienced 7 as green). Grapheme congruity was found to modulate the amplitude of the N1, P2, N300, and N400 components in synesthetes, suggesting that synesthesia impacts perceptual as well as conceptual aspects of processing. To evaluate whether observed ERP effects required the experience of colored graphemes versus knowledge of grapheme–color pairings, we ran three separate groups of controls on a similar task. Controls trained to a synesthete's associations elicited N400 modulation, indicating that knowledge of grapheme–color mappings was sufficient to modulate this component. Controls trained to synesthetic associations and given explicit visualization instructions elicited both N300 and N400 modulations. Lastly, untrained controls who viewed physically colored graphemes (“2” printed in red) elicited N1 and N400 modulations. The N1 grapheme congruity effect began earlier in synesthetes than colored grapheme controls but had similar scalp topography. Data suggest that, in synesthetes, achromatic graphemes engage similar visual processing networks as colored graphemes in nonsynesthetes and are in keeping with models of synesthesia that posit early feed-forward connections between form and color processing areas in extrastriate cortex. The P2 modulation was unique to the synesthetes and may reflect neural activity that underlies the conscious experience of the synesthetic induction.

Two studies tested the hypothesis that the right hemisphere engages in relatively coarse semantic coding that aids high-level language tasks such as joke comprehension. Scalp-recorded event-related brain potentials (ERPs) were collected as healthy adults read probe words ( CRAZY ) preceded either by jokes or nonfunny controls (“Everyone had so much fun jumping into the swimming pool, we decided to put in a little water/platform ”). Probes were related to the meaning of the jokes, but not the controls. In Experiment 1a, with central presentation, probes following jokes (related) elicited less negative ERPs 300–700 msec postonset (N400) than did probes following nonfunny controls (unrelated). This finding suggests related probes were primed by the jokes. In addition, unrelated probes elicited a larger anterior positivity 700– 900 msec than did related, as irrelevant stimuli impacted control processes invoked by task demands. In Experiment 1b, probes ( CRAZY ) were preceded only by sentence-final words from jokes ( water ) or controls ( platform ). No ERP effects were observed in Experiment 1b, suggesting the N400 priming effect and the anterior positivity observed in Experiment 1a reflect semantic activations at the discourse level. To assess hemispheric differences in semantic activations, in Experiment 2, ERPs were recorded as participants read probe words presented in their left and right visual fields (LVF and RVF, respectively). Probes elicited a smaller N400 component when preceded by jokes than controls. This N400 priming effect was larger with presentation to the LVF, suggesting joke-relevant information was more active in the right hemisphere. The anterior positivity was observed with RVF but not LVF presentation, suggesting an important role for the left hemisphere in controlled retrieval in language comprehension.