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Can a single adjective immediately influence message-building during sentence processing? We presented participants with 168 sentence contexts, such as "His skin was red from spending the day at the …" Sentences ended with either the most expected word ("beach") or a low cloze probability completion ("pool"). Nouns were preceded by adjectives that changed their relative likelihood (e.g., "neighborhood" increases the cloze probability of pool whereas "sandy" promotes beach). We asked if participants' online processing can be rapidly updated by the adjective, changing the resulting pattern of facilitation at the noun, and, if so, whether updates unfold symmetrically--not only increasing, but also decreasing, the fit of particular nouns. We measured event-related potentials (ERPs) to the adjective and the noun and modeled these with respect to (a) the overall amount of updating promoted by the adjective, (b) the preadjectival cloze probability of the noun and, (c) the amount of cloze probability change for the obtained noun after the adjective. Bayesian mixed-effects analysis of N400 amplitude at the noun revealed that adjectives rapidly influenced semantic processing of the noun, but did so asymmetrically, with positive updating (reducing N400 amplitudes) having a greater effect than negative updating (increasing N400s). At the adjective, the amount of (possible) updating was not associated with any discernible ERP modulation. Overall, these results suggest the information provided by adjectives is buffered until a head noun is encountered, at which point the access of the noun's semantics is shaped in parallel by both the adjective and the sentence-level representation.

We used eye tracking to investigate the downstream processing consequences of encountering noun/verb (NV) homographs (i.e., park) in semantically neutral but syntactically constraining contexts. Target words were followed by a prepositional phrase containing a noun that was plausible for only 1 meaning of the homograph. Replicating previous work, we found increased first fixation durations on NV homographs compared with unambiguous words, which persisted into the next sentence region. At the downstream noun, we found plausibility effects following ambiguous words that were correlated with the size of a reader's first fixation effect, suggesting that this effect reflects the recruitment of processing resources necessary to suppress the homograph's context-inappropriate meaning. Using these same stimuli, Lee and Federmeier (2012) found a sustained frontal negativity to the NV homographs, and, on the downstream noun, found a plausibility effect that was also positively correlated with the size of a reader's ambiguity effect. Together, these findings suggest that when only syntactic constraints are available, meaning selection recruits inhibitory mechanisms that can be measured in both first fixation slowdown and event-related potential ambiguity effects.

Eye tracking was used to investigate how younger and older (60 or more years) adults use syntactic and semantic information to disambiguate noun/verb (NV) homographs (e.g., "park"). In event-related potential (ERP) work using the same materials, Lee and Federmeier (2009, 2011) found that young adults elicited a sustained frontal negativity to NV homographs when only syntactic cues were available (i.e., in syntactic prose); this effect was eliminated by semantic constraints. The negativity was only present in older adults with high verbal fluency. The current study shows parallel findings: Young adults exhibit inflated first fixation durations to NV homographs in syntactic prose, but not semantically congruent sentences. This effect is absent in older adults as a group. Verbal fluency modulates the effect in both age groups: High fluency is associated with larger first fixation effects in syntactic prose. Older, but not younger, adults also show significantly increased rereading of the NV homographs in syntactic prose. Verbal fluency modulates this effect as well: High fluency is associated with a reduced tendency to reread, regardless of age. This relationship suggests a trade-off between initial and downstream processing costs for ambiguity during natural reading. Together the eye-tracking and ERP data suggest that effortful meaning selection recruits mechanisms important for suppressing contextually inappropriate meanings, which also slow eye movements. Efficacy of frontotemporal circuitry, as captured by verbal fluency, predicts the success of engaging these mechanisms in both young and older adults. Failure to recruit these processes requires compensatory rereading or leads to comprehension failures (Lee & Federmeier, 2012).

Researchers using lateralized stimuli have suggested that the left hemisphere is sensitive to sentence-level context, whereas the right hemisphere (RH) primarily processes word-level meaning. The authors investigated this message-blind RH model by measuring associative priming with event-related brain potentials (ERPs). For word pairs in isolation, associated words elicited more positive ERPs than unassociated words with similar magnitudes and onset latencies in both visual fields. Embedded in sentences, these same pairs showed large sentential context effects in both fields. Small effects of association were observed, confined to incongruous sentences after right visual hemifield presentation but present for both congruous and incongruous sentences after left visual hemifield presentation. Results do not support the message-blind RH model but do suggest hemispheric asymmetries in the use of word and sentence context during real-time processing.