| Lexical processing can be facilitated by word-word relationships as well as message-level context. The experiments presented here sought to determine how word-word association and discourse congruity influence the reading process on-line. To assess this processing, ERPs and eye-tracking methodologies were used in parallel studies. These methods provide high temporal resolution and rich data sets from which to infer reading processes. Experiments 1 and 2 examined the processing of sentence-final words that varied in association with a preceding word and overall discourse congruity, using ERPs and eye-tracking, respectively. The manipulation of association took place locally, with only one to three words intervening between the prime and the target. Discourse congruence was manipulated by changing the first two sentences of the passage, while the sentence containing the critical word was always congruous when read in isolation. For Experiments 3 and 4, eye-tracking measures were analyzed for mid-sentence target words. In Experiment 3, these words were embedded in multi-sentence passages, and they varied in discourse congruence and association. For the fourth experiment, associated and unassociated word pairs were presented in isolated sentences without a manipulation of congruity. Effects of discourse congruity were robust in all experiments where that factor was manipulated. In ERPs this resulted in voltage differences in the 150--250 ms latency window, as well as the classic N400 epoch (300--500 ms). In the eye-tracking studies differences in first-pass reading measures were found in the target region far sentence-final words and the post-target region for sentence-final and mid-sentence incongruities. Association, on the other hand, only had significant effects on the N400 in congruent cases. Effects of association for incongruent words were only marginal in the N400 time window, becoming significant in the LPC epoch (500--900 ms). For words embedded in passages, association had a marginal effect on first-pass reading of sentence-final words, but not mid-sentence words. Finally, significant effects of association were found for word pairs embedded in isolated sentences. Therefore, while effects of discourse congruence were robust across methods and sentential position, the effects of association were more tenuous. These results highlight the importance of global, discourse representations on lexical processing. |
