Reading Comprehension and Predictability Effects on Sentence Processing: An Event-Related Potential Study

Electrophysiology studies have identified two event-related potentials that are modulated by predictive processes during language comprehension: the N400 and a frontal positivity. The N400 is smaller when words are presented within highly restrictive sentences, indicating reduced lexical retrieval costs. Violations of strong predictions generate larger frontal positivities, possibly reflecting inhibitory processes. More skilled comprehenders may exhibit enhanced predictive processing, but this possibility has seldom been investigated with event-related potentials (ERPs). We analyzed the association between predictability ERP modulations and reading comprehension abilities. Twenty-four undergraduate students were exposed to strongly and weakly constraining sentences, ending with an expected or unexpected final word. Their comprehension skills were assessed with a cloze task. Better comprehenders showed smaller N400s for expected words, and larger posterior positivities for unexpected endings, in strongly constraining contexts. These effects correlated with reading comprehension scores. The results suggest that better comprehenders take more advantage of predictions to reduce retrieval costs, and allocate more resources to postlexical integration processes.