ABSTRACT
Research in visual word recognition has shown that phonological neighborhood density facilitates visual word recognition. The current research was designed to determine the electrophysiological effect of phonological neighborhood density (PND). In two experiments, participants made lexical decisions to words varying on phonological neighborhood while Event-related Potentials (ERPs) were recorded. Behaviorally, the results replicate previous research by showing that words with many phonological neighbors were responded to more rapidly than were words with few phonological neighbors. However, the main contribution of the current research is that it shows an effect of PND on the N400 and Late Positive Component Event-Related Potentials. In contrast to previous reports in the literature, the nature of the effect was such that the N400 was larger to words with few phonological neighbors than to words with many. Experiment 2 replicated these findings and provided estimates of the independent components' time course and source localization. The increased N400 for small neighborhood words is thought to reflect additional semantic processing required for these words due their weaker phonological representations.