ERP index of the morphological family size effect during word recognition

► We examined whether the N400 is affected by the semantic richness of associated neighbors. ► We also investigated the source of the different LPC in respect to the semantic richness. ► The number of orthographic neighbors and semantic neighbors are orthogonally manipulated. ► N400 reflects the syllable neighborhood density and the LPC reflects the semantic richness. ► P200 reflects the syllable frequency as in previous findings.