Word Wars: The Role of Form and Semantic Encoding in Implicit and Explicit Recognition of Nouns and Verbs

Encoding word form and semantic information is critical for integrating new words into the lexicon. Factors like encoding context and word class impact memory traces and, thus, recognition of new words. This study investigated how encoding form and semantic information in incidental contexts influences later explicit and implicit recognition of novel nouns and verbs. Across two experiments (Noun: n = 31; Verb: n = 23), although explicit semantic encoding did not facilitate behavioral recognition, neural measures (mismatch negativity [MMN], N400) revealed distinct implicit processing patterns for each word class. MMN results indicated word form encoding for nouns but not verbs. N400 results showed that nouns with explicitly identified meanings required more effortful processing, whereas most previously encountered verbs showed evidence of semantic encoding regardless of meaning identification. These findings provide insights into mechanisms underlying word learning and word recognition and illustrate how lexical representation development differs across word classes.