Compound words and structure in the lexicon

The structure of lexical entries and the status of lexical decomposition remain controversial. In the psycholinguistic literature, one aspect of this debate concerns the psychological reality of the morphological complexity difference between compound words (teacup) and single words (crescent). The present study investigates morphological decomposition in compound words using visual lexical decision with simultaneous magnetoencephalography (MEG), comparing compounds, single words, and pseudomorphemic foils. The results support an account of lexical processing which includes early decomposition of morphologically complex words into their constituent parts. The behavioral differences suggest internally structured representations for the compound words, and the early effects of constituents in the electrophysiological signal support the hypothesis of an early morphological parse. The former findings add to a growing literature suggesting that the lexicon includes structured representations, and the latter is consistent with the interesting literature which points to early morphological parsing using other tasks. The results do not favor two of the putative constraints on decomposition, word length and lexicalization, as constraints on early morphological-structure based computation.