Seeing stems everywhere: Position-independent identification of stem morphemes

There is broad consensus that printed complex words are identified on the basis of their constituent morphemes. This fact raises the issue of how the word identification system codes for morpheme position, hence allowing it to distinguish between words like overhang and hangover, and to recognize that preheat is a word, whereas heatpre is not. Recent data have shown that suffixes are identified as morphemes only when they occur at the ends of letter strings (Crepaldi, Rastle, & Davis, 2010), which supports the general proposal that the word identification system is sensitive to morpheme positional constraints. This proposal leads to the prediction that the identification of free stems should occur in a position‑independent fashion, given that free stems can occur anywhere within complex words (e.g., overdress and dresser). In Experiment 1, we show that the rejection time of transposed-constituent pseudocompounds (e.g., moonhoney) is longer than that of matched control nonwords (e.g., moonbasin), suggesting that honey and moon are identified within moonhoney, and that these morpheme representations activate the representation for the word honeymoon. In Experiments 2 and 3, we demonstrate that the masked presentation of transposed-constituent pseudocompounds (e.g., moonhoney) facilitates the identification of compound words (honeymoon). In contrast, monomorphemic control pairs do not produce a similar pattern (i.e., rickmave did not prime maverick), indicating that the effect for moonhoney pairs is genuinely morphological in nature. These results demonstrate that stem representations differ from affix representations in terms of their positional constraints, providing a challenge to all existing theories of morphological processing.