Do 'deal' and 'dealer' really share their stem? Grammatical class and morphological priming in reading

It is not clear from previous research (e.g., Caramazza et al., 1988; Deutsch et al., 1998; Frost et al., 1997) whether morphological stems that sub-serve the formation of both nouns and verbs (e.g., 'deal-') have a unique, grammatical class-independent representation in the visual word identification system, or rather feature two separate, grammatical-class specific representations. In a first experiment, participants were asked to read aloud nouns and verbs that were anticipated by morphologically-related primes belonging to the opposite grammatical class (e.g., partenza-PARTIRE, departure-TO LEAVE). In order to disambiguate genuine morphological priming from semantic facilitation, the same target words were also paired in a second condition with semantically related, but morphologically unrelated primes (e.g., viaggio-PARTIRE, trip-TO LEAVE). Morphological and semantic primes were contrasted with separate sets of control primes. The results showed reliable cross-class morphological priming. This effect was also shown to be independent from whether nouns primed verbs or vice versa, and from SOA (100 ms vs. 300 ms). In a second experiment, cross-class morphological priming was shown to emerge even when the related primes were compared with control words that shared their orthographic and phonological onset (e.g., abbraccio-ABBRACCIARE, (the) hug-to hug vs. abbazia-ABBRACCIARE, abbey-to hug), thus proving to hold independently of orthography and phonology.