Discontinuous morphology in time: Incremental masked priming in Arabic

Semitic morphology is based on the combination of two abstract discontinuous morphemes, the word pattern and the root. The word pattern specifies the phonological structure and morpho-syntactic properties of the surface form, while the consonantal root conveys core semantic information. Both units play a crucial role in processing Semitic languages such as Arabic and Hebrew. Here we use incremental masked priming to probe the time-course of word pattern and root activation in reading Arabic deverbal nouns and verbs. The morphological (word pattern and root), orthographic, and semantic relationship between prime and targets is varied over four stimulus onset asynchronies (SOAs) (32, 48, 64, and 80 ms). Results show distinctive patterns of activation for the two morphemic entities. Word pattern effects are transient, and detectable only at SOAs 48 and 64 in deverbal nouns and SOA 48 in verbs. Root effects are strong at all SOAs. This may reflect differences in the timing with which word pattern and root information can be extracted from the orthographic input, as well as differences in the roles of these morphemes in building internal lexical representations. Both types of morphemic effect contrast strongly with the effects of orthographic and semantic primes, where reliable facilitation is only obtained at the longest SOA (80 ms). The general pattern of results is consistent with the view that morphological effects in Semitic languages represent distinct structural characteristics of the language.