Are root letters compulsory for lexical access in Semitic languages? The case of masked form-priming in Arabic

Do Semitic and Indo-European languages differ at a qualitative level? Recently, it has been claimed that lexical space in Semitic languages (e.g., Hebrew, Arabic) is mainly determined by morphological constraints, while lexical space in Indo-European languages is mainly determined by orthographic constraints (Frost, Kugler, Deutsch, & Forster, 2005). One of the key findings supporting the qualitative difference between Semitic and Indo-European languages is the absence of masked form priming in Hebrew/Arabic with productive words. Here we examined whether masked form priming occurs in Arabic words when one of the letters from the productive root is replaced in the prime stimulus by another letter. Results showed a significant masked form priming effect with the lexical decision task in three experiments (including yes/no, go/no-go, and sandwich priming), to a similar degree to that reported in previous research with Indo-European languages. These data support the view that the processing of word forms in Semitic vs. Indo-European languages differs more at a quantitative than at a qualitative level.