The cause of island effects has evoked considerable debate within syntax and other fields of linguistics. The two competing approaches stand out: the grammatical analysis; and the working-memory (WM)-based processing analysis. In this paper we report three experiments designed to test one of the premises of the WM-based processing analysis: that the strength of island effects should vary as a function of individual differences in WM capacity. The results show that island effects present even for L2 learners are more likely attributed to grammatical constraints than to limited processing resources.
