2Department of Experimental Psychology, University of Oxford, Oxford

Grainger and Beauvillain (1987) found performance costs in the lexical decision task when bilingual participants switched languages in recognizing words. They also found that these costs could be eliminated by the use of language-specific orthographic cues. This led to the suggestion that switch costs arise from within the bilingual lexicon. An alternative account is that switch costs arise from outside the lexicon, a result of competition between control structures put in place to coordinate activation of the lexicon with task-appropriate responses (Green, 1998a, 1998b; Von Studnitz & Green, 1997). In Experiment 1 using English-French bilinguals, we showed that the apparent role of orthographic cues in Grainger and Beauvillain’s study was probably due to a missing control condition. With this control condition in place, language-specific orthography did not reduce the switch cost. Two further experiments investigated the locus of the switch cost and found support for the notion that most of the switch cost originates from outside rather than inside the bilingual lexicon.