Grainger and Beauvillain (1987) found performance costs in the lexical deci
sion tusk when bilingual participants switched languages in recognizing wor
ds. They also found ih;li these costs could be eliminated by the use of lan
guage-specific orthographic cues. This led to the suggestion that switch co
sts arise from within the bilingual lexicon. An alternative account is that
switch costs arise From outside the lexicon. a result of competition betwe
en control structures pot 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 i
n place, language-specific orthography did not reduce the switch cost. Two
further experiments investigated the locus of the switch cost and found sup
port For the notion that most of the switch cost originates from outside ra
ther than inside the bilingual lexicon. (C) 2000 Academic Press.