Semantic processing of unattended words by bilinguals: A test of the input switch mechanism

In three experiments bilingual subjects were presented stimuli consisting of a target word surrounded above and below by two copies of a to-be-ignored flanker word. Words from four semantic categories were used; two of the categories were assigned to one response while the other two categories were assigned to the second response. The language of the target and flanker words differed on all trials in Experiments 1 and 2 (cross-language flankers), while Experiment 3 involved a comparison between the effects of cross-language and same-language flankers. It was found that target response times were affected by the meaning of the to-be-ignored flanker words, both when the targets and flankers were printed in the same language (Experiment 3) and when they were printed in different languages (Experiments 1–3). It was concluded that this finding is difficult to reconcile with the view that bilinguals possess an “input switch” which operates to switch on processing in just one of their language systems at a time.