Too much of a good thing: Stronger bilingual inhibition leads to larger lag-2 task repetition costs

Inhibitory control and monitoring abilities of Hebrew-English bilingual and English monolingual university students were compared, in a paradigm requiring participants to switch between performing three distinct tasks. Inhibitory control was gauged by lag-2 task repetition costs, namely decreased performance on the final trial of sequences of type ABA relative to CBA, due to persisting inhibition of the recently abandoned task. Bilinguals had larger lag-2 repetition costs, which reflect stronger inhibition of a no-longer relevant task to facilitate a switch into a new task. Monitoring ability was measured by the fadeout effect, which reflects adaptation to simpler task demands when a single task block immediately and unexpectedly follows mixed task blocks. Bilinguals did not differ from monolinguals in the magnitude or trajectory of the fade-out effect. Thus, results support the notion of increased bilingual inhibitory control, even when it is detrimental to performance, and do not demonstrate a specific bilingual advantage in monitoring. These findings are discussed in the context of the recent debate concerning the locus of bilingual advantages.