From lexicon to phrase: Behavioral evidence for a dynamic cognitive mechanism underlying language control.

This study examined language control at both lexical and phrasal levels, and their relationships with general cognitive control. Thirty-three participants completed two picture-naming tasks assessing lexical and phrasal control. We measured mixing costs (i.e., the index of proactive language control) and switch costs (i.e., the index of reactive language control), and examined their relationships with general proactive cognitive control, assessed by the Proactive Behavioral Index (PBI) from the AX-CPT task, and with general reactive cognitive control, assessed by Stroop scores from the Stroop task. Results revealed greater L1 than L2 mixing costs at both linguistic levels. Switch costs were symmetrical at the lexical level but asymmetrical at the phrasal level. PBI predicted mixing costs at both linguistic levels, whereas Stroop scores predicted switch costs only at the phrasal level. These findings suggest that bilinguals rely on proactive control to monitor bilingual lexical competition, whereas both proactive and reactive control are engaged at the phrasal level. This study proposes a hypothesis that control demands vary across linguistic levels, influencing the adaptation of language control mechanisms and their relationships with general cognitive control.