Investigating the Impact of Bilingual Experience and Language Use Context on Cognitive Control in an Auditory Stroop Task

Bilinguals are often reported to outperform monolinguals on executive control tasks, yet recent work suggests that any bilingual adaptations depend on how, and in which contexts, individuals use their two languages. The present dissertation tested whether specific dimensions of bilingual experiences (proficiency balance and daily interaction situations) predict the way listeners engage proactive (anticipatory) versus reactive (stimulus-driven) control when resolving non-linguistic conflict. Sixty young adults completed a non-linguistic auditory Stroop task that manipulated conflict expectancy both list-wide and item-specifically. Group-level analysis replicated classic proportion-congruency effects, but not the predicted proactive control signature, and transfer cost indexing reactive control was not observed. Crucially, multivariate models revealed that these effects masked systematic individual differences. More balanced bilinguals and those who navigate high-control settings showed (a) greater trial-to-trial variability, and (b) uniformly small interference across items and blocks - consistent with a generalized, proactive control mode. Task order did not influence any interference or variability measure, suggesting that the auditory Stroop paradigm is resilient to transient cognitive-fatigue effects. Findings refine the Adaptive Control Hypothesis by showing that proactive mechanisms emerge primarily in bilinguals who are both highly balanced and habitually manage language choice, whereas reactive strategies persist when linguistic demands are lower. Methodologically, they demonstrate that a nonlinguistic auditory Stroop task with proportion congruency manipulations sensitively captures experience-dependent differences overlooked by visual paradigms. Implications for measuring bilingualism and modeling control dynamics across sensory modalities are discussed.