Context-Specific Adjustments of Cognitive Flexibility
The stability-flexibility dilemma describes the challenge of balancing the antagonistic goals of focusing on the current task-set (cognitive stability) and updating that task-set in response to changes in the environment (cognitive flexibility). Dynamic adjustments of cognitive flexibility are observed in cued task-switching paradigms, wherein switch costs, or the performance costs associated with switching between tasks, have been shown to decrease as the proportion of switch trials within a block increase. This effect is referred to as the list-wide proportion switch (LWPS) effect, and presents evidence of meta-flexibility, or people’s ability to find an optimal level of flexibility based on contextual demands. While context-sensitive control adaptations have been extensively researched in the conflict literature, fewer studies have been dedicated to investigating such flexibility adaptations. Consequently, the underlying mechanisms of meta-flexibility remain unknown. Across four behavioral experiments, Chapter 2 teases apart the different levels of learning that may contribute to list-wide flexibility adaptations, controlling for stimulus- and task-level associations. Chapter 3 investigates the EEG neural signatures of meta-flexibility. In Chapter 4, we test for whether learned flexibility adjustments benefit from memory consolidation, like other forms of associative learning. Lastly, Chapter 5 utilized three novel behavioral paradigms to investigate different conditions under which flexibility learning transfers or fails to transfer. Collectively, the results in this dissertation suggest that flexibility adjustments to contextual demands occurs rapidly and transfers reliably across novel stimuli, such that, in high switch frequency blocks, participants could perform more rapid task switches even on trials involving items never seen before. However, both behavioral and neural evidence suggest that flexibility learning is also task specific, such that switch performance boosts to tasks that appear more often as switch trials do not generalize to other tasks that occur in the same temporal contexts.
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