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Abstract:
Task switching paradigms offer an experimental window into the dynamics of cognitive flexibility. A key finding is that when switching from one task to another, participants exhibit a degradation in performance, even when given ample time to prepare for the switch. One hypothesis is that this “residual switch cost” stems from structural constraints on the cognitive system. However, an alternative hypothesis, which fits well with modern views on the costs of cognitive control, suggests the residual switch cost has a strategic origin. That is, timely preparation for a task switch incurs effort and/or opportunity costs, thus participants might choose not to do so, at least on some proportion of trials, unless adequately compensated. To demonstrate effort-sensitive, strategic control over task preparation, studies have aimed to offset the cost of preparation by offering monetary reward for responding by a deadline and observed reduced switch costs. However, rather than promoting timely preparation, such response deadlines might instead encourage speed-accuracy trade-offs following task preparation. A review of existing experiments involving reward and deadlines provides inconclusive results about how these factors influenced task switching performance. We therefore conducted a new experiment to provide a more sensitive test of the different hypotheses. Our data support a model in which response deadline for earning monetary reward affects speed-accuracy trade-off, while the preparatory process is unaffected. Accordingly, we argue that a reduction in switch cost due to reward-associated response deadlines does not necessarily provide evidence for strategic adjustment of task preparation. More generally, our approach demonstrates the utility of detailed modeling in conjunction with empirical testing in evaluating hypotheses concerning the dynamics of cognitive flexibility.
