Adaptive behavior requires finding, and adjusting, an optimal tradeoff between focusing on a current task-set (cognitive stability) and updating that task-set when the environment changes (cognitive flexibility). Such dynamic adjustments of cognitive flexibility are observed in cued task-switching paradigms, where switch costs tend to decrease as the proportion of switch trials over blocks increases. However, the learning mechanisms underlying this phenomenon, here referred to as the list-wide proportion switch effect (LWPSE), are currently unknown. We addressed this question across four behavioral experiments. Experiment 1 replicated the basic LWPSE reported in previous studies. Having participants switch between three instead of two tasks, Experiment 2 demonstrated that the LWPSE is preserved even when the specific alternate task to switch to cannot be anticipated. Experiments 3a and 3b tested for the generalization of list-wide switch-readiness to an unbiased “transfer task,” presented equally often as switch and repeat trials, by intermixing the transfer task with biased tasks. Despite the list-wide bias, the LWPSE was only found for biased tasks, suggesting that the modulations of switch costs are task set and/or task stimulus (item)-specific. To evaluate these two possibilities, Experiment 4 employed biased versus unbiased stimuli within biased task sets and found switch-cost modulations for both stimuli sets. These results establish how people adapt their stability-flexibility tradeoff to different contexts. Specifically, our findings show that people learn to associate context-appropriate levels of switch readiness with switch-predictive cues, provided by task sets as well as specific task stimuli.

适应性行为需要找到并调整关注当前任务集（认知稳定性）和在环境变化时更新该任务集（认知灵活性）之间的最佳权衡。在线索任务切换范式中观察到认知灵活性的这种动态调整，其中随着切换试验在块上的比例增加，切换成本趋于降低。然而，这种现象背后的学习机制，这里称为列表范围的比例转换效应（LWPSE），目前尚不清楚。我们通过四个行为实验解决了这个问题。实验 1 复制了先前研究中报告的基本 LWPSE。让参与者在三个而不是两个任务之间切换，实验 2 表明，即使无法预期要切换到的特定替代任务，LWPSE 也会保留。实验 3a 和 3b 测试了列表范围的切换准备对无偏“转移任务”的泛化，通过将转移任务与有偏见的任务混合，同样经常呈现为切换和重复试验。尽管存在列表范围的偏差，但 LWPSE 仅适用于有偏差的任务，这表明转换成本的调制是任务集和/或任务刺激（项目）特定的。为了评估这两种可能性，实验 4 在有偏见的任务集中采用了有偏见的刺激与无偏见的刺激，并为两个刺激集找到了转换成本调制。这些结果确定了人们如何根据不同的环境调整他们的稳定性-灵活性权衡。具体来说，