Previous studies have shown that the probability of task switching can vary the level of cognitive control and modulate the size of switch costs. However, it is unclear whether switch costs would be affected by a task‐repetition context formed by varying the degree of response (and task‐relevant stimulus property) change within the task repetition sequences while the probability of task switching remains constant. In the present study, participants were presented with a string of digits (e.g., ②②②). Basing on stimulus color, they were required to indicate either the presented digit, or the number of presented digits. Before task switching, stimulus and response in consecutive task‐repeat trials varied more or less frequently. Behavioral results showed that the frequent‐change context elicited smaller switch costs than the rare‐change context. Event‐related potential (ERP) results indicated that: (1) the frequent‐change context evoked greater fronto‐central N2 amplitudes for both task‐repeat and task‐switch trials, implying that cognitive control increased due to the variation of stimulus and response associations; (2) for the task switch trials, smaller P300 amplitudes were evoked in the frequent‐change context than the rare‐change context, reflecting the promoted task‐set reconfiguration. These findings suggest that, the more change in stimulus and response during task repetition, the higher the overall level of cognitive control and the higher efficiency of task‐switching.

中文翻译：

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任务重复的更多变化，任务切换的成本更低：与行为和事件相关的潜在证据

先前的研究表明，任务转换的可能性可以改变认知控制的水平并调节转换成本的大小。但是，目前尚不清楚切换成本是否会受到任务重复上下文的影响，而任务重复上下文是通过改变任务重复序列中响应（和与任务相关的刺激属性）变化的程度而形成的，而任务切换的可能性保持不变。在本研究中，向参与者展示了一系列数字（例如，②②②）。根据刺激颜色，要求它们指示显示的数字或显示的数字。在任务切换之前，连续任务重复试验中的刺激和反应或多或少地频繁变化。行为结果表明，频繁变化的情境比稀有变化的情境所引起的转换成本要小。事件相关电位（ERP）结果表明：（1）频繁变化的情境在任务重复和任务转换试验中引起额中心N2幅度更大，这表明由于刺激和反应的变化，认知控制增加了协会；（2）对于任务切换试验，在频繁变化的情况下引起的P300幅度比稀有变化的情况要小，这反映出任务集重新配置得到了促进。这些发现表明，任务重复过程中刺激和响应的变化越多，认知控制的总体水平越高，任务切换的效率越高。暗示由于刺激和反应关联的变化，认知控制有所增强；（2）对于任务切换试验，在频繁变化的情况下引起的P300幅度比稀有变化的情况要小，这反映出任务集重新配置得到了促进。这些发现表明，任务重复过程中刺激和响应的变化越多，认知控制的总体水平越高，任务切换的效率越高。暗示由于刺激和反应关联的变化，认知控制有所增强；（2）对于任务切换试验，在频繁变化的情况下引起的P300幅度比稀有变化的情况要小，这反映出任务集重新配置得到了促进。这些发现表明，任务重复过程中刺激和响应的变化越多，认知控制的总体水平越高，任务切换的效率越高。