Previous studies have investigated sequence effect on task switching and found that increased cognitive control in preceding trials would transfer to the current trial. However, it remains unclear whether response variations during task repetition can enhance cognitive control and promote task switching. In the present study, we designed two sequence contexts, the response-change (r-change) and response-repeat (r-repeat) contexts, by adopting a classical task-switching paradigm in which participants were asked to make an odd-even or large-small judgment of the presented digit. The only difference between the two sequence contexts was whether responses varied frequently during task repetition. Behavioral results showed that the r-change context induced smaller switch costs and higher accuracy for task switching than the r-repeat context. Event-related potential (ERP) results revealed (1) the effect of context on N2 amplitudes, with greater N2 in the r-change context than the r-repeat context at frontal-central regions; (2) the interaction between context and transition type during the stimulus-locked P3 component, with a marked context effect for the task-switch trials; (3) non-significant context effect on task switching during the response-locked P3 component. These findings suggest that response variations during a sequence of task-repeat trials can trigger the increase in cognitive control that promotes the efficiency of followed task switching.

先前的研究调查了序列对任务切换的影响，发现先前试验中增强的认知控制将转移到当前试验中。但是，仍不清楚任务重复期间的响应变化是否可以增强认知控制并促进任务切换。在本研究中，我们通过采用经典的任务切换范式设计了两个序列上下文，即响应更改（r-change）和响应重复（r-repeat）上下文，在该范式中，要求参与者使奇数-偶数或显示数字的大小判断。这两个序列上下文之间的唯一区别是任务重复期间响应是否频繁变化。行为结果表明，与r-repeat上下文相比，r-change上下文导致较小的切换成本和更高的任务切换精度。事件相关电位（ERP）的结果表明：（1）情境对N2幅值的影响，r变化情境中的N2比额中中心区域的r重复情境更大；（2）刺激锁定的P3组件中情境和过渡类型之间的交互作用，对于任务切换试验具有明显的情境效应；（3）在响应锁定的P3组件期间，上下文对任务切换的影响不显着。这些发现表明，一系列重复任务试验期间的反应差异可能触发认知控制的增加，从而提高后续任务转换的效率。（2）刺激锁定的P3组件中情境和过渡类型之间的交互作用，对于任务切换试验具有明显的情境效应；（3）在响应锁定的P3组件期间，上下文对任务切换的影响不显着。这些发现表明，一系列重复任务试验期间的反应差异可能触发认知控制的增加，从而提高后续任务转换的效率。（2）刺激锁定的P3组件中情境和过渡类型之间的交互作用，对于任务切换试验具有明显的情境效应；（3）在响应锁定的P3组件期间，上下文对任务切换的影响不显着。这些发现表明，一系列重复任务试验期间的反应差异可能触发认知控制的增加，从而提高后续任务转换的效率。