Mid-frontal theta is a sensitive marker for cognitive conflict. However, most research focuses on cognitive control paradigms (e.g., the Flanker task). Here, we ask if mid-frontal theta is also sensitive to response conflicts within value-based decision-making. We recorded electroencephalography activity during a value-based binary decision task. In this task, participants collected rewards in a virtual two-dimensional world. In each trial, we presented two reward options that were either quick to collect but were smaller in value, or took longer to collect but were larger in value. The subjective value of each option was driven by the options' value and how quickly it could be reached. We used this task to investigate three types of potential conflicts: choice ambiguity, choice repetitions, and temporal delay. We manipulated choice ambiguity by varying the subjective values of the decision options. For choice repetition, we biased participants toward one option for two trials and then tested how that affected the subsequent decision. We manipulated temporal delay by making one option quick to collect and one longer to collect. The behavioral results showed the expected effects: Decision times were shorter for unambiguous choices, participants showed a tendency to repeat the previous choice and decision times were shorter for repetitions, and decision times were shorter for earlier available choices. Response-locked mid-frontal theta power was increased for choice switches as compared to choice repetitions, and for the later available as compared to the earlier available option, but we found no effect of ambiguity.

中额叶θ是认知冲突的敏感标志。然而，大多数研究都集中在认知控制范式上（例如，侧翼任务）。在这里，我们询问中额叶 theta 是否也对基于价值的决策中的反应冲突敏感。我们在基于价值的二元决策任务中记录了脑电图活动。在这项任务中，参与者在虚拟的二维世界中收集奖励。在每次试验中，我们提供了两种奖励选项，一种是收集速度快但价值较小，另一种是收集时间较长但价值较大。每个选项的主观价值取决于选项的价值以及达到的速度。我们使用此任务来调查三种类型的潜在冲突：选择歧义、选择重复和时间延迟。我们通过改变决策选项的主观值来操纵选择歧义。对于选择重复，我们让参与者在两次试验中偏向一个选项，然后测试这如何影响随后的决定。我们通过使一个选项快速收集和一个更长的收集时间来操纵时间延迟。行为结果显示了预期效果：明确选择的决策时间更短，参与者表现出重复先前选择的倾向，重复的决策时间更短，早期可用选择的决策时间更短。与选择重复相比，选择开关的响应锁定中间额叶 theta 功率增加，与较早可用的选项相比，较晚可用的选项增加，但我们没有发现歧义的影响。