Temporal predictability optimises behaviour when a simple response is required, as demonstrated by faster reaction times (RTs) and higher accuracy. However, its beneficial effects come at a cost under situations of response conflict. Here, we investigated the motor underpinnings of behaviour to temporally predictable events in the Simon conflict task. We compared motor responses to lateralised targets whose position conflicted (incompatible condition) or not (compatible condition) with the hand of response. Importantly, electromyographic (EMG) recordings allowed us to study "partial errors", defined as subthreshold muscle activity in the incorrect response agonist preceding a correct response. Advanced distributional analyses coupled with EMG data revealed that temporal predictability induced impulsive premature responding, as indexed by increased likelihood of fast incorrect EMG activations (both partial errors and errors) to incompatible targets. In parallel, responding to temporally predictable targets speeded the latency of partial errors, further indicating that temporal predictability increased the tendency to act prematurely. There was, however, no effect of temporal predictability on subsequent suppression of partial errors. Our results provide direct evidence that temporal predictability acts by increasing the urge to initiate a fast, yet potentially erroneous, response. This mechanism parsimoniously explains both beneficial effects of temporal predictability when no conflict in the environment is present, as well as its costs when more complex motor behaviour is required.

中文翻译：

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冲动对肌电图显示的暂时可预测事件作出反应的机制。

当需要简单的响应时，时间可预测性可优化行为，如更快的反应时间（RT）和更高的准确性所证明。然而，在响应冲突的情况下，其有益效果是以牺牲为代价的。在这里，我们调查了西蒙冲突任务中行为对暂时可预测事件的运动基础。我们比较了运动反应与侧向目标的位置，这些目标的位置与响应手发生冲突（不兼容条件）或不冲突（兼容条件）。重要的是，肌电图（EMG）录音使我们能够研究“部分错误”，即被定义为在正确反应之前的错误反应激动剂中的阈下肌肉活动。先进的分布分析以及EMG数据表明，时间可预测性会导致冲动性过早反应，可以通过快速错误地激活不兼容目标的EMG（部分错误和错误）的可能性来进行索引。同时，对时间可预测目标的响应加快了部分错误的等待时间，进一步表明时间可预测性增加了过早采取行动的趋势。但是，时间可预测性对随后抑制部分错误没有影响。我们的结果提供了直接的证据，表明时间可预测性通过增加启动快速但可能错误的响应的冲动而起作用。这种机制简略地解释了在环境中不存在冲突时时间可预测性的有益效果，以及在需要更复杂的运动行为时的时间可预测性。