Dual-task (DT) situations require task-order coordination processes that schedule the processing of two temporally overlapping tasks. Theories on task-order coordination suggest that these processes rely on order representations that are actively maintained and processed in working memory (WM). Preliminary evidence for this assumption stems from DT situations with variable task order, where repeating task order relative to the preceding trials results in improved performance compared to changing task order, indicating the processing of task-order information in WM between two succeeding trials. We directly tested this assumption by varying WM load during a DT with variable task order. In Experiment 1, WM load was manipulated by varying the number of stimulus–response mappings of the component tasks. In Experiment 2A, WM load was increased by embedding an additional WM updating task in the applied DT. In both experiments, the performance benefit for trials with repeated relative to trials with changed task order was reduced under high compared to low WM load. These results confirm our assumption that the processing of the task-order information relies on WM resources. In Experiment 2B, we tested whether the results of Experiment 2A can be attributed to introducing an additional task per se rather than to increased WM load by introducing an additional task with a low WM load. Importantly, in this experiment, the processing of order information was not affected. In sum, the results of the three experiments indicate that task-order coordination relies on order information which is maintained in an accessible state in WM during DT processing.

双任务 (DT) 情况需要任务顺序协调过程来安排两个时间重叠任务的处理。任务顺序协调理论表明，这些过程依赖于在工作记忆 (WM) 中积极维护和处理的顺序表示。这一假设的初步证据源于具有可变任务顺序的 DT 情况，其中相对于先前试验的重复任务顺序与更改任务顺序相比会提高性能，这表明在两次后续试验之间处理 WM 中的任务顺序信息。我们通过在具有可变任务顺序的 DT 期间改变 WM 负载直接测试了这一假设。在实验 1 中，通过改变组件任务的刺激-响应映射的数量来操纵 WM 负载。在实验 2A 中，通过在应用的 DT 中嵌入额外的 WM 更新任务来增加 WM 负载。在这两个实验中，重复的试验相对于改变任务顺序的试验的性能优势在高负荷下与低负荷相比降低了。这些结果证实了我们的假设，即任务顺序信息的处理依赖于 WM 资源。在实验 2B 中，我们测试了实验 2A 的结果是否可以归因于引入额外的任务本身，而不是通过引入具有低 WM 负载的额外任务来增加 WM 负载。重要的是，在这个实验中，订单信息的处理没有受到影响。总之，三个实验的结果表明，任务-顺序协调依赖于在 DT 处理期间在 WM 中保持在可访问状态的顺序信息。