When processing of two tasks overlaps, performance is known to suffer. In the well-established psychological refractory period (PRP) paradigm, tasks are triggered by two stimuli with a short temporal delay (stimulus onset asynchrony; SOA), thereby allowing control of the degree of task overlap. A decrease of the SOA reliably yields longer RTs of the task associated with the second stimulus (Task 2) while performance in the other task (Task 1) remains largely unaffected. This Task 2-specific SOA effect is usually interpreted in terms of central capacity limitations. Particularly, it has been assumed that response selection in Task 2 is delayed due to the allocation of less capacity until this process has been completed in Task 1. Recently, another important factor determining task prioritization has been proposed—namely, the particular effector systems associated with tasks. Here, we study both sources of task prioritization simultaneously by systematically combining three different effector systems (pairwise combinations of oculomotor, vocal, and manual responses) in the PRP paradigm. Specifically, we asked whether task order-based task prioritization (SOA effect) is modulated as a function of Task 2 effector system. The results indicate a modulation of SOA effects when the same (oculomotor) Task 1 is combined with a vocal versus a manual Task 2. This is incompatible with the assumption that SOA effects are solely determined by Task 1 response selection duration. Instead, they support the view that dual-task processing bottlenecks are resolved by establishing a capacity allocation scheme fed by multiple input factors, including attentional weights associated with particular effector systems.

当两个任务的处理重叠时，性能会受到影响。在公认的心理不应期（PRP）范例中，任务由两个刺激以短时间延迟（刺激发作异步； SOA）触发，从而可以控制任务重叠的程度。SOA的减少会可靠地产生与第二刺激（任务2）相关的任务的更长的RT，而其他任务（任务1）的性能在很大程度上不会受到影响。任务2特有的SOA效果通常根据中央容量限制来解释。特别是，假设任务2中的响应选择由于分配较少的容量而延迟，直到任务1中的此过程完成为止。最近，提出了确定任务优先级的另一个重要因素-即，与任务相关的特定效应器系统。在这里，我们通过在PRP范式中系统地组合三个不同的效应器系统（动眼，声音和手动响应的成对组合）同时研究任务优先级的两个来源。具体来说，我们询问是否根据任务2效应器系统对基于任务顺序的任务优先级（SOA效果）进行了调制。结果表明，当相同的（动眼动的）任务1与人声任务与手动任务2相结合时，SOA效果得到了调节。这与SOA效果仅由任务1响应选择持续时间确定的假设不符。相反，他们支持以下观点：通过建立由多个输入因素提供的容量分配方案，可以解决双重任务处理瓶颈，