Four experiments investigated the extent to which a limited pool of resources can be shared between different tasks performed simultaneously when it is efficient to do so. The experiments used a prioritized processing paradigm, in which stimuli for both a primary task and a background task were presented in each trial. If the primary-task stimulus required a response in a trial, participants made only that response. If the primary-task stimulus did not require a response, participants responded to the background task. The main manipulation was the relative probability that a response would be required to the primary versus background task. In some blocks, the majority of trials required responses to the primary task (Experiments 1 and 2: 80%; Experiments 3 and 4: 60%), whereas in other blocks the majority required responses to the background task. Background-task responses were substantially faster in blocks where they were more likely to be required, consistent with the idea that more capacity was allocated to them in these blocks. Backward compatibility effects on primary-task responses and stimulus-onset asynchrony effects on background-task responses provided further evidence of greater capacity allocation to the background task when there was a higher probability of responding to it. The results support the view that two tasks can be processed in parallel, with resources divided between them, when it is efficient to do so.

四个实验研究了在有效时同时执行的不同任务之间可以共享有限资源池的程度。实验使用优先处理范例，其中在每个试验中都显示了主要任务和背景任务的刺激。如果主要任务刺激在试验中需要响应，则参与者仅做出响应。如果主要任务刺激不需要响应，则参与者对后台任务做出响应。主要操作是需要对主要任务与后台任务做出响应的相对概率。在某些区块中，大多数试验需要对主要任务做出响应（实验1和2：80％；实验3和4：60％），而在其他区块中，大多数则需要对后台任务做出响应。后台任务响应在更可能需要它们的块中快得多，这与在这些块中为其分配更多容量的想法一致。对主要任务响应的向后兼容效应和对后台任务响应的刺激发作异步效应提供了进一步的证据，即当有更高的响应可能性时，将更大的容量分配给后台任务。结果支持这样的观点，即可以高效地并行处理两个任务，并且可以在两个任务之间分配资源。对主要任务响应的向后兼容效应和对后台任务响应的刺激发作异步效应提供了进一步的证据，即当有更高的响应可能性时，将更大的容量分配给后台任务。结果支持这样的观点，即可以高效地并行处理两个任务，并且可以在两个任务之间分配资源。对主要任务响应的向后兼容效应和对后台任务响应的刺激发作异步效应提供了进一步的证据，即当有更高的响应可能性时，将更大的容量分配给后台任务。结果支持这样的观点，即可以高效地并行处理两个任务，并且可以在两个任务之间分配资源。