Multitasking situations, such as using one’s phone while driving, are increasingly common in everyday life. Experimental psychology has long documented the costs of multitasking on task performance; however, little is known of the effects it has on the metacognitive processes that monitor such performance. The present study is a step toward filling this void by combining psychophysical procedures with complex multitasking. We devised a multimodal paradigm in which participants performed a sensorimotor tracking task, a visual discrimination task, and an auditory 2-back working memory task, either separately or concurrently, while also evaluating their task performance every ~15 s. Our main finding is that multitasking decreased participants’ awareness of their performance (metacognitive sensitivity) for all three tasks. Importantly, this result was independent of the multitasking cost on task performance, and could not be attributed to confidence leak, psychological refractory period, or recency effects on self-evaluations. We discuss the implications of this finding for both metacognition and multitasking research.

多任务处理情况，例如在开车时使用手机，在日常生活中越来越普遍。实验心理学早就记录了多任​​务处理对任务绩效的成本；然而，人们对它对监测这种表现的元认知过程的影响知之甚少。本研究是通过将心理物理程序与复杂的多任务处理相结合来填补这一空白的一步。我们设计了一种多模态范式，其中参与者分别或同时执行感觉运动跟踪任务、视觉辨别任务和听觉 2-back 工作记忆任务，同时每隔约 15 秒评估他们的任务表现。我们的主要发现是，多任务处理降低了参与者对所有三项任务的表现（元认知敏感性）的认识。重要的，这一结果与任务绩效的多任务成本无关，不能归因于信心泄漏、心理不应期或对自我评价的新近效应。我们讨论了这一发现对元认知和多任务研究的影响。