Multitasking and Memory: Why Task Switching

Why does multitasking make demanding tasks take longer?

Reading an explanation while repeatedly answering messages can feel efficient because both activities keep moving. Yet each transition introduces another demand: identifying the current goal and applying the appropriate mental rules. For tasks requiring deliberate attention, this switching process can reduce the efficiency gained from trying to handle several things together.

In four experiments published in the Journal of Experimental Psychology: Human Perception and Performance in 2001, Joshua Rubinstein, David Meyer and Jeffrey Evans compared alternating between tasks with repeating the same task. Switching introduced measurable time costs, which increased when the rules became more complex. Cues identifying the upcoming task reduced those costs. The researchers proposed that shifting goals and activating task rules help explain the delay. [Rubinstein and colleagues' task-switching study](https://pubmed.ncbi.nlm.nih.gov/11518143/).

The practical implication is that the demands of the activities matter. These experiments do not establish one universal percentage of productivity lost to multitasking, nor do they show that every combination of activities is equally difficult. Their clearest finding concerns the immediate cost of changing between tasks with different rules.

What does research show about multitasking and memory?

A 2020 Nature study led by Kevin Madore examined 80 young adults whose average age was 21.7 years. Researchers recorded brain electrical activity and pupil measurements during memory tasks. Attention lapses immediately before remembering were associated with unsuccessful recall, and participants reporting heavier media multitasking tended to show poorer sustained attention and memory performance. [Madore and colleagues' memory study](https://www.nature.com/articles/s41586-020-2870-z).

The relationship with habitual media use was observational: participants were not randomly assigned to develop different long-term multitasking habits. The results therefore cannot determine whether multitasking caused attention difficulties or whether people with greater attention difficulties were more inclined to multitask. A study of young adults also cannot establish dementia risk later in life.

Other research provides an additional caution. In 2017, Wisnu Wiradhany and Mark Nieuwenstein published two replication studies and a meta-analysis examining media multitasking and distractibility. The pooled association was weak and became statistically nonsignificant after adjustment for small-study effects. This challenges sweeping claims that frequent multitaskers necessarily have impaired cognitive control. It also highlights a crucial distinction: an immediate performance cost while switching tasks does not, by itself, demonstrate a lasting change in a person's underlying abilities. [Replication studies and meta-analysis](https://pmc.ncbi.nlm.nih.gov/articles/PMC5662702/).

How can people reduce the cognitive burden of multitasking?

Harvard Health Publishing recommends choosing a clear priority, setting aside time for it and reducing competing distractions. Practical options include silencing nonessential notifications, removing background television and working in focused intervals separated by breaks. The interval can be adjusted to the person and the task; a particular timer setting should not be treated as a medical prescription. [Harvard Health's guidance on monotasking](https://www.health.harvard.edu/mind-and-mood/the-art-of-monotasking).

The issue can extend beyond productivity. Harvard's guidance highlights how distraction during everyday routines may contribute to mistakes, including forgetting medication or taking it twice, particularly among older adults. Giving such routines dedicated attention is a practical application of reducing interruptions. These strategies aim to make the current activity easier to complete reliably; the studies discussed here do not establish that adopting them prevents dementia or produces a lasting increase in intelligence.