Multitasking makes you more productive

What we know

Multitasking is commonly framed as a valuable productivity skill, particularly in professional and educational contexts, with some people describing themselves as effective "multitaskers." Cognitive psychology research directly contradicts the idea that simultaneously performing multiple attention-demanding tasks improves overall efficiency. The brain does not truly process two complex cognitive tasks in parallel in most cases; instead, what feels like multitasking is typically rapid task-switching, and switching itself carries a measurable cognitive cost, described in the research literature as "switch cost."

Foundational research by psychologist David Meyer and colleagues at the University of Michigan in the late 1990s and early 2000s used controlled experiments requiring participants to switch between two simple tasks, and found that task-switching consistently slowed overall completion time and increased error rates compared with completing the same tasks sequentially without switching, with the time cost increasing as task complexity increased. Stanford researcher Clifford Nass's influential study, published in the Proceedings of the National Academy of Sciences in 2009, compared self-identified heavy multitaskers with light multitaskers on tasks requiring filtering irrelevant information, task-switching, and working memory, and found heavy multitaskers performed worse across all three measures, undermining the assumption that frequent multitasking practice makes someone better at it.

Research on multitasking while driving, particularly cell phone use, has produced some of the most consequential and widely replicated findings in this area: studies commissioned by the National Highway Traffic Safety Administration and published in peer-reviewed journals consistently find that phone use while driving, including hands-free calling, measurably impairs reaction time and hazard detection comparable in some studies to alcohol-impaired driving at the legal limit, evidence with direct real-world safety implications beyond general productivity concerns.

The apparent contradiction between people's subjective sense that multitasking works for them and the consistent experimental finding that it does not is itself a well studied phenomenon: people are generally poor at accurately assessing their own multitasking performance, in part because task-switching happens quickly enough that the accumulated time cost and error increase are not consciously noticed in the moment, and heavy multitaskers in Nass's research were actually the least accurate at self-assessing their own multitasking ability. Some tasks that are highly automatic and require minimal conscious attention, such as walking while having a casual conversation, can be combined without meaningful performance loss, because they do not compete for the same limited cognitive resources; this is different from combining two attention-demanding tasks like writing an email while participating in a meeting, which is the type of multitasking research consistently finds is less efficient than sequential focused work, not more. Workplace productivity researchers have extended this laboratory finding into organizational studies, finding that interruptions and context-switching between different projects during a workday measurably lengthen the time needed to complete each individual task compared with blocks of uninterrupted focused work, a pattern with direct relevance to common assumptions about email and messaging-driven work environments.

Common claims

• Doing multiple things at once saves time.False. Task-switching costs outweigh any apparent time savings for complex tasks.
• Some people are natural multitaskers who suffer no cognitive cost.False. Heavy multitaskers typically perform worse on sustained-attention tasks.
• Multitasking simple tasks with complex ones is efficient.Partly true. Automatic tasks paired with demanding ones carry lower switching costs.

Evidence hierarchy

All sources

• Cognitive control in media multitaskersEyal Ophir, Clifford Nass, and Anthony Wagner, Proceedings of the National Academy of Sciences · 2009
• Executive control of cognitive processes in task switchingRubinstein, Meyer, and Evans, Journal of Experimental Psychology · 2001
• Distracted DrivingNational Highway Traffic Safety Administration · 2023
• American Psychological Association resources on multitasking researchAmerican Psychological Association · 2022

Related terms