The multitasking myth

The idea that people can perform multiple cognitive tasks simultaneously is one of the most widespread and least evidence-backed productivity narratives. What the brain does when it appears to be multitasking is actually switching rapidly between tasks, with each switch generating a cognitive cost that researchers call "task-switching cost." That cost is small per individual switch but accumulates significantly throughout the day.

The most cited study on the subject, published by researchers from the American Psychological Association, found that knowledge workers who alternated between complex tasks lost up to 40% of their productive time in those transition costs. The loss is not felt as such because the state of constant alternation generates a sense of activity and alertness that many people confuse with productivity. The feeling of being busy is not the same as producing results.

The impact on stress is another axis of the problem. Constant task-switching keeps the nervous system in a state of heightened activation that, sustained over hours, contributes to mental fatigue and burnout. Strategies like "deep work" — time blocks dedicated to a single task without interruptions — or the Pomodoro technique — short iterations of total focus — are practical responses with empirical support. They do not eliminate the need to manage multiple responsibilities, but change the execution pattern to minimise transition costs.