Multitasking is often treated as a skill some people are simply better at than others. Cognitive science research suggests something less flattering: what we call multitasking is almost never simultaneous processing — it’s rapid switching between tasks, and that switching carries a real cost.
The switching cost, quantified
Research from cognitive psychologists, including work summarized by the American Psychological Association, has found that task-switching can reduce productivity by as much as 40% compared to focused, single-task work, due to the mental overhead of reorienting to each task after an interruption.
Why it feels productive anyway
Task-switching produces a subjective sense of busyness and accomplishment — you’re doing a lot of things — even though objective output measures typically show it’s slower and more error-prone than sequential focused work. This mismatch between feeling and reality is part of why the habit persists despite its cost.
Where it does the most damage
Complex or unfamiliar tasks suffer the most from switching, since they require more working memory to hold in mind; simple, well-practiced tasks are more resilient to interruption.
Practical countermeasures
- Batch similar tasks (all emails, then all calls) rather than interleaving different types of work.
- Turn off notifications during blocks reserved for complex tasks.
- Accept that “doing two things at once” for anything requiring real thought is usually an illusion, not a productivity technique.
The bottom line
What feels like efficient multitasking is typically inefficient switching. Sequential, protected focus time produces better results for anything that requires actual thinking.
