Almost everyone believes they can multitask, at least a little, and almost everyone is wrong. What actually happens when you "multitask" isn't parallel processing, it's rapid switching between tasks, and that switching carries a real, measurable cost that most people never notice because it happens below conscious awareness.
What your brain is actually doing
With rare exceptions for truly automatic tasks, like walking while talking, your brain handles one cognitively demanding task at a time. What feels like doing two things at once, answering a message while writing a report, is really your attention rapidly toggling back and forth, dropping and reloading context each time. Each switch has a cost known as "switch cost," a brief lag while your brain reorients, and that cost compounds every time you switch back.
Why it feels efficient even though it isn't
Switching feels productive because you're doing visibly more, more apps open, more replies sent, more tabs touched. What it actually produces is more motion, not more output. Studies on task switching consistently find it takes longer to complete two switched-between tasks than to complete them one after another, and the quality of the work drops on both.
The specific cost of a notification, even ignored
You don't need to open a notification for it to cost you focus. The mere appearance of a banner is enough to pull attention away from what you were doing, and research on this effect has found it can take over twenty minutes to fully re-establish deep focus after an interruption, even a brief one you dismissed without reading.
How to actually stop doing it
- Batch similar tasks instead of interleaving them. Answer messages in one block, write in another. Switching between task types is far more costly than switching within the same type.
- Remove the easiest switch, not the hardest one. You're never going to multitask between two spreadsheets, you'll multitask between your work and your phone. That's the switch worth eliminating first.
- Block notifications during focus blocks, not just at night. Most people silence notifications for sleep and leave them fully on during the exact hours they're trying to do deep work.
- Use a visible timer for single-task blocks. Twenty-five to fifty minutes on one task, with your phone genuinely out of reach, produces more finished work than twice that time spent switching.
What single-tasking actually feels like at first
Uncomfortable, honestly. Most people are so used to the constant low-grade switching that sitting with one task for thirty straight minutes feels almost boring by comparison. That discomfort fades within a week or two, and what replaces it is usually described as a kind of quiet that people didn't realize they'd been missing.