What is task switching?
Task switching is moving attention from one task to another before the first is finished. It is what people usually mean by multitasking: the brain is not running two tasks at once, it is alternating between them and paying a cost at every change.
The switch cost
Each switch leaves part of your attention on the task you just left. You reload context, remember where you were, and rebuild the mental model. On demanding work that recovery takes minutes, not seconds, and it repeats every single time. Four switches in an hour can consume more of that hour than the work does.
The cost is also invisible from the inside. Switching feels productive because something is always happening. What actually happens is a day of activity with little finished.
What increases it
- Switches between unrelated contexts cost more than switches within one, so code to code is cheaper than code to a billing query.
- Interrupted work costs more than completed work, because the unfinished task keeps pulling attention back.
- Anything requiring you to hold several things in mind at once is worst affected.
Reducing it
Batch similar work so switches happen between groups instead of between items: all email at two fixed times, all calls in one afternoon. When you are pulled away mid-task, write the one line you need to resume ("next: fix the null check in parseDate"). That note is far cheaper than reconstructing the context later.
