Glossary
What is Context Switching?
Short answer
Context switching is the mental cost of moving attention between tasks. Unlike CPU context switches (microseconds), human context switches cost 10–25 minutes of lost focus per switch.
Full definition
The cost isn't the switch itself — it's the 're-priming' of working memory. Every task swap flushes a chunk of relevant state (where you were, what you intended). Heavy switchers regularly finish the day unable to name what they accomplished. IdleMac reduces silent switching by making the moment you stop engaging audible — which often reveals how often it happens.
A 2005 UC Irvine study found the average knowledge worker is interrupted every 11 minutes and takes 23 minutes to return to the original task.
Examples
- Alt-tabbing from code to Twitter to Slack to code.
- Checking email between every small task.
- Reading a doc, opening a tab, forgetting the doc.