Heuristic
Treat a rule switch as a setup cost
The visible click is not the whole switch; the task rules have to become active again too.
When it fits
- Two tasks both look short, but they use different rules, tools, schemas or definitions and you are deciding whether to interleave them.
When to avoid it
- The cited study is laboratory research and does not quantify a universal real-world switching penalty. Some jobs require rapid switching; the goal is to expose the cost, not forbid it.
Why it matters
When work uses different mental rule sets, count the switch as real setup. Laboratory task-switching studies show measurable switching-time costs, especially as rule complexity rises. Use that evidence as a design cue, not a stopwatch claim: group work that shares the same rules when practical, and leave explicit cues when a switch is unavoidable.
An example
Reviewing ten records with the same validation logic may be a coherent batch. Alternating each record with a different incident-analysis method is a rule switch even if both happen in Excel.
Check your result
The batch boundary follows shared cognitive setup, not convenience alone, and necessary switches have a visible restart cue.
Keep this limit in mind
- The cited study is laboratory research and does not quantify a universal real-world switching penalty. Some jobs require rapid switching; the goal is to expose the cost, not forbid it.
Evidence and sources
Controlled task-switching experiments found switching-time costs when people alternated between task rules, with larger costs for more complex rules and smaller costs when task cues were available.
The experiments do not supply a universal number of minutes lost to every workplace interruption or justify eliminating all switching.
Executive control of cognitive processes in task switching · Abstract