Attention residue is leftover attention that stays attached to a previous task after you switch, and it measurably lowers performance on the next one. Sophie Leroy’s 2009 experiments found the residue is worse when the first task is unfinished, and that finishing it is not enough on its own to fully disengage.
Key takeaways
- Attention residue is leftover working memory stuck on Task A after Task B has started, and it impairs performance on B (Leroy, 2009).
- Leaving Task A unfinished makes the residue worse; completing Task A without a real push to disengage is still not enough on its own (Leroy, 2009).
- A brief ready-to-resume plan reduced residue and protected interrupting-task performance across four studies (Leroy & Glomb, 2018).
- Task-switching cost is different: it is the time spent reloading rules, not the lingering thoughts that follow you in (Rubinstein, Meyer & Evans, 2001; Monsell, 2003).
- Interrupted office workers speed up to compensate and report more stress, effort and time pressure (Mark, Gudith & Klocke, 2008).
What is attention residue?
Attention residue is the leftover attention that stays attached to a previous task after you have already switched, and it shows up as worse performance on whatever you do next. Sophie Leroy coined the term in 2009. It is not “distraction” in general: thoughts about Task A keep running after Task B has started, and they take capacity Task B needed. Cal Newport’s Deep Work is where most knowledge workers met the slogan version — “your brain is still in the last tab.” The research is narrower. Residue is not a personality trait, and it is not the same thing as being bad at focusing. It is what happens at the join between two tasks, especially when the first one is still open.
How is attention residue different from a switch cost — or from the Zeigarnik effect?
Switch cost is the time it takes to reload a new set of rules; residue is the previous task still occupying working memory after that reload has begun. Rubinstein, Meyer and Evans (2001) measured the time tax of alternating between two rule-based tasks. Monsell’s (2003) review splits that tax into reconfiguring the new task set and leftover activation of the old one. Residue is closer to the second half, but it is scored as performance on the next task, not as milliseconds on a trial.
| Construct | What it names | What it does not name |
|---|---|---|
| Attention residue (Leroy, 2009) | Thoughts about Task A that persist after Task B has started, impairing B | The clock time of the switch itself |
| Switch cost (Rubinstein, Meyer & Evans, 2001) | Extra time to reconfigure from one task’s rules to another’s | Whether the previous task is still being mentally rehearsed |
| Zeigarnik-style unfinished memory | Unfinished tasks stay more accessible in memory than finished ones | A measured drop in the next task’s performance |
Why does the last task still run after you switch?
The mind treats an unfinished task as an open loop, and an open loop keeps requesting attention even after you have sat down in front of something else. In Leroy’s 2009 experiments, residue was worse when people left Task A incomplete. Finishing A helped only with a real push to disengage; completion without that pressure did not fully release working memory. That is the finding most “just wrap it up” advice overstates.
Leroy and Theresa Glomb’s 2018 follow-up, across four studies, found that expecting to resume under time pressure made it harder to give the interrupting task full attention. A short ready-to-resume plan reduced that residue. The move is close to an implementation intention: name the cue for coming back so the current task does not have to hold the whole plan.
Why does attention residue cost more than it feels like?
The cost rarely shows up as one dramatic failure — it shows up as a next hour that took more effort than the work justified. Mark, Gudith and Klocke’s 2008 field study found interrupted office workers did not simply keep the same pace and finish later. They worked faster to catch up, and reported more stress, effort and time pressure than people who worked without interruption. Task batching cuts how many times you pay a switch; residue is what you pay after a switch that left something hanging.
One honest caveat. Leroy’s experiments used laboratory tasks, not a day of Slack. The 2018 ready-to-resume studies test a brief planning intervention, not a promise that parking a note will save a fixed number of minutes. Treat residue as a well-supported mechanism. Do not treat it as a stopwatch.
How do you clear attention residue?
Either finish the first task for real, or park it so completely that working memory can let go — “I’ll come back to it” is not parking. In our experience the reliable version is a written next action, not a mental bookmark. David Allen’s Getting Things Done made that move famous as capturing an open loop; Leroy and Glomb’s ready-to-resume plan is the laboratory cousin.
- Finish it if it is genuinely short. The two-minute rule is the right tool when closing Task A would take less time than writing a resume note.
- If you cannot finish, write a ready-to-resume note. Two lines: where you stopped, and the next physical action. That is the 2018 intervention.
- Switch once, not in a chain. Residue stacks. A planned hand-off inside a time-blocked hour is cheaper than five “quick” detours.
- Protect the next block. A sealed window stops the parked task walking back in. A weekly review is where leftover loops get collected so they are not still running on Monday.
What are the common mistakes?
The usual failures are mislabelling, fake finishes, and parking the loop only in your head.
- Calling every distraction “attention residue.” Residue is leftover attention from a previous task. A new ping is an interruption; chasing a new idea mid-block is the shiny-object tax.
- Assuming finishing the first task is enough. Leroy (2009) found completion without a push to disengage did not fully clear the residue.
- Parking in your head. “I’ll remember where I was” keeps the loop loaded. Write the next action down.
- Chaining unfinished switches. Five unnamed open loops are five residues, not one.
- Using willpower as the clearing method. Trying to “be present” on Task B while Task A is still unnamed is the expensive version of the 2018 finding. The cheaper version is the note.
- Treating residue as a diagnosis. Persistent, cross-context trouble starting or switching is a reason to talk to a clinician. This article is not medical advice.
When is parking not enough?
A ready-to-resume note assumes you can pause for thirty seconds and that the next task can actually have you — neither is true in every role. Support and on-call work is interrupted by design; the note still beats a blank switch, but it will not invent a sealed hour the job does not permit. Parking also fails when the real problem is starting at all. An unnamed hard task you keep “just checking” is closer to procrastination than to residue.
What does the evidence actually show?
The most reliable finding is that an unfinished or time-pressured-return switch leaves measurable residue on the next task — not a universal minutes-lost figure for every messy afternoon.
| Study | Design & focus | Finding | What we used it for |
|---|---|---|---|
| Leroy (2009) | Lab experiments switching from Task A to Task B | Unfinished A left residue that impaired B; completion without a push to disengage was not enough on its own | Names the construct and the unfinished-task aggravator |
| Leroy & Glomb (2018) | Four studies of interruptions plus a ready-to-resume intervention | Anticipating a time-pressured return raised residue on the interrupting task; a brief resume plan reduced it | The practical park: write the return before you leave |
| Rubinstein, Meyer & Evans (2001) | Lab task-switching with simple, well-practiced rules | Every switch cost measurable time, growing with rule complexity | Separates switch time from leftover attention |
| Mark, Gudith & Klocke (2008) | Field study of interrupted vs. uninterrupted office work | Interrupted workers compensated by working faster, with more stress and effort | The cost shows up as pace and mood, not only as a foggy next task |
Monsell’s 2003 review is the map these experiments sit on — reconfiguration plus leftover activation of the previous task set — not a fifth trial with its own effect size.
Frequently asked questions
What is attention residue in simple terms?
Attention residue is leftover attention from a previous task still running after you start the next one. Sophie Leroy’s 2009 experiments found that leftover attention lowers performance on the new task, especially when the first task was left unfinished. It is not a synonym for “distracted,” and it is not the clock time of the switch itself — it is the hangover that follows the switch.
Is attention residue the same as the Zeigarnik effect?
No. The Zeigarnik finding is about memory: unfinished tasks tend to stay more accessible than finished ones. Attention residue is about performance on the next task — thoughts about Task A still occupying working memory after Task B has started. They are related as open loops, but citing Zeigarnik as if it measured a drop in Task B quality overstates that older work.
How do you get rid of attention residue?
Either finish the first task for real, or park it with a ready-to-resume note: where you stopped, and the next physical action. Leroy and Glomb (2018) found that brief reflection-and-plan before handling an interruption reduced residue and protected performance on the interrupting work. A mental “I’ll come back to it” keeps the loop loaded. Writing the return is what lets the current task have you.
Does finishing a task always clear attention residue?
No. Leroy (2009) found that completing Task A helped only when it came with a real push to disengage. Finishing the file without that closure — or “finishing” by skimming the last step so you can claim it is done — is not the same as releasing working memory. If you cannot finish, the more reliable move is the written resume note, not a fake close.
Is attention residue a sign of ADHD?
Not by itself. Residue is a normal cost of leaving a task open and switching under load; Leroy studied it in ordinary experimental samples, not as a diagnostic marker. Persistent, cross-context difficulty starting, switching or sustaining attention is a different question, and it is a reason to talk to a clinician rather than to collect another productivity label. This article is not medical advice and does not diagnose ADHD.
Is attention residue the same as a task-switching cost?
They sit next to each other and get conflated. A switch cost is the extra time required to reload a new set of rules (Rubinstein, Meyer and Evans, 2001). Attention residue is leftover thought about the previous task that then impairs the next one (Leroy, 2009). You can pay a switch cost with little residue if the first task is cleanly parked.
Related reading on The Growth Reads
The books behind this
- Deep Work summary & review — protecting a block so the last tab does not keep running
- Getting Things Done summary & review — capturing the open loop so working memory can drop it
- Hyperfocus summary & review — attention as a scarce resource
- Indistractable summary & review — switches that are chosen, not leaked
Related articles
- How to focus better — the A2 anchor this spoke sits under
- Task batching — fewer switches, so fewer residues
- Implementation intentions — the if-then cousin of a ready-to-resume plan
- Time blocking — the calendar slot a clean switch needs
- The two-minute rule — when finishing is cheaper than parking
Go deeper
How this article was researched
The Growth Reads editorial team writes from primary sources: the books themselves and the peer-reviewed literature behind the claims. Findings above were checked against Crossref records and published abstracts, and are quoted with study design rather than as a stopwatch. No cited study measures a universal “minutes of residue per interruption” for a normal knowledge-work day.
This article contains no medical advice. Attention residue is a task-switching mechanism, not a diagnosis.
How we work: every article on The Growth Reads is built from the books in our library plus the research they rest on. Read our full methodology.
Sources
- Leroy, S. (2009). Why is it so hard to do my work? The challenge of attention residue when switching between work tasks. Organizational Behavior and Human Decision Processes, 109(2), 168–181. doi:10.1016/j.obhdp.2009.04.002
- Leroy, S., & Glomb, T. M. (2018). Tasks interrupted: How anticipating time pressure on resumption of an interrupted task causes attention residue and low performance on interrupting tasks and how a “ready-to-resume” plan mitigates the effects. Organization Science, 29(3), 380–397. doi:10.1287/orsc.2017.1184
- Rubinstein, J. S., Meyer, D. E., & Evans, J. E. (2001). Executive control of cognitive processes in task switching. Journal of Experimental Psychology: Human Perception and Performance, 27(4), 763–797. doi:10.1037/0096-1523.27.4.763
- Monsell, S. (2003). Task switching. Trends in Cognitive Sciences, 7(3), 134–140. doi:10.1016/s1364-6613(03)00028-7
- Mark, G., Gudith, D., & Klocke, U. (2008). The cost of interrupted work: More speed and stress. Proceedings of the SIGCHI Conference on Human Factors in Computing Systems (CHI ’08), 107–110. doi:10.1145/1357054.1357072