Attention residue, and the 30-second note that reduces it

The short version

When you switch away from a task you have not finished, part of your attention stays behind. Sophie Leroy called this attention residue, and showed that it hurts performance on whatever you switch to. Later work with Theresa Glomb found a cheap remedy: before switching, take under a minute to note where you are and how you will pick the task back up.

What the researchers did

Leroy (2009), published in Organizational Behavior and Human Decision Processes, used laboratory experiments in which participants worked on a first task and then moved to a second. The design varied whether people had finished the first task and the conditions under which they stopped, then measured how much the first task was still on their minds and how well they performed on the next one.

Leroy and Glomb (2018), published in Organization Science, looked at interruptions. Participants started a task, were interrupted, and had to work on an unrelated task. Some were told they would have plenty of time when they returned to the original task; others were told they would be under time pressure. Across four studies — including a field study and a laboratory study of the remedy — some participants first made a brief "ready-to-resume" plan: writing down where they were, what they would do next, and any open issues.

What they found

• People find it hard to move their attention away from an unfinished task, and their performance on the next task suffers.
• In the 2009 work, finishing the first task under time pressure appeared to give people a stronger sense of closure, making it easier to move on.
• In the 2018 work, people who expected time pressure when returning to an interrupted task showed more attention residue and did worse on the interrupting task — processing information less carefully and missing errors.
• The ready-to-resume plan reduced attention residue, so performance on the interrupting task no longer suffered.

Limits and caveats

Most of this evidence comes from controlled experiments with relatively short, artificial tasks, and published summaries do not give large-sample effect sizes. Attention residue is measured indirectly. The remedy has been tested in a handful of studies by the same research team rather than replicated widely.

What it means for how you work

Fewer switches is the first line of defense. When you must switch — a meeting, an urgent request, the end of the day — spend 30 seconds writing a "where I left off" note: the current state, the next step, and anything unresolved. It costs almost nothing and is one of the more practical findings in focus research. If you track time by project, the moment you stop one timer and start another is a natural cue to write that note. The same mechanism shows up in research on planning for unfinished goals (Masicampo & Baumeister, 2011).