The meeting was with the chief executive of the company Sophie Leroy worked for, and it mattered. She was a consultant then, running more and more projects at once and switching between them all day. By her own account, she usually found it easy to focus.
At the end of the meeting, she turned to her team. They had forgotten to ask one question, she told them.
“They looked at me funny and said, ‘No, we did, we asked it,’” she recalled years later, in a 2024 profile by her university. “I realized then that my brain had, for a few minutes, been thinking about another project entirely.”
The evidence was on the table. “You could see on my notepad that I had written a little to-do list with items from my other projects,” she said, “and that my brain kept going to those in parallel to the current meeting.”
Leroy went on to spend some 20 years studying interruptions. It wasn’t an easy sell. She still recalls the first review she got on a paper about them, in the early 2000s: “Why are you studying this? Who cares about interruptions?”
In 2009 she published two experiments under the title “Why is it so hard to do my work?” and gave the problem a name: attention residue, thoughts about one task that stay with you after you move to the next. People found it hard to pull their attention away from a task they hadn’t finished, she reported, and they did worse on the task that came next.
Finishing the first task wasn’t enough, though. In her results, people let go of a finished task when they had finished it under time pressure, and that pressure contributed to better performance on the next one.
Nine years later, with Theresa Glomb of the University of Minnesota, she turned to interruptions. Participants were pulled off a task and told either that they would have plenty of time to finish it later or that they wouldn’t. Those expecting a squeeze carried more residue into the interrupting task. They processed information less carefully, missed errors and were less likely to find the best answer to a decision problem.
Then the pair tested a fix they called a “ready-to-resume” plan. Before switching, you note where you were and what you planned to do next. Less than a minute, Leroy said, may be enough. In a field study and a lab study, people who made the plan switched their attention more fully and did better on the interrupting task.
Leroy is now a professor at the University of Washington Bothell, which she joined in 2014. Her notepad in that meeting held a to-do list for the other projects, written during the meeting. The plan she later tested is a list like that, written on purpose, before the switch instead of during it.