My Brain Has 46 Tabs Open and None of Them Are Actually Closing

I used to think I was decent at multitasking. I’d be writing something, get a Slack notification, check it, get pulled into a thread, come back to my original task fifteen minutes later, and blame the resulting brain fog on poor sleep or not enough water. Definitely not the water.

Then I read a 2009 paper by a researcher named Sophie Leroy and felt personally targeted.

The paper is called “Why Is It So Hard to Do My Work?” which is the kind of academic title that makes you think someone had a really bad week before sitting down to write it. Leroy is a professor at University of Washington and she coined a term in that paper: attention residue.

The idea is this. When you switch from one task to another, especially if the first task is unfinished or you got interrupted mid-way, part of your attention doesn’t actually switch. It stays behind. You’re physically working on Task B, but a background process in your brain is still running Task A. Your attention left a residue.

This is not a metaphor. It’s a measurable cognitive phenomenon. Leroy’s experiments showed that people who switched tasks mid-stream performed significantly worse on the new task than people who were allowed to finish before switching. The residue from the interrupted task actively degraded their performance on the next thing. And the kicker is, this effect applied regardless of whether the switch was big (moving from one major project to another) or tiny (pausing to quickly check an email).

That “quick check” you told yourself was harmless. It wasn’t.

The brain apparently has a fundamental need for completion. When something is unfinished, it stays active. Not actively active, you won’t be consciously thinking about it, but somewhere in the background it’s running, chewing up cognitive resources you were hoping to use for the thing you’re actually supposed to be doing. It’s like having an app open in the background you forgot about. The screen is showing something else, but your battery is draining.

This is estimated to cost somewhere around 40% of productive time for people who switch contexts frequently. Which is most people in most modern jobs. Which is probably you.

And here’s what made me put my phone down for a moment: it’s gotten worse. Not because we’ve gotten lazier or more distracted, but because the environment we work in now is specifically designed around the assumption that context switching is cheap. Slack, Teams, Gmail, WhatsApp, Discord, browser tabs, AI tools asking follow-up questions, notification badges with little numbers that feel vaguely threatening. Every one of these is an invitation to generate attention residue.

Even AI assistants add to this. The more tools you’re juggling, the more cognitive transitions you make, the more residue accumulates. By 11am on a typical workday, you might be running five or six background processes from tasks you’ve touched and abandoned, all quietly degrading everything you’re trying to focus on.

The solution Leroy and her co-researcher Theresa Glomb came up with is almost offensively simple. They call it the “Ready to Resume Plan.” When you get interrupted, or when you have to switch tasks before finishing something, take sixty seconds to write down where you were and what you were planning to do next. That’s it. Just write it down.

The act of externalizing your progress gives your brain permission to let go. It essentially tells the background process: “saved, you can close now.” The cognitive residue clears, because your brain no longer needs to hold on to the state of the unfinished task. It’s been captured somewhere outside your head.

I started doing this and it felt slightly ridiculous for the first week and then I noticed I was actually finishing things.

There’s something here that applies to how we build systems too, not just how we work in them. Every handoff between services, every context switch in an agent pipeline, every interruption in an agentic loop has a cost. The residue is real at the human level and at the systems level. The best architectures, and the best work habits, minimize how often that cost is paid.

Anyway, I should go close some of those tabs. BRB.