Open loops: why your brain won't shut up (and how to close them)

That background hum of things you haven't done? It's not anxiety. It's your brain's accounting system.

You know the feeling. You're trying to focus on something important and there's a low-level noise in the back of your mind. Not about anything specific. Just a general sense that you've forgotten something, or that there's something you should be doing, or that the thing you're working on right now isn't the thing you should be working on.

It's there when you wake up. It's there when you try to relax. It's there at 11pm when you're supposed to be falling asleep. A background hum that never quite resolves, made up of dozens of half-remembered commitments all demanding attention simultaneously.

That isn't anxiety, or not only anxiety. It's your brain doing exactly what it's designed to do.

The open loop

Every commitment you've made to yourself but haven't completed or captured externally is what David Allen calls an "open loop." The term is borrowed from engineering: in a control system, an open loop is a process that's been initiated but hasn't received the feedback needed to close it. It stays active, consuming resources, until it's resolved.

Your brain works the same way. Every "I should really..." and "I need to remember to..." and "I'll get to that eventually" is an open loop. And your subconscious tracks every single one, 24 hours a day, with no sense of proportion. It doesn't know that "clean the gutters" is less important than "figure out my career direction." It doesn't know that "reply to Sarah's email" can wait until Monday. Everything is present tense in there. Everything is happening now, or rather, everything is not happening now, and that's the problem.

Most people are carrying somewhere between 50 and 100 open loops at any given time. Some of them are big (career, relationships, finances). Most of them are small (that lightbulb that needs replacing, that article you meant to read, that form you need to fill out). Individually each one is trivial. Collectively they're a constant drain on your mental resources, and that drain is the background hum you can't switch off.

The Zeigarnik effect

This isn't just a metaphor. In 1927, a Soviet psychologist named Bluma Zeigarnik ran a series of experiments showing that people remember unfinished tasks significantly better than completed ones. Waiters, for example, could recall the details of open orders with remarkable accuracy but forgot them almost immediately after the bill was paid. The task, once complete, released its grip on working memory.

The implication is striking: your brain allocates cognitive resources to unfinished business and holds them there until the loop is closed. Each open loop is a background process running in your mental operating system, consuming a small but real portion of your working memory. One or two loops are manageable. Fifty are not. At fifty, you're trying to run your life on a processor that's already at capacity before you've started your actual work.

Sophie Leroy's research on attention residue, published in 2009, extended this further. She found that when people switch from one task to another, part of their cognitive processing stays behind on the previous task. The effect is strongest when the previous task was unfinished. Your brain, as Leroy puts it, has a fundamental need for completion, and when that need is unmet, it holds on to the incomplete work even when switching focus is necessary.

This is why you can be sitting in a meeting thinking about the email you didn't send this morning. It's not that you lack discipline or focus. Your brain is running a background process on that email, and it won't release those resources until the loop is closed.

You don't have to finish it. You have to capture it.

Here's where the research gets genuinely useful. Baumeister and Masicampo's 2011 study found something that surprised a lot of people: you don't actually have to complete a task to get the cognitive relief. You just have to make a concrete plan for completing it and record that plan somewhere you trust.

The moment you write down "email Sarah on Monday morning about the project timeline" in a system you believe will remind you, your brain lets go. The background process shuts down. The loop closes, not because the task is done, but because your brain trusts that it won't be forgotten.

This is the entire scientific basis for why productivity systems work at all. It's not about being organised for the sake of it. It's about giving your brain permission to release the loop. The to-do list, the calendar reminder, the captured note, these aren't just organisational tools. They're loop-closing mechanisms that free up working memory for the thing you're actually trying to do right now.

But there's a critical condition: you have to trust the system. If you write something down in a notebook you never check, your brain knows. The loop stays open. If you save an article to a read-it-later app you never open, your brain knows. The loop stays open. Trust isn't about the tool's capabilities. It's about your honest belief that the thing you captured will surface again when you need it.

The three ways to close a loop

For any open loop, you have exactly three options:

Do it. If it takes less than a couple of minutes, just handle it now. The overhead of capturing and tracking it exceeds the cost of doing it. This is Allen's two-minute rule, and it's one of the fastest ways to close a batch of loops in a single sitting.

Capture it. If you can't do it now, get it out of your head and into a system you trust. Not a vague intention to do it later. A specific next action, in a specific place, that you will actually see again. The specificity matters: "sort out the insurance thing" doesn't close the loop because your brain knows that's not a real plan. "Call insurance company on Tuesday, ask about policy renewal" does.

Drop it. Some loops should be closed by consciously deciding you're not going to do them. That book you've been meaning to read for two years? Maybe you're just not going to read it. That project idea that felt exciting six months ago? Maybe it's dead. Acknowledging this and removing it from your mental inventory is a legitimate way to close the loop. It's not failure. It's editing.

Most people do none of these three things for most of their open loops. They just carry them, indefinitely, and wonder why they're always tired.

Different flavours of stuck

Not all open loops feel the same. Fernando Borretti's taxonomy of three types of procrastination maps neatly onto different kinds of loops:

Some loops stay open because of attention. You want to close them but your brain keeps sliding off the task. These respond to systems, timers, and medication.

Some loops stay open because of emotion. You know what to do but the task triggers anxiety or dread, so you avoid it. These respond to doing it scared, doing it in a safe environment, or getting someone to sit with you while you do it.

Some loops stay open because of uncertainty. You don't know what the right move is, so you ruminate instead of acting. These respond to writing the problem out, talking to people, or using an AI thinking partner to externalise the swirling thoughts.

The type of loop determines the type of solution. Applying the wrong fix (a timer for an emotional block, willpower for a decision problem) leaves the loop open and adds frustration on top.

The trust problem

Most productivity systems fail not because they're poorly designed but because the person stops trusting them. And trust erodes fast.

You capture something in a note-taking app, and three weeks later you can't find it. Loop reopened. Your brain learns: that system loses things. So next time, instead of capturing the thought and letting go, you capture it and keep worrying about it. The background process stays running because the external system didn't earn a full release.

This is why findability matters as much as capture. A system that lets you dump things in but can't reliably get them back is worse than no system at all, because it gives you the illusion of having closed the loop while your brain knows better.

It's also why keeping your active projects visible matters so much, particularly if you have ADHD. Borretti's principle of "out of sight, out of mind" cuts both ways: if your projects aren't visible, they slip out of conscious awareness, but your subconscious keeps tracking them. The loop stays open even though you've forgotten what's in it. You feel the hum without knowing the source.

A workspace that surfaces your projects, your tasks, your recent captures without you having to go looking for them is doing loop-closure work in the background. Every time you glance at your active projects and see that nothing has been forgotten, your brain relaxes a fraction. The hum gets quieter.

The quiet mind

Allen describes the ideal state as "mind like water," a borrowed martial arts concept where the mind responds proportionally to whatever arrives and then returns to calm. No residue, no background hum, no open loops consuming resources.

It sounds idealistic, and maybe it is as a permanent state. But most people have experienced moments of it. That feeling after you've finished a big project and cleared your inbox and there's genuinely nothing pending. The clarity, the lightness, the sense that you could think about anything because nothing is demanding your attention.

That state isn't magic. It's just what happens when most of your loops are closed. And you don't need to close all of them to feel the difference. Even closing ten or twenty, in a single focused session of capturing and deciding, produces a noticeable shift.

The goal isn't perfection. The goal is to carry fewer open loops so that more of your brain is available for the things that matter.

Every commitment you capture is a loop closed. Every decision you make is a loop closed. Every project you consciously drop is a loop closed.

The hum gets quieter with each one.

Inspired by David Allen's Getting Things Done.