Why your focus timer should not be on your phone

Almost every focus app is a phone app. The Pomodoro timers, the forests that grow while you do not touch the screen, the blockers that lock you out of Instagram: they all have one thing in common. To use them, the phone has to be on the desk, in your hand, or within reach. That is the problem they claim to solve.

The study everyone should read once

In 2017 Adrian Ward and colleagues at the University of Texas ran two experiments with close to 800 participants. People sat a test of working memory capacity and a test of fluid intelligence. Before starting, they were asked to put their phone either face down on the desk, in a pocket or bag, or in another room. Phones were silenced in every condition.

The other-room group did best. The on-desk group did worst. The pocket group sat in between. The effect held for people who said they were not thinking about their phone, and it was strongest in the people who reported depending on it most. Turning the phone fully off did not remove the effect.

The authors' explanation is that not attending to a phone that is present takes effort, and that effort is drawn from the same limited pool the task needs. You do not have to look at the phone for it to cost you. It only has to be there.

One study is one study. A 2022 direct replication (Ruiz Pardo & Minda) did not find the same size of effect, and a 2023 meta-analysis of 22 studies on phone presence found a small but statistically significant cost, strongest for memory. The honest reading is that the effect is real and modest, and that it is one of several: receiving a notification, even unanswered, measurably impairs attention too. Nobody has found that a phone on the desk helps.

What that means for focus apps

A focus app that lives on the phone starts every session by putting the single most distracting object you own where the study says it does the most damage. Blockers make this worse, not better: they turn the phone into something to negotiate with. Each "are you sure?" screen is a check-in with the device you were meant to be ignoring.

There is a second effect. Stothart, Mitchum and Yehnert (2015) showed that merely receiving a notification, without answering it, impairs performance on an attention task at a level comparable to actively using the phone. A timer that runs on the device that also delivers notifications has to fight its own host.

A protocol that takes the study seriously

1. Phone in another room. Not face down, not in a drawer. Another room. If that feels extreme, note that this is the exact condition that produced the best scores.
2. The timer lives on the laptop. The work is there anyway. A browser tab that shows the countdown in its title is enough; you do not need an app.
3. One line before you start. Write what the block is for. It stops the first three minutes being spent deciding.
4. A chime and a desktop notification at the end, so you can leave the tab and trust that you will be told. Without this, people keep checking the timer, which is the phone problem in a new costume.
5. Break away from the screen. Five minutes. The phone stays where it is.

The timer above is built around this protocol. It only runs on a desktop browser, on purpose, and it does not have a phone version and will not get one.

"But I need my phone for work"

Then put it in the other room for twenty-five minutes at a time. The study is not an argument against phones. It is a measurement of what one costs while it sits next to you, and the cost is paid whether or not you use it. Twenty-five minutes without it, four times a day, is a small experiment with a large potential return, and it is free to run.