HomeResearch
What the evidence actually says
Published research finds that a phone within reach costs you attention even when you never touch it — face-down, switched off, still expensive. That finding is why Spark is a separate object you leave behind rather than one more blocker living on the phone.
None of it is ours. These are independent, peer-reviewed studies by other people, published in journals and conference proceedings you can read for yourself. We have not run a study, commissioned a survey or measured a single Spark user — so there is no figure on this page that we are the source of, and every claim below is followed to its author.
Four studies, all of them somebody else’s
Each card states the finding in the authors’ own terms and links the paper. If a card and the paper disagree, the paper is right and the card is a bug.
Observational study of information workers found it took an average of 23 minutes 15 seconds to return to an interrupted task, usually after two intervening detours.
Mark, Gudith & Klocke — “The Cost of Interrupted Work” (CHI 2008) (opens the original study)Participants who left their phone in a different room performed measurably better on working-memory and fluid-intelligence tasks than those whose phone sat on the desk — even when it was powered off. Proximity alone consumed attention.
Ward, Duke, Gneezy & Bos — “Brain Drain” (Journal of the Association for Consumer Research, 2017) (opens the original study)Pairs of strangers who talked with a phone in view reported lower relationship quality, less closeness and less trust than pairs who talked with no phone present. Nobody had to touch it.
Przybylski & Weinstein — Journal of Social and Personal Relationships (2013) (opens the original study)Reading on a light-emitting device before bed suppressed melatonin, pushed the circadian clock later, delayed sleep onset and reduced next-morning alertness compared with print.
Chang, Aeschbach, Duffy & Czeisler — PNAS (2015) (opens the original study)“In another room” is not a figure of speech
The Brain Drain study is the reason Spark is a separate object rather than a better-designed app. Participants did not have to use their phone for it to cost them — merely having it on the desk, face-down and powered off, measurably reduced available working memory. Moving it to another room was what changed the result.
A blocker that lives on the phone cannot reproduce that, because the phone is still right there. Distance is doing work that software cannot do. Spark’s design follows directly from it: locking is one free tap and needs nothing nearby, and unlocking needs the key in the room — so the key is the thing you walk away from. How that works in practice.
What this evidence does not say
Cited research is easy to over-read. These are the specific things the four papers above do not establish.
- None of them tested Spark. Nobody has. They describe the problem Spark is aimed at; they are not evidence that our answer to it works.
- The 23-minute figure came from observing people at work, not from an experiment. It is an average of what those researchers watched happen, not a law of attention, and it is not a prediction about your afternoon.
- These are modest samples under specific conditions. An effect that shows up reliably across a group is not a promise about any one person on any one day, and none of these studies followed anyone for months.
- Nothing here measures a phone-free habit over time. They measure what a nearby phone costs in the moment. Whether that cost compounds, and by how much, is not something we can source.
The row we cannot fill in
Sample figure, self-reported by an internal pilot group of 12 — not a published study.
Getting the most out of it
Usage advice, not outcome claims — none of these says how much time anyone saved, because we do not know. The app is free and the key is a one-time purchase, so the only thing you are spending here is attention on where you put it. See what comes in the box.
Put the key where the friction is useful
Not the next desk — the next room. Far enough that fetching it is a decision, close enough that a genuine emergency is never a crisis.
Lock before you need to, not after
The moment to lock is when you sit down, not when you notice you have already lost twenty minutes.
Start with three apps, not thirty
A mode you actually use beats an exhaustive one you abandon. Add the rest once the habit holds.
Pair it with something you already do
Lock when the kettle goes on. Lock when you sit down to eat. Attach it to a trigger that already exists.
Where the argument goes next
Why a physical key
The case for putting the unlock outside the phone, and the honest reasons you might not want to.
Read the caseMechanicsHow Spark works
Modes, the one-tap lock, the challenge–response unlock, and what each operating system actually permits.
See the loopBackgroundWhy we built it
The kitchen drawer that worked better than every app we tried, and what we changed to keep it.
Read the storyDistance you don’t have to maintain.
The research says a nearby phone costs you something whether or not you pick it up. Spark makes that distance a decision you make once, in the morning, instead of one you have to keep winning all day.