Why Math-Puzzle Alarms Like Alarmy Stop Working After a Few Weeks

Math-puzzle alarms do get people out of bed, especially in the first few weeks. What they don’t reliably do is keep someone from lying back down thirty seconds later, because solving a puzzle and staying awake are two different behaviors, and the app only enforces one of them.

Alarmy — marketed under the name “Sleep If U Can” by the South Korean studio Delightroom — is the reference implementation of this whole category, so it’s worth taking apart on its own mechanics rather than by reputation. The alarm won’t silence until you clear one of several dismiss tasks: solve an arithmetic problem (with adjustable difficulty, up to multi-step equations), shake the phone a set number of times, scan a barcode on a household object you registered in advance, or take a photo that the app matches against a reference image — the bathroom sink, the kitchen light switch, whatever you picked during setup. Each of these forces a body to move and a brain to compute before the noise stops. That’s the entire trick, and it’s a real one. It’s also a narrower trick than most reviews give it credit for.

What the puzzle actually changes

Behavior design researcher B.J. Fogg, who founded Stanford’s Behavior Design Lab (originally the Persuasive Technology Lab) and built the Fogg Behavior Model, argues that any behavior happens only when three things converge at once: motivation, ability, and a prompt. His shorthand is B=MAP. The alarm is the prompt — that part is solved and has been solved since the first mechanical alarm clock. What separates apps in this category from a stock iPhone alarm is that they manipulate ability, not motivation. Fogg’s own list of factors that make a behavior easier or harder includes six: time, money, physical effort, mental effort (“brain cycles”), social deviance, and routine. Alarmy’s puzzles spend exactly one of those six — mental effort — and spend it hard. A four-digit multiplication problem at 6:10 a.m. burns brain cycles a groggy person doesn’t have spare capacity for, which is precisely why it works as a wake-up jolt.

But burning mental effort at the moment of waking says nothing about the person’s motivation to remain awake afterward. Nothing in the mechanic changes whether staying up is something the user actually wants to do at 6:11, only whether they can silence the noise at 6:10. Those are adjacent problems that get treated as one problem, and the gap between them is where the habit erodes.

Why the puzzle stops working after a few weeks

This is the follow-up question worth answering directly, because it’s the one every one-star review eventually asks in different words: the puzzle doesn’t get easier, so why does it stop working? The honest answer is that the puzzle was never the hard part — computing 47 × 6 while annoyed is trivial for most adult brains even half-asleep, once the specific motor pattern of “wake, grab phone, type numbers” gets rehearsed a few dozen times. What erodes isn’t math ability, it’s the novelty of the interruption. The first week, an unfamiliar task at 6 a.m. is jarring enough to force real alertness. By week four, the same task is a scripted five-second detour on the way back to the pillow. The body has learned to perform the ritual without the mind coming fully online, the same way a person can silence a phone’s normal alarm slider without remembering doing it thirty seconds later.

Photo mode resists this slightly longer, since walking to the bathroom sink involves standing and light exposure, both of which have a stronger physiological wake effect than tapping a keypad. But it converges on the same ceiling eventually: users report a groggy, half-narrated internal monologue — “sink, camera, done, bed” — that gets faster and less conscious with repetition. The friction is real. It just isn’t the kind of friction that compounds. Multiplication tables don’t get harder because your commitment weakened; they get faster because your hands memorized the choreography.

What the app never touches

The deeper limitation is what happens in the sixty seconds after the puzzle clears, and there the app has no opinion at all. Nothing in Alarmy’s design detects whether someone got back into bed after taking the sink photo. Nothing follows up, checks in, or costs the user anything socially if they do. The dismiss mechanic is a closed loop between one person and one phone — solve the problem, alarm goes quiet, story over from the software’s point of view. Compare that to a mechanic built around a social witness: a friend who gets a notification, sees a timestamped photo, and can see (or ask) whether the person actually stayed up. That design touches the “motivation” variable in Fogg’s model directly, because the consequence of going back to sleep now involves another person’s attention rather than just the user’s own willpower against a warm bed. It’s a completely different lever than the one Alarmy pulls, and it’s worth being precise about that rather than pretending one approach is simply a worse version of the other.

Both approaches are legitimate answers to different halves of the same equation. A puzzle-based dismiss is a good fit for someone whose main problem is dismissing alarms in their sleep without registering they did it — sleepwalking through a slider tap, essentially. It does nothing for someone who wakes up fully, understands exactly what they’re doing, and chooses to go back to sleep anyway, because that’s a motivation failure, not an ability failure, and no amount of arithmetic changes what a person wants to do at 6:11 a.m.

If you’re comparing categories rather than single apps, a broader survey of alarm apps and where each one tends to fail covers more of the ability-side tools in the same detail, and puzzle-and-photo apps also show up as one option among several in a testing pass aimed specifically at heavy sleepers, where the tradeoffs between friction-based and witness-based designs come up again from a different angle.

None of this is a knock on the category. A math problem at 6 a.m. is a genuinely clever piece of interaction design, and for plenty of people it’s exactly enough friction to break a specific bad habit. It’s just solving for ability, and ability was rarely the whole problem in the first place.

I write for DontSnooze, which takes the motivation side of Fogg’s equation — a friend sees whether you actually got up — rather than the ability side that puzzle and photo mechanics address. That’s a real design difference, not a ranking of which half of B=MAP matters more.