A 10-question quiz on the most-repeated habit, productivity, and wellness myths. Each answer comes with the named study or meta-analysis that disproves it.
Ten claims you've probably heard — from "21 days to form a habit" to "10,000 hours to mastery." For each one, you choose True or False. Every answer comes with the named study or meta-analysis that settles it.
Tip: keyboard works too — T for true, F for false, Space to advance.
Most productivity and habit advice you've heard comes from one of two places: a single influential book that simplified an academic finding for general readers, or a viral article that repeated the simplification without checking the source. Once a number enters popular culture — 21 days, 10,000 hours, 10 percent of the brain — it survives long after the underlying claim has been corrected or disproved, because the number is more memorable than the correction.
Behavioral science also has a replication problem. Many influential results from the 1990s and 2000s — including ego depletion, power posing, and several mood-priming effects — have not held up in pre-registered multi-lab replication attempts. That doesn't mean the original researchers were wrong on purpose; it means the original studies were often small, under-powered, and selected for surprising results. The careful version of habit science today (Wendy Wood, Phillippa Lally, Andrew Huberman's lab summaries) looks different from the bestseller version.
Three signals had to be present for an item to make the list:
Single studies — even big ones — don't make a claim "true" or "false" for the quiz. We required either a replication-driven consensus or an authoritative review.
The point of busting myths isn't to make you cynical about every habit tip. The point is that the real numbers are usually more forgiving than the myths. The actual Lally finding — median 66 days, range 18 to 254 — is more permissive than "21 days or you've failed." Macnamara's 26% effect of deliberate practice is more permissive than "10,000 hours or you'll never be a master." Working with your biological chronotype is more permissive than "wake up at 5 a.m. like all successful people."
Once you replace the myths with the real numbers, building a sustainable habit gets easier — not harder. That's the editorial premise behind every guide on this site.
Each item in the quiz is a claim that's popular in productivity, self-help, or wellness content but doesn't hold up against the actual research. We focused on claims that have either failed replication (like ego depletion), have a clearer better-evidenced replacement (like the Lally 2010 finding vs. the '21-day rule'), or have no peer-reviewed basis at all (like the 10%-of-the-brain claim).
Most of these stuck because they're catchy, simple, and were repeated in a best-selling book or popular article before the original study had been replicated. Once a number — '21 days', '10,000 hours', '10 percent' — enters self-help culture, it's hard to dislodge. The point of the quiz isn't to embarrass anyone; it's to make replacing the wrong number with the right one easier.
No — these are 10 of the most-repeated. Others worth knowing: stretching prevents injury (mostly false per Cochrane reviews), breakfast is the most important meal (no causal evidence), standing desks burn meaningful calories (~9 cal/hr difference vs. sitting), cold showers boost immunity (mixed evidence). We may add a 'Round 2' quiz if there's interest.
We anchor on three signals: a major pre-registered multi-lab replication failing (like Hagger 2016 for ego depletion), a meta-analysis correcting for publication bias finding no effect (like Pietschnig 2010 for the Mozart Effect), or a consensus statement from a clinical-authority source (like Harvard Health on the 8x8 water rule). Single studies — even big ones — don't make a claim 'true' or 'false' for our purposes.
Each item's explanation links directly to the named source — the original study, meta-analysis, or authoritative review. Start there. For habits specifically, the Lally 2010 paper and Wendy Wood's lab work (especially her 2019 book 'Good Habits, Bad Habits') are the foundational behavioral-science reading.
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