WoW Brain Blog

Notes on cognitive training, AI coaching, and goal architecture from the WoW Brain team.

• I removed streaks from my cognitive training app. Here's what happened to DAU.

  Every habit app has a streak counter. We killed ours after eight months of user interviews. Retention did not go where we expected.

• I A/B tested 12 morning check-in questions. Only 3 predicted whether users came back.

  Twelve variants of a two-minute morning check-in, six weeks of data, and a surprising finding — most questions users happily answered didn't move retention at

• The 8 cognitive dimensions we track — and why a single 'IQ' score misses everything that matters

  Cognitive Radar measures 8 dimensions weekly instead of one composite score. Here's the reasoning and what each dimension means.

• I built an AI Neuro-Coach on FastAPI — here's what 60 cognitive trainers taught me about attention

  Rebuilding a 20-year clinical protocol as a daily AI-coached app. Lessons on adaptive difficulty, evening rituals, why willpower is the wrong metric.