Fluid vs Crystallized Intelligence
Two kinds of smart, two different aging curves
Your brain houses two fundamentally different types of intelligence, and they age on completely opposite curves. Fluid intelligence, your ability to reason through novel problems and think on your feet, peaks in your 20s and gradually declines. Crystallized intelligence, your accumulated knowledge and vocabulary, keeps rising well into your 70s.
This is why a 60-year-old can struggle to learn a new app interface but easily explain a complex concept they've worked with for decades. It's also why most cognitive demands in real life are a mix: a lawyer trying a case is using fluid intelligence to react in the moment and crystallized intelligence to draw on years of legal precedent. Both forms matter at every age. Just in different ratios.
Related Science Card
Keep training to unlock
Fluid vs Crystallized