Once you learn a new word or idea, you suddenly start noticing it everywhere, a quirk known as the frequency illusion.

Also nicknamed the Baader-Meinhof phenomenon, the frequency illusion is the sense that something you just learned about, whether it’s a word, a car model, or a piece of trivia, keeps popping up again and again right after you first noticed it. The thing itself isn’t actually appearing more often; what’s changed is your attention.

Two ordinary mental processes combine to create the illusion. Selective attention means your brain, having just tagged something as relevant, is now primed to notice it in places it would have previously ignored, while confirmation bias means each new sighting reinforces the sense that it’s suddenly everywhere. Together they create a convincing but misleading impression of a real increase in frequency, when really it’s just a shift in what your brain has started paying attention to.