You can’t really “train” your brain. Here’s what you can do instead.

This is work is less about taking your brain to a mental gym and more about cultivating the strange and wondrous garden that is your mind. | Getty Images

A lot of people are looking for ways to improve, preserve, and prolong their brain’s health. Just look at the seemingly endless amount of self-help books, podcasts, phone apps, TikToks, and Instagram Reels dedicated to the subject.

And, frankly, it makes sense. Alzheimer’s disease and dementia — conditions that fundamentally involve...