The numbers appear on the screen.
Five of them. Then they’re gone.
Three seconds. That’s all you get.
Then a joke shows up — something about a bear with no teeth or a seafood diet — and by the time you’ve read it and smiled (or groaned), the numbers feel like they belonged to someone else.
What were they?
I’ve been thinking about memory lately. Not nostalgia — the actual mechanical function of holding something in your mind long enough to use it.
It feels like it’s gotten softer.
Not dramatically. Just… softer. The way a muscle gets when you stop using it and don’t quite notice until you try to lift something.
There’s a cognitive test called digit span. Psychologists have used it for decades. They read you a sequence of numbers — three, then four, then five, then more — and you repeat them back. The average adult tops out around seven digits. Some people can hold nine. Some start struggling at five.
It’s not about intelligence. It’s about working memory — the mental workspace where you hold information while you’re doing something with it. Reading. Following a conversation. Remembering why you walked into the kitchen.
The distraction is the whole point, by the way. Anyone can repeat five numbers if they stare at them and nothing interrupts. The interesting thing — the real thing — is whether you can hold them while your attention gets pulled somewhere else.
That’s not a game mechanic. That’s Tuesday.
So I built a thing.
It’s called memTrain. It’s a small web app — a few screens, three difficulty levels, ten rounds, eighty-some jokes. You see the digits. The clock counts down. A joke appears. Then you type back what you saw.
That’s it.
I built it with AI as a co-builder — more on that in a moment — and it took an afternoon. Not because I’m a fast developer. Because I’m not, really. Because the AI did most of the lifting, and I did the thinking.
That gap between what you can imagine and what you can build has collapsed in ways I’m still absorbing.
I want to be careful here, because I’m not trying to sell you on becoming a developer. You don’t need to be.
What I’m saying is that the tools available right now let a curious person with a clear idea build something real. Not a mockup. Not a sketch. A working, deployed, shareable thing.
I wanted a memory trainer. I didn’t find one I liked. So I described what I wanted, worked alongside an AI, and two hours later I was playing rounds and losing to my own creation.
There’s something quietly profound about that. Not because of the technology. Because of what it says about what’s still possible — at any age, with any background — when the barrier between idea and thing gets this thin.
I’m approaching seventy.
I think about that sometimes. Not with dread — I’m genuinely curious what this decade is going to be — but with a kind of honest reckoning. Some things are getting harder. The names. The words that used to come quickly. The sequence of events from last Thursday.
I don’t think that’s fixed.
I think it’s a muscle.
And muscles respond to use.
Go try it. One game. Two minutes. Pick the difficulty that sounds right and see where your digit span lands.
Don’t worry about the score. Just notice what it feels like to hold something, get interrupted, and reach back for it.
That reaching — that’s the exercise.
