I should have patented the idea. Next month, Nintendo is releasing Brain Age, a DS game based on the research of the Japanese neuroscientist Ryuta Kawashima. Kawashima found that if you measured the brain activity of someone who was concentrating on a single, complex task — like studying quantum theory — several parts of that person’s brain would light up. But if you asked them to answer a rapid-fire slew of tiny, simple problems — like basic math questions — her or his brain would light up everywhere.

Hence the design of Brain Age. It offers you nine different tests, some of which seem incredibly basic — like answering flash-card math questions — and others which are fiendishly tricky. At one point, the DS shows flashes a grid of numbers for one second, then hides the digits; you have to try to remember where they were located in the grid, in ascending order. After you’ve played a few rounds, the DS calculates your “brain age”: How mentally nimble you are, compared to the statistical averages of other people Kawashima measured. Age 20 is the best you can do — the apex of your mental powers, apparently — and by playing Brain Age every day, you can become mentally younger and younger.

Now, the science here is a little dubious. The idea of a discrete brain age is about as phrenologically suspect as the increasingly-disputed concept of IQ itself. Kawashima believes you improve your cognition by getting your brain to light up all over at once. But not all neuroscientists agree that this full-brain activity means you’re thinking more intelligently.

I’m quibbling, though. The truth is, scientists have long known that you can get smarter and stay smarter by engaging in daily, brain-teasing activity — and Brain Age certainly qualifies.

Indeed, for something that doesn’t even seem like normal “game,” it’s weirdly addictive. The math questions had me so frazzled that I emotionally regressed to about age ten. Brain Age also includes a Stroop test, which flashes the names of colors on screen in mismatched ink — for example, the word “blue” printed in red — and challenges you to name the color of the ink. As any psychologist will tell you, you can keep a lid on things for the first dozen words, but then your brain turns to jelly. My adrenaline was pumping harder than the first time I faced The Flood in Halo.

Plus, when a game actually judges your intellect? Man, that hits home. After my first round, Brain Age claimed I possessed the mind of a 68-year-old, and I nearly wept. I frantically plinked away at math tests for two hours until I got my score down to 33.

I had much the same response to PQ: Practical Intelligence Quotient, another brain-training game released in December. It plays much more like a regular platform-puzzler: You control a little man who inhabits a Tron-like, glowing grid-world composed of cubes. You move cubes into various configurations, which purportedly tests your “planning ability”; meanwhile, you trip a series of switches to open doors, which flexes your logical thinking.

PQ is hard: It plays like the most hellish Tomb Raider level you ever encountered. Indeed, with its spare, geometric shapes, PQ feels like the ur-game that lurks inside all other games — puzzle-solving boiled down to its Platonic essence. Strip away all the medieval garb, gibbering monsters and postapocalyptic dungeons from most RPGs and stealth games, and you’d have something that looks pretty much like PQ.

Which is precisely Steven Johnson’s point. Beneath the surface of every game, there’s a gymnasium for your mind.

It would be pretty hilarious if games took seriously their role as cognitive food, and, like boxes of cereal, began proclaiming their nutritional value: “This game will stimulate your prefrontal cortex 500 percent more than an episode of Everybody Loves Raymond and 75 percent more than reading The Washington Post!!” But of course, the very fact that we still ruminate on whether games make you smarter or dumber is a symptom of how games are still coming of age in our mediasphere. Nobody sits around debating whether the act of reading stimulates your mind, after all.

But if you’ll excuse me now, I’ve got to get back to some mental exercise. By this time tomorrow, I should be 24 years old.