Playing Brain AgeAnyone who has ever begged their parents for a videogame system knows the standard lines of appeal ("You don't want me to have inferior hand-eye coordination, do you?"). Now kids can argue that some games may make them smarter. That's the promise of Nintendo's Brain Age, which claims to "help train your memory and keep your mind sharp" through reading exercises, math puzzles, and other mental gymnastics. After diligent effort, players routinely see their "brain age" plummet from, say, a sluggish 60 to a taut 30.

But the improved performance may not be a sign of wit-sharpening. Many users start with little gaming experience, so it's not surprising that their scores improve — a phenomenon known as the practice effect. Sadly, there's no evidence that in-game gains translate to the real world. — Greta Lorge

Doing Crosswords__Completing__ that Sunday New York Times crossword puzzle isn't just a diverting — if usually futile — pastime. It's also a great way to keep your wits about you as you age. At least that's the common belief, which holds that a regular schedule of cognitive exercise can bulk up your brain with new neurons, the same way vigorous weight lifting can build muscle mass. You can continue to sprout new neurons well into adulthood, but they will be only as powerful as the neural networks they're connected to. And it's not clear that puzzles help forge those connections.

Some studies have reported that mental exercise can slow or reverse cognitive decline. But aging expert Timothy Salthouse of the University of Virginia says the evidence is all correlational, not causal: The respondents who were most drawn to mental exercise or pursued brain-intensive professions probably had greater cognitive reserves to begin with. So no, crossword puzzles probably won't fend off senility. What's a four-letter word for "commonly held but unproven belief"? Oh, right: myth. — G.L.

Eating Fish__Herman Melville__. Ernest Hemingway. Schröedinger's cat. Some of our brightest minds had a thing for seafood. That may be no coincidence. Oily fish are rich in docosahexaenoic acid (DHA), an omega-3 fatty acid that accounts for 40 percent of the makeup of brain cell membranes and which could improve neurotransmission. DHA is necessary for fetal brain development, and a handful of studies have linked fish-heavy diets with reduced risk of mental decline in old age.

But before you take the bait, consider: Those studies trusted subjects to remember and report their dietary habits — a fishy procedure. A test of mice found that an omega-3-rich diet had no impact on cognitive function. And cold-water fish that are high in omega-3s are also likely to have elevated levels of methylmercury and PCBs, both known neurotoxins. It would be great if fish really were brain food. Unfortunately, we've got to throw this one back. — G.L.

Chewing Gum__School principals__ may scoff, but the notion that gum enhances alertness dates to World War I, when sticks were slipped into soldiers' rations. The rationale: Chewing increases blood flow to the motor cortex and can trick the brain into expecting a meal. This triggers an increase in insulin production that could boost cerebral glucose levels — and thus smarts. Too bad a 2004 study found gum chewers to be less attentive than a control group. Looks like Mrs. Snodgrass was right after all. — G.L.

Listening to Music__Music can certainly__ expand your mind; if you don't believe us, play Dark Side of the Moon while watching The Wizard of Oz. But can it amp up your brain power? That's the claim of companies like the Monroe Institute, which market CDs and MP3s that promise to increase focus and improve memory.11 This ain't Baby Bach: The recordings pump a different frequency into each ear, and these tones mix in the brain to produce a pulse that supposedly shifts the firing pattern of neurons, altering brain waves and – the thinking goes – reverse-engineering the mental state that accompanies them.

A compelling idea, but it's less likely to produce serious thought than a Fergie concert. In a recent study at Oregon Health and Science University, subjects exposed to a binaural pulse in the 3- to 8-Hz theta band (which is linked to working memory) showed no change in brain wave activity as measured by EEG. What's more, they actually became depressed and forgetful. If you wanted that, you'd just listen to Celine Dion. — G.L.

Taking Supplements__The supplements industry__ claims its products can boost your intelligence. Intelligent enough to check out the scientific basis for those claims? Pill purveyors better hope not. Here's how a few remedies rate on our snake oil scale. — Mathew Honan

B Vitamins

Summary Useful for staving off Alzheimer's, but don't expect it to help you solve that sudoku.

Snake Oil Rating

Ginkgo Biloba

Summary It may come in handy during your sunset years, but until the dementia sets in, this won't help.

Snake Oil Rating

Ginseng

Summary Might regulate glucose, which may improve cognition, but that's a whole lot of maybe.

Snake Oil Rating

Gotu Kola

Summary It reduces anxiety in rats, but for humans the only provably "smart" thing is the marketing.

Snake Oil Rating

Huperzine A

Summary One study showed memory improvement in healthy adults, but more solid evidence would be nice.

Snake Oil Rating

Related Get Smarter: 12 Hacks That Will Amp Up Your Brainpower 1: Distract Yourself 2: Caffeinate With Care 3: Choose Impressive Information 4: Think Positive 5: Do the Right Drugs 6: Juice Your IQ Score 7: Know Your Brain 8: Don't Panic 9: Embrace Chaos 10: Get Visual 11: Exercise Wisely 12: Slow Down Plus: 6 Intelligence Myths Exposed