It's easy to think of IQ as something fixed: You take the test and it tells you how smart you are. But that's not actually how it works; intelligence is far more fluid than previously thought, and your brain is a lot more malleable than it is rigid.

Neuroscientists are now clear that adults are capable of changing their IQ--both for better and for worse. Here are a few ways to keep yours trending up and to the right:

1. Play chess

There's a reason chess has been played for centuries, and by royalty. An intricate and complex game, it develops your problem-solving skills, improves your concentration, and stimulates both sides of the brain, which helps strengthen your corpus callosum.

The corpus callosum is the part of the brain that connects the two hemispheres, and experts theorize that part of the reason Einstein was so brilliant was that his was particularly well-developed. He could access his entire brain all at the same time, instead of only one or the other part.

According to a study out of Venezuela, children who took chess classes for 14 weeks significantly increased their IQ. Another 2003 study out of Flinders University in Australia came to the same conclusion: participants who played chess demonstrated improved IQ levels.

2. Do sprints

The neuroscience is clear: aerobic exercise is extremely good for your brain. In fact, working out raises your IQ far more than playing an online brain game. Plus, a Swedish study proved that cardiovascular fitness can actually raise your verbal intelligence by 50%. Said Maria Aberg, who led the study, "Increased cardiovascular fitness was associated with better cognitive scores. In contrast, muscular strength was only weakly associated with intelligence."

So if you want to be smarter, don't just lift; do sprints.

3. Take creatine

Research out of the University of Sydney showed that if you take 5g of creatine daily, you can lift your IQ by a full 15 points over a six-week period. Said study leader Caroline Rae, "Creatine gave a significant boost to brain power." Why? In part because it lifts the energy levels available for computation in your brain.

4. Start meditating

Countless studies find that meditating for as little as 20 minutes a day not only boosts your mood and lowers your stress levels, but also improves efficiency when it comes to deep cognitive processing. This is core to fluid intelligence, and part of what helps you become truly innovative.

If you replaced 20 minutes of surfing Facebook with 20 minutes of meditating using an app like Calm or HeadSpace, you'd get smarter and lose absolutely no value in your life.

5. Get enough sleep

According to science out of Loughborough University's Sleep Research Centre, every hour less than the recommended eight hours of sleep a night can knock off a full point from your IQ.

In fact, their report concluded that regularly losing two hours of sleep a night can cause someone with an average IQ to become "borderline retarded."

6. Learn a new language

According to neuroscience, learning a foreign language makes your brain grow. Because you're navigating a new set of complex rules (such as grammar different from your native tongue), it forces cortical thickening and increases in the volume of your hippocampus. In plain language, that means you're causing the language centers in the brain to expand, which eventually helps with other language tasks like negotiating, reading, and problem-solving.

Again, this doesn't have to take a long time. Download DuoLingo for free and start learning any foreign language in as little as ten minutes a day.

7. Take up the guitar

A study out of the University of Zurich showed that becoming proficient in a musical instrument can raise the IQ of both adults and children. We're not talking about insignificant gains, either: the average IQ score in the United States is 98. Playing music can raise your IQ by 7 points or more--you could go from 98 to 105 just from learning how to strum Free Fallin'.

Plus (and just in time for summer), you'll be a campfire hero.