Music is an especially human phenomenon.Animals and even songbirds, oddly, don’t hear melody the way we do. And although an estimated 10 percent of the human population doesn’t enjoy music, most of us seem to naturally know that it can have a powerful impact on our mental health, and can make us feel more beautiful.Neuroscientists know why. If you like Joni Mitchell’s hit song “Big Yellow Taxi,” the very first bars click the on button to your brain’s reward centers: the nucleus accumbens, the amygdala and other parts of the brain that vary the level of dopamine, a chemical even scientists call happy juice. Singing together also produces oxytocin, a trust hormone released during female orgasm. A “brain on music” lights up like a Christmas tree.QUIZ: Feelin’ Groovy? Take the Happiness Quiz People enjoy variety in music because our brains are constantly trying to predict what will come next in any musical sequence. We love complexities, so master musicians and composers set the rules and subtly break them with nuances—just enough to keep us engaged and still grounded.Some people like more predictability, others less. Small children like a lot. Ask any parent trapped with Barney’s “I Love You” on a long car ride. (Those bits that stick in your head have a scientific name: earworms.) Kid music is irritating because an adult brain craves variety and gets so much pleasure from it.Music tickles the mind, which may be one of the reasons why Americans spend more on music than on prescription drugs, reports Daniel Levitin, author of “This is Your Brain on Music” and “The World in Six Songs: How the Musical Brain Created Human Nature.” Music has been shown to reduce pain by 21 percent, reduce depression by 25 percent and boost immunity.MORE: Why Older Women Love BieberYou might try putting on your favorite relaxing music when you have a headache or virus. Is music an anti-depressant? People have used it for that purpose for centuries. As Levitin puts it, he was with Joni Mitchell once when a fan confided to her, “Before there was Prozac, there was you.”Just about any music can be downloaded for free these days in some version. But concerts are still a good buy. Money spent on an experience leads to more lasting happiness than products like a new dress. Let’s say your choice is between $300 for tickets to four concerts or a professional teeth-whitening. Chances are when you’re glowing and humming the day after a concert, you’ll get compliments on your beautiful smile—even with average-looking teeth.Happier people also find it easier to follow the core of a beauty routine—restful sleep, exercise, a balanced diet, time for fun with friends and family, and loving sex—the truest source of clear, bright complexions and eyes.Listening right before work—or even when you’re working at home—may be a good habit. A recent study found that people solved problems in a more creative way when they listened to peppy music—in this study it was Mozart. “If you have a project where you want to think innovatively, or you have a problem to carefully consider, being in a positive mood can help,” says co-author Ruby Nadler, a psychology graduate student at the University of Western Ontario.But don’t feel stuck with Mozart, Nadler says. Our taste is tied to our history. Experiments have even shown that one-year-olds remember music they heard in the womb. And people with severe memory loss from dementia often burst into perfect renditions of songs they first learned when they were fourteen, a time of self-discovery and strong emotions, when our amygdala tagged memories as important.This means that the fact that you’re clueless about opera or the latest pop scene shouldn’t let you drift away from music you do know and love.When branching out, there’s a simple test for how a song is likely to affect you. Your heartbeat responds to the beat of the music, says Joshua Berrett, Ph.D., a professor of music history at Mercy College in Dobbs Ferry, New York, and co-creator of musicandhappiness.com. So if you want to calm down, choose a slower beat; to rev up, the opposite.To calm down to sleep: A resting heartbeat is normally between 60 and 100 pulses a minute. Music at a slightly slower tempo may relax you or lull you to sleep. Berrett suggests “Summertime” from the Miles Davis recording of “Porgy and Bess,” for an example of cool jazz, or for classical, Claude Debussy’s “Nuages.” Chopin’s “Berceuse in D flat” is a grownup lullaby: “It has a pattern in the bass that imitates the rocking of a cradle,” Berrett says.To improve mood: Up the tempo a little to 100 to 120 pulses a minute for a calm, grounded joy. A classic example is “California Girls” by the Beach Boys. But any music with sound elements or instrumentation you enjoy around that tempo could do the trick, Berrett says. To get moving: Classic march songs for soldiers are 120 or 140 beats per minute, notes New York songwriter Richard Winter. Love disco? Try “Hot Stuff” by Donna Summer. Popular energizing songs tend to be around 130. Winter suggests U2’s “Beautiful Day,” which has a tempo of 136, or the punk rock band Green Day’s “Know Your Enemy” at 130. “It’s electrifying,” he says. “These guys are full of juice!” Or think about every wedding where you’ve seen women running to the dance floor when they hear ‘It’s Raining Men,’” the Weather Girls hit.MORE: Is Too Much Noise Blasting Your Beauty?You’re too private to wiggle on the subway? You’re still getting some of that aerobic-mood-enhancing effect. Most languages don’t make a distinction between music and dance and when people are perfectly still listening to music, the neurons in the motor cortex—responsible for movement—are firing. We “dance” in our heads—even if don’t move.Also, it’s a mistake to resist singing along because you believe you lack talent. There appears to be no biological base for exceptional musical talent. Even people who consider themselves unmusical can attain close to perfect pitch, Levitin says. Humans are so naturally musical that we can identify familiar songs solely by the pitch and rhythm, even when they are played with power tools.So next time you need a mood boost, simply turn on the radio to find your lovely groove.In related news, check out this humorous take on what your taste in music says about you on a date.