You often hear the phrase "love is a mystery." But new science is showing there are actually some chemical explanations as to why we love and how we choose our mates.

It could be a kiss, a hug, or something as simple as a look. We as humans show love in all sorts of ways. But what makes us fall into it?

New research is proving it may have a lot more to do with our brain and chemical make-up than previously thought.

“To explain this complex thing we call love requires an awful lot of science,” said Larry Sherman, a neuroscientist at the Oregon National Primate Research Center. “We know that certain phases of love are linked to certain areas of the brain,” explained Sherman.

In his research of primate behavior he's come to better understand human behavior. Sherman says the process of "falling in love" is like a journey through the brain.

A journey that begins with an initial attraction. “There’s this part of the brain called the orbital frontal area it right under here, and this area lights up like a christmas tree. The eyes lock and you see someone across the room and its like 'oh,'” said Sherman.

But new research suggests smell may be just as important. If your mate smells good to you, that may mean their chemical make-up will compliment yours and make it easier for you to reproduce.

“There’s good behavioral studies to suggest that smell plays a role,” said Sherman.

Our chemical make-up also may be the reason why we stay with partners - or don't. “There’s another chemical Oxytocin. If that kicks in you're going to have stable relationship you're going to want to stick with that person,” stated Sherman.

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Scientists studying prairie and meadow voles found that prairie voles, which mate for life, process oxytocin much better than meadow voles, which are known to be promiscuous.

“So could we make a love potion that makes your only monogamous right,” said Sherman.

The jury is still out on how Oxytocin affects humans, but science is showing it just might be the reason some humans are more prone to get married and others are not.

We all know love works in mysterious ways. But it’s a mystery science may now be helping to solve.

More: OHSU presents "Brain chemistry for lovers"