Spring is the season for love, scientifically speaking

For anyone who's survived a Minnesota winter, a nice day in April seems to be about as close as you can get to perfect. When the weather warms up, instead of wind chill, it's love that's in the air. Why is that? Science of course.

Spring is a season of cliches -- birds singing, bees buzzing and people falling madly in love. If you're a scientist though, the love sickness can be blamed on one very real thing.

"It's dopamine," says Helen Fischer, a neuroscientist, professor at Rutgers University and author of five books on the science of love.

Fisher says dopamine is a naturally occurring chemical your brain uses to make you want things. There are other systems involved in love, but when it comes to new love, dopamine is the main culprit. And with enough of it swirling around your system, you're prone to fall in love -- and fall hard.

What does this have to do with spring? Dopamine is triggered by novel experiences.

"And there's so much novelty in the spring," said Fischer. "There is so much more color, new smells, people take their clothes off and you can see more of them. And so there is a lot of new stimuli that trigger the brain and drive up dopamine, and make you more susceptible to love."

Every April your brain unwittingly becomes a dopamine factory, turning you into a love junkie. In fact, brain scans of people flooded with the stuff look a lot like brain scans of drug addicts. Which makes sense, since being high on dopamine feels, as many lovers would put it, euphoric.

Every April, your brain unwittingly becomes a dopamine factory, turning you into a love junkie.

You can find plenty of couples feeling that high at the Bryant Lake Bowling Alley in Minneapolis on "Cheap Date Night." Some of them have been together so long they can't remember the start of it all. Others have better memories.

"Two years, seven months and one day!" said Matt Covell and Paola Rodriguez in unison.

"Sunday was our two years and seven months [anniversary], so I made a big deal out of it," Rodriguez said, while Covell admitted he doesn't remember the date as well.

The connection between these two young lovers may have more to do with science than they know.

Take their first kiss. It was a day after a big college dance.

"I wasn't sure if he liked me, but he was acting like it," Rodriguez said.

But they ended up hanging out late into the night, talking and flirting.

"It was close to finals, I was tired," she remembered. Then, around 6 in the morning, "he kinda just said he wanted to give me a kiss, and that's how it started."

Enough with the romance. Let's cut to the science.

With that kiss, two things happened. First, Matt slipped Paola an aphrodisiac. Male saliva has trace amounts of testosterone in it, which is known to boost the sex drive. A sloppy kiss can get things started in more ways than one.

Second, Paola began a subconscious screening process. Women's sense of taste and smell are especially attuned to something called the Major Histocompatibility Complex, or MHC. It's a series of genes responsible for our immune systems.

Study after study has shown that women prefer men whose MHC is different from their own. It means less immune system overlap and a chance for healthier kids. Scientists think that women can read a partner's MHC in their saliva. So a bad first kiss can be the sign of a bad genetic match.

Fortunately, that wasn't the case for Rodriguez and Covell.

"He has very nice lips, and it was sweet!" she said.

Their romance started in the month of May, so seasonally triggered dopamine may have played a part. But Helen Fischer says people under the sway of dopamine don't always see things as they are.

"The first thing that happens when you fall in love is the person takes on what I call special meaning. You can list everything you don't like about him and her, but you sweep that aside," she said.

And when you've been together a while, like say, two years, seven months, and one day, that dopamine rush can wear out, leaving you a clearer picture of what you've got.

Back at the bowling alley, Covell and Rodriguez are thinking about their future. They've been dating long distance and it's getting hard.

"We definitely know there is a always a possibility to break up. We are pretty realistic about it," Rodriguez said.

"I think we are both kind of looking for that breakup moment," Covell continued. "We don't know how it's going to happen or if it's going to happen."

"But I guess we just love each other," Rodriguez added. "We like spending time together, and it's just that hope that it will work out that keeps us going."

They're real to the fact that hearts are constantly going through cycles of frost and thaw, just like the chemicals in our brains ebb and flow and the planet rocks back and forth from the sun.

The sweetest moments never last, but that only opens up the chance for us to stumble into them all over again.

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