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Why Do People Fall In Love? 8 Scientific Reasons

8 Secrets (From Science) For Falling In Love

By Jennifer Acosta Scott Medically reviewed by Lindsey Marcellin, MD, MPH

People fall in love every day — but when a twosome goes completely gaga over one another, what’s going on in their brains?

Over the past few decades, many researchers have looked at the so-called “rules of attraction” — what it is about our chemical makeup that sparks up chemistry with another person. “It’s never just one thing, like facial symmetry or pheromones,” says Brian Grossman, PhD, a psychologist and communication expert in Los Angeles. “But there are some concrete, specific issues that lend themselves to immediate, long-term attraction and relationships.”

Ever wondered what it is about your honey that got you hooked? Perhaps it’s one of these fall-in-love factors.

Political Parallelism

Why People Fall In Love

Political Parallelism

Think it was his clever sense of humor or killer pot roast that had you falling for him? Turns out, it probably had more to do with his voting history. A recent Rice University study published in the Journal of Politics found that we tend to choose partners with similar political views — in fact, couples who swing the same way politically outnumbered those with similar personality traits, appearances, and religious beliefs. And that makes sense, says Dr. Grossman: “It would be hard to have a relationship long-term with someone with a dramatically different political view. It’s a different value set, which goes to our core.”

A Woman's Measurements

There's no denying that physical appearance plays a big role in romantic attraction -- but who knew it got this specific? Researchers at the University of Texas found that women with a low waist-to-hip ratio (in which the waist is significantly narrower than the hips) are more attractive to men than those with wider waists.

What's in a waist size? Researchers believe that a good waist-to-hip ratio may subconsciously signal to a man that a woman has good health and reproductive ability. "We can't help but look at health and attractiveness," Grossman says. "Heavier people have a harder time. But it's not something we do consciously. No one's ever gone to a bar and seen a woman and said, 'Wow, look at her waist-to-hip ratio, she looks great!'" Chalk it up as one of those subliminal rules of attraction.

Chivalry (It Isn't Dead)

If you're one of those types who puts others first, you're in luck: You may have a greater chance at a satisfying, healthy relationship. A survey by the University of Chicago showed that people who agreed with altruistic statements, like "I'd rather suffer myself than let the one I love suffer," reported more happiness in their marriage than those who did not concur with those statements.

While it's not all that surprising that altruistic people have better relationships (they are more likely to be considerate and thoughtful toward their spouses, says Grossman), there's a fine line between being selfless and a people-pleaser. It's important to know how to say no (for example, when you're overextending yourself), or you may end up doing damage to your emotional health.

A Symmetrical Face

Could it have been your partner's evenly spaced eyes that got you all starry-eyed? An Australian study found that, subconscious though it may be, women tend to prefer male faces that are symmetrical (which is often considered a sign of good health). "It's a survival of the fittest thing," Grossman says. "We subconsciously look at their face and say, 'That's a great face -- our kids are going to look awesome!" This judgment is a quick one, too -- it takes more than a nanosecond, but less than a second, says Grossman.

Your Postal Code

No one likes long-distance relationships -- but that has little to do with why someone's address impacts whether you'll be romantically attracted to them. Instead, it has to do with cultural values: If you're raised in one place, your idea of attractiveness may be completely different than that of someone raised somewhere else.

In fact, a study published in the journal Psychological Science found that men who live in cultures where food and money are scarce tend to find heavier women more attractive than thinner ones. These men may see the extra pounds as a status symbol; a buxom figure signals having the means to purchase plenty of food. Given these findings, it's not surprising that super-skinny people are idealized in places where there are plenty of resources to go around.

The Number Of Candles On The Cake

We've become a culture that's obsessed with defying age -- and research may help prove why: A study from the journal Current Anthropology found that men from five different cultures showed a preference for females with youthful features like large eyes, a small nose, and full lips. Don't be too quick to write these men off as pigs, however: These findings show that we subconsciously seek out partners who are most likely to be able to reproduce. And though the study didn't examine women's preferences, Grossman is willing to bet that females have similar penchants for younger-looking partners.

But Grossman warns that physical attraction doesn't always add up to a healthy relationship. Though a 65-year-old man might find a 20-year-old woman attractive, they're probably not a great match. "A more than 25- or 30-year difference is always difficult to overcome," he says.

Mirror Images

Opposites may attract, but that doesn't mean they're a match made in heaven. In fact, recent research has helped explained the phenomenon of doppelganger couples. While participants in a Canadian study were less likely to choose people with similar-looking faces for a short-term relationship, they were more trusting of people with faces that resembled their own -- and therefore more likely to end up with them in the long term.

The researchers theorize that this response evolved to prevent accidentally becoming sexually attracted to relatives, while at the same time guiding us to fall in love with long-term mates who are reasonably similar to us. "We do not want to date relatives, but we do trust people who are similar to us," Grossman says. Now we realize the whole 'opposites attract' thing is lust.. Most opposites don't stay together long-term."

Your Genes

The types of relationships you forge may be influenced by your genetic makeup. An Italian study found that people with certain relationship styles were most likely to carry specific biological markers in their brains. This may indicate that biology plays a factor in our romantic attractions, but it doesn't mean that our fall-in-love behaviour can always be forecasted by science. "I absolutely believe a lot of behavior is predictable," Grossman says. "But can you prove this, exactly, every time? No. You can make specific predictions of people, but there are always things that we haven't been able to quantify, like emotions and the human heart. There will always be outliers."

Bottom line? The rules of attraction can't be written in stone -- which is why love leaves even the best of us mystified.

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