When Opposites (Seem to) Attract: How Does Science Explain Sexual Chemistry?

Why are some couples dramatically different, while others could be mistaken for siblings? Turns out it’s all brain chemistry. (Photo: Jon Kopaloff | FilmMagic | Getty Images)

If you watch The Mindy Project, Mindy Kaling and Chris Messina’s People Magazine Awards win for Onscreen Couple of the Year was not a shock last Thursday night. The two actors have amazing (and hilarious) chemistry as feuding-and-flirting OB/GYN duo Mindy Lahiri and Danny Castellano.

Their characters also embody the concept of opposites attracting, with different cultural and religious backgrounds on the show, as well as different interests and habits. They just don’t have the “look” of a quintessential onscreen couple, do they? And yet they work so well.

Which, of course, plays out in real life, too. We’ve all seen that couple walking hand-in-hand on the street and thought, ding, ding, ding! There’s a match. We’ve also seen that happy-go-lucky odd couple bantering at a party and thought, Hmm… interesting.

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First off, before we dive in, let’s define chemistry. Chemistry is a sense of “fit,” or what scientists would call a couple’s compatibility. Science has some different theories on what draws one person to another and causes them to stick.

The perspective of chemistry in psychology is pretty straightforward, at least at a baseline level, according to Gary W. Lewandowski Jr., Ph.D., chair of the Department of Psychology at Monmouth University and co-founder of Science of Relationships.

“More often than not, we’re attracted to those who are similar to us,” he tells Yahoo Health. “We generally like ourselves, so finding someone who is similar makes that person even more likable.” And early on, liking someone (and falling for that person) has everything to do with visual chemistry, Lewandowski says, which is why we often see people of similar attractiveness levels falling victim to Cupid’s arrow.

Visual chemistry might also explain why we try to peg matches from mere appearance. Our brains want to fit couples inside of cookie-cutters, as we put together people who we guess would have the most visual chemistry. “I think everyone likes to play armchair relationship expert and there is some recent research showing that being a matchmaker is enjoyable,” he says. “And though it seems superficial, the impact of physical attraction is undeniable and is one of the primary factors in relationship formation.”

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Since beauty is partly subjective, though, and can change when you know someone’s personality, this sometimes works out and sometimes doesn’t. But usually, underneath it all, psychology suggests that similarities lie at the core of most relationships.

So, what about that whole ‘opposites attract’ thing? It’s not exactly what it appears to be on the surface, says Lewandowski. “People often believe opposites attract because the differences with our partners are more noticeable, which is further evidence of similarity’s importance,” he explains. “A person who is opposite of you — you love decorating for the holidays, but your partner hates it — will lead to more conflict and relationship discord.”

And discord is something everybody tends to notice. It would explain the noticeable friction between the characters of Mindy and Danny.

So says psychology, anyway.

The anthropological perspective on sexual chemistry is a little different. Culturally and socially, we still do expect similarities to pool together, and those cultural influences can drive our decisions about whom we pair off with — at least in part. However, biological anthropologist Helen Fisher, Ph.D, Chief Scientific Advisor of Match.com and author of Why Him? Why Her?, says it’s more nuanced than an “opposites attract” or “similarities attract” phenomenon.

“Culturally speaking, we tend to attract people of similar socioeconomic backgrounds, education levels, intelligence levels, looks, and so on,” Fisher tells Yahoo Health. “That said, you can walk into a room with everyone meeting your list of criteria, and you won’t fall in love with everyone there. That’s because, biologically-speaking, certain kinds of people attract their opposites and other kinds of people attract someone similar — our biology is 40 to 60 percent of the equation.”

Years ago, Fisher researched the question of what exactly causes us to fall for a specific type of person, so she looked at the brain and its systems to see if certain traits were linked to certain systems that drive personality. She found four sets of traits linked to four different systems: dopamine, serotonin, testosterone and estrogen.

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If you know a little about brain science and hormones, you might be able to guess the characteristics linked to each system. Dopamine-oriented people are the thrill-seekers, who love novelty, spontaneity, and flexibility. Those driven by serotonin are generally traditionally-minded and conventional; they seek calmness, rules, and set schedules, and are often more religious.

Those fueled by testosterone are usually analytical, logical, skeptical, a little lacking in empathy, but great at math and science. Estrogen-oriented people are intuitive, emotionally-expressive, diplomatic, and imaginative, with great people and verbal skills.

Fisher developed questions to gauge how well people fit each biochemical system, and then had thousands of Chemistry.com users fill out a personality questionnaire. Finally, she watched to see whom those people responded to while selecting dates on Match.com.

Fisher found that, at a basic biological level, each biochemical system has certain preferences that drive the person’s mate selection. “The bottom line is, all opposites don’t attract,” she explains. Perhaps this is why research findings (and our perception of whether similarities or differences are better together) is so mixed.

The types that feel the pull? Serotonin tends to pair off with serotonin and dopamine tends to go for dopamine, whereas testosterone and estrogen tend to attract each other (meaning: their opposite).

Fisher guesses this is likely why Kaling and Messina can create such chemistry. She thinks the supersocial, emotionally expressive Kaling is probably driven by the estrogen system, whereas Messina is likely dominated by his testosterone. “She has that soft, round face and the estrogen figure — the hourglass shape,” says Fisher. “And Chris has that facial structure and heavy brow ridges built by testosterone.”

Obviously, real actors are not their fictional characters, and once we add in the real actors’ biologies, there’s an added variable. Their biologies will affect their personalities and the types of people with whom they’ll generate the most heat — onscreen or in real life.

It’s easy to see why a serotonin-driven person would also want a rule follower who likes set schedules (“a great relationship to raise children,” Fisher notes). It’s also not hard to imagine that someone with a preference for spontaneity and excitement, like a dopamine-dominant person, would also appreciate someone willing to drop everything and fly to France at a moment’s notice.

An “opposites” match, however? A little harder to figure out. But yet estrogen-centered people like Kaling often light it up with testosterone-minded people like Messina, according to Fisher. She thinks she sees how this relationship evolved, though.

Let’s take a trip back to ancient days. “For many years, they brought different things to the table that the other desperately needed,” Fisher explains. “Estrogen needed the technicality, decisiveness and spatial skills of testosterone — someone’s got to hit that buffalo in the head — whereas high testosterone needed the ability to read people, the empathy and understanding of estrogen. They have a clear, complementary relationship.”

(Photo: Getty Images)

Think of Hillary and Bill Clinton, as an example. (It’s counterintuitive on the surface, but not-so-much when you think about it: Hillary is testosterone, and Bill is estrogen.)

Now what does that symbiotic relationship look like? It’s kinda hot, actually.

As Lewandowski says, ultimately estrogen and testosterone are likely destined to have more conflict than those biological types who bond with similar someones. However, Fisher says this hormone pairing can make for a superdynamic couple.

A few examples? “Testosterone has a deep view of ideas and the world around them, whereas estrogen has a broad view to contextualize and put things into perspective. They have wonderful conversations, and they respect each other’s view,” Fisher says says. “Testosterone is also analytical, whereas high estrogen is intuitive. They absolutely mystify each other with their different forms of intelligence.”

It doesn’t end there, though. Testosterone is decisive; estrogen ruminates. Testosterone is blunt and direct; estrogen is nuanced and tactful. Testosterone gets stuff done in a flash; estrogen is all about the process.

These opposites are the perfect complements — even if their differences are downright frustrating sometimes, as they may be during a decision-making process or at turning points in the relationship.“I often talk to therapists seeing testosterone-estrogen pairings, where a man will come into the room and say, ‘I mean, I love her, but I don’t understand her.’ Well, they’re never going to understand each other,” Fisher says.

“They were built to be different than, yet fascinated by, each other. And they’re better whenever they put their heads together.”

If that’s the case, it’s no wonder Kaling and Messina won an award for their relationship chemistry. And now you know: Sometimes opposites do attract, other times similarities cause sparks. Whatever you think you’ve seen play out in real life, you’re probably not wrong.

Ah, chemistry. Whether it’s in the lab or on the screen, it’s pretty cool science.

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