The Most Important Trait For Attraction —​ And How It Leads To Love

World-renown biological anthropologist Dr. Helen Fisher on why we like who we like.

brunette couples about to kiss in the woods, smiling Standret / shutterstock 

An anthropologist once asked a Kung Bushman living in a hunter/gatherer band in the grasslands of Botswana if he would marry a woman who was smarter than he was.  

He replied, “Yes, because she’d make me smart too.”  

Today 80 percent of singles say they “must have” or find it “very important” to have someone of the same level of intelligence. And 89 percent would make a commitment to someone who is “considerably” better educated and/or more intellectual than themselves.


Why do we want a smart partner?  

Because intelligence comes with a host of perks. It is correlated with having a higher income and a keener sense of humor, as well as with creativity, social savvy, motor coordination and skill at solving problems.  

“Smart” anchors a relationship. And a host of data I have collected with on a representative sample of Americans now illustrates that we are naturally drawn to someone with our level of intelligence.  

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Like seeks like

Other factors play a role in mate choice. Timing is important. If you’re not ready, you won’t notice the smartest person in the room, even if he or she is sitting on your lap.  

We tend to fall for someone of the same socio-economic background, degree of good looks, same religious and social values and the same reproductive goals.   

Oddly, basic body chemistry also plays a role.

People often say, “We have chemistry.” To find out what they mean, I collected data on any brain system linked with any personality trait. 

Indeed, we humans have evolved four broad styles of thinking and behaving, associated with four major chemical systems in the brain: the dopamine, serotonin, testosterone and estrogen systems. 


If, for example, you are highly expressive of the dopamine system, what I call an Explorer, you tend to be risk-taking and novelty-seeking, as well as spontaneous, energetic, curious and creative.  

And after studying the dating choices of over 50,000 members of (a subsidiary of, I found that Explorers gravitate to other Explorers.  Be they backpackers who explore the world or urbanites interested in symphony or poetry, Explorers are drawn to individuals who join them in their physical or intellectual adventures.

Builders are men and women who are highly expressive of the traits linked with the serotonin system and also seek a partner like themselves. These men and women are cautious and traditional. They respect authority, follow the rules, enjoy schedules and tend to be orderly and conscientious. And they seek a partner equally eager to build a family, home and community.  

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When opposites attract for romance

But the other two biological types, the Director and Negotiator, seek their opposite: one another. Directors, who are particularly expressive of testosterone, tend to be analytical, direct, decisive, tough-minded and good at things such as math, engineering, mechanics, computers and/or music.  

However, they are particularly attracted to the high estrogen type, Negotiators, those who see the big picture and are imaginative, intuitive, compassionate and verbally and socially skilled

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Most people defy strict labels for styles of thought

Each of us is a complex combination of all these brain systems and their associated styles of thought and action. But we do have distinct personalities — based, in part, on our biology.   


Nevertheless, you can walk into a room filled with people of your type–and you don’t fall in love with all of them.  

Here’s where intelligence comes in. 

Among that array of potential partners, you will still seek those similar to you in intellect. 


Intelligence comes in many varieties. And when you first meet someone, you tend to over-weigh the few things you know about him or her, then evaluate them on these morsels of information. Give a potential partner a chance to show their brilliance. 

The more you get to know someone, the more you like them and the more you think they are similar to yourself. You might even trigger your brain circuitry for intense romantic passion. “Smart” is an aphrodisiac for love.

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Helen Fisher Ph.D., is a biological anthropologist and Senior Research Fellow at The Kinsey Institute and Chief Scientific Advisor to the dating site Match. She is the author of the book The Anatomy of Love: A Natural History of Mating, Marriage, and Why We Stray, among other titles.