The 1989 movie "When Harry Met Sally…" features several elderly couples speaking to a documentary filmmaker about how they fell in love. These couples seemed to know instantly that they were meant to be together forever, though for some of them, there were a few challenges (and other partners) to overcome. That immediacy was not how it worked for Harry and Sally; the meeting referenced in the film's title wasn't filled with fireworks or long romantic gazes. Neither party walked into a room, spotted the other one and was overcome by certainty that he or she was the one.
For Harry and Sally, it was a long path to romance, which makes them a rarity among Hollywood soul mates. How many movies have you seen where a glimpse across the room is enough to convince a protagonist that the search for love is over? Sometimes, such a scene can seem insane -- how can he be in love with someone he hasn't even spoken to? How can she be so dumb to mistake that feeling for anything else but lust? But the feeling of love at first sight isn't limited to film, because there are plenty of couples who claim to have experienced the sensation in real life as well.
Hollywood directors aren't the only ones who have grappled with whether love at first sight is possible. Neuroscientists, anthropologists and evolutionary biologists have also explored the question, and we'll focus on their work in this article. Read on to find out what fruit flies and blind people can teach us about love.
Falling in Love in Three Minutes or Less
Helen Fisher, a prominent anthropologist known for her research on attraction and love, believes three minutes is all you need to know whether someone will be in your life for a while [source: Fisher]. To understand her theory, we have to travel back in time to the days of early humans. Our ancestors lived shorter lives than we do, and it was important in their brief time on Earth to mate and produce a healthy child so that the race would live on. For this reason, they had to size up potential mates quickly, just as they had to quickly size up whether a stranger was friend or foe. Fisher believes our evolutionary past wired our brains so that we know pretty quickly whether we might want to mate with someone (even if we're not even looking to have a child).
So what are we considering in those three minutes? Many scholars speak of the concept of a "lovemap," a laundry list of traits that we want in a partner, which means that when you told a girlfriend that your next boyfriend needed to be tall and have a sense of humor, you were actually working on a lovemap. But while you may have some ideas about what you find attractive in a potential paramour, these ideals of beauty were likely influenced by those evolutionary ancestors again.
Men and women both wanted to ensure that their children would live and pass on their genes, so they needed to be sure that the other party was bringing the best genetic makeup to the table. We often signal our physical and reproductive health with traits like a certain waist-to-hip ratio or a symmetrical face; scientists have found that these qualities are universally attractive to others. And when you check out a guy's chin or a lady's lovely eyes, you're actually looking at traits that are shaped by the amounts of testosterone and estrogen in their bodies, respectively, which also indicate reproductive fitness. So when we comment on someone's hotness, we're actually commenting on ancient ideals of fertility.
So we can tell pretty quickly whether someone will give us a cute, healthy baby. But is that love, or just lust? Fisher points out that the sections of the brain that respond to love and lust are different, though they can light up at the same time. In a study conducted at Syracuse University, researchers found that the hormones associated with love, rather than lust, can flood the brain in one-fifth of a second [source: Syracuse University]. It seems to indicate that our brain can start feeling amorous pretty quickly, but on the next page, we'll consider more elements of the lovemap and what else might be going on in that 0.2-second to three-minute time span.
Your Brain's Love Checklist
On the last page, we talked about how age-old signs of fertility can make our brain (and perhaps our sexual organs) take notice of another person. But you might be saying to yourself that love is more than a physical attraction to someone, and it's true that other things are going on when you first encounter a potential mate. For one thing, without sensing it, your brain is sizing up this person against all other past loves. If you're taking notice of a guy with a baseball cap, your brain may nudge you with, "Hey, remember that last man you dated who wore baseball caps? That didn't go so well." Or, your brain may be measuring visual cues against stereotypes about socioeconomic status. If you're spying someone with a briefcase and a business suit, your brain is helping you conclude that this person may work a lot, but at least they can afford a few nice dinners every now and then. Though this insight may disappoint romantics, your brain is only trying to protect you and your assets so that you don't date a broke man who wears baseball caps like your last dud of a boyfriend.
While you're making small talk, you're sizing up his or her voice. A male who speaks deeply and quickly, for example, is likely to be rated as better-looking and highly educated by women around him, according to some studies [source: Fisher]. And of course, if your date is saying things that jibe with your worldview, then you're going to be further besotted. Though we often hear that opposites attract, scientists say it's far more likely that we practice assortative mating, which is partnering off with people who are similar to us. Successful couples may share the same religious values and tax bracket, and they tend to be "in the same league," looks-wise. Yes, what you learned in high school is true -- the pretty people tend to stick with their kind. One study found that people tend to choose people who have the same level of body fat [source: Rowett Research Institute].
Of course, we don't want someone who's too much like us, genetically -- remember our ancestors' mandate to find someone who could make a baby with the best chance of survival? That's why researchers believe that smell is involved when we're sizing up the opposite sex. On the next page, we'll consider why love at first sniff is just as important as love at first sight.
Smelling Good and Looking Back
You're a single lady at a crowded party, and you've just locked eyes with a man who meets with all of your mental criteria. He's made his way over, and the three-minute clock that Helen Fisher wrote about has started. If he had body odor, that would be a deal breaker, but is it possible that you can sniff out whether he's a good match in other ways?
On the last page, we talked about being attracted to people who are the same to us, looks-wise. But remember, we learned how we're also all subconsciously evaluating the genetic card this person has to play for our potential offspring. The risk of falling in love with someone too much like you is that you might be related, and inbred offspring don't have a very good chance of survival. Some researchers think that while we're sizing up how nice another person looks, we're also somehow sniffing out their genes. One famous study found that women who sniffed sweaty shirts and ranked them in terms of attractiveness tended to rank shirts that belonged to the most genetically different men the highest [source: The Economist]. And in one study of fruit flies, researchers found that one meeting was all it took for the female fruit flies to figure out which males were their best genetic match [source: Moskowitz]. While humans aren't fruit flies, the researchers posit that we possess some similar search mechanism.
Perhaps you're seeing how difficult it can be to fall in love at first sight -- the person in question has to posses the right genes and look like someone we could be with, according to our mental love maps. But just as important as finding a person who looks LIKE us, though, is finding a person who looks AT us. In a study published in the Proceedings of the Royal Society, one researcher likened love at first sight to narcissism, because it turns out what we're most attracted to is someone who happens to be looking at us. Again, this has evolutionary roots, as we shouldn't spend time chasing a mate who's not interested, but it's narcissistic because the person we tend to look at, of course, looks like us. It's like falling in love with your own image in the mirror.
And just to make it more complicated, it might all come down to what time of the month you spy a lovely lady or a handsome gent. There's evidence that women become more attuned to certain traits in men during the most fertile times in their menstrual cycles; specifically, women tend to respond more strongly to potential suitors when they're ovulating, and men, in turn, tend to find women more attractive during the same period, even when the men don't know the lady's cycle. One interesting study even found that exotic dancers tended to receive much higher tips at their most fertile points of the month [source: Canning].
Want to learn more about love? We've got plenty of links on the next page to get you started.
Are women hardwired for monogamy or are a bunch of boyfriends the way to go? Learn about women, monogamy and evolution at HowStuffWorks.
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- Singleton, Dave. "Love at First Sight: Possible?" Happen Magazine via Chemistry.com (April 18, 2011)http://www.chemistry.com/datingadvice/Love-At-First-Sight
- Syracuse University. "Falling in Love Only Takes About a Fifth of a Second, Research Reveals." ScienceDaily. Oct. 25, 2010. (April 18, 2011)http://www.sciencedaily.com/releases/2010/10/101022184957.htm