6 Factors That Secretly Influence Who You Have Sex With

6 Fear

The Romantic Notion:

"If two people are meant for one another, it doesn't matter whether they meet in high school or prison -- love will find a way."

Science Says:

"Did you see a comedy or a horror movie on your first date? The answer to that question can determine who you end up sleeping with more than any of the "important" factors you pay attention to."

We tend to think that emotions such as fear and anger cause our hearts to speed up. According to the two-factor theory of emotion, it's the other way around. When you meet a 15-foot-tall grizzly bear in the woods, your body doesn't have time to ask your brain about feelings. Instinct takes over and turns your heart into an internal combustion engine. According to the theory, it's only later that we come up with "an emotional interpretation of that arousal" and decide we were scared.

Here's where it gets weird. If you experience the symptoms of fear around someone with your preferred brand of sexual organ, your brain will assume that your heart was racing because you were sexually attracted to that person. Seriously. Science even found a way to prove it.

In a study by Donald G. Dutton and Arthur P. Aron, two groups of males were approached by an attractive female research assistant and were asked to fill out a survey. One group was approached on a solid, railed-in foot bridge that was five feet off the ground, while the other was crossing a "five-foot wide, 450-foot long bridge" that had "a tendency to tilt, sway and wobble" and featured "a 230-foot drop to rocks and shallow rapids below."

The men dangling hundreds of feet above certain death were just as likely to stop for the hot lady asking them to do paperwork. Also, they tended to provide more sexual answers to the open-ended questions on the forms they filled out. What's really weird is that their confused terror boner didn't go away. Both groups were given a number where they could reach the female assistant in case they required any "clarification" on the surveys. The guys on the suspension bridge were five times as likely to call her the next day.

That's why this is bad news for your soul mate and good news for some idiot who happens to take you to a scary movie. The sexual charge we get from being scared while sitting next to someone doesn't just wear off as the credits roll. Fear makes that person more sexually attractive in your memories.

Scientists say women are just as prone to the scare-induced hornies, which probably explains why guys always decided that "Makeout Point" should be within 10 feet of a dangerous cliff. Being on a first date in a scary environment is basically like dosing each other's drinks with an aphrodisiac.

But scary movies aren't the only type that can screw with your ability to choose a partner. Ladies, let's say you take your soul mate to the latest Nicholas Sparks movie (you presumably don't know he's your soul mate yet). At a sad moment in the movie, you start crying, and he goes in for the cuddle. That slide whistle you just heard was his testosterone level dropping like a homesick rock. It turns out that female tears produce a hormone that dampens the male libido. According to the scientist behind the discovery, the purpose is evolutionary: "We've uncovered the chemical word for 'no,' or 'not now.' " While that probably came in handy when the dating scene was full of hunter-gatherers, in the modern world, this means that something as simple as a bee sting can scare away the person you're destined to be with for the rest of your life.

5 The Color Red

The Romantic Notion:

"Looks don't matter. It's what's inside that counts. Once a girl starts talking to you, she'll see the real you and fall in love."

Science Says:

Yeah, that's all fine and nice and romantic-sounding, but if you really want to get the girl, make sure you're wearing the right color.

But first, here's one for the ladies: A few years ago, a study found that men tended to be attracted to women who were wearing red. Participants in the study were shown various pictures of women in different colors. The key was that researchers snuck in more than one photo of certain women wearing different tones. You would think that if the men found a woman to be unattractive in one color, she would be unattractive in any color. Nope. It didn't matter whether the picture of a woman they saw in blue was the same person, only digitally changed to be wearing red. The redder picture was almost always rated as sexier. The men were even willing to spend more money on a date with the women in red than with her counterparts wearing blue, green or gray. Apparently, the people who run red-light districts are smarter than we've been giving them credit for.

As with women's boner-slaying tears, science thinks this has to do with evolution. More specifically with this:

Various types of monkeys and apes have, to put it in scientific terms, hilariously bright-red asses. These serve a purpose other than making humans point and laugh. They tend to swell and get redder when a female is fertile, indicating this fact to the males and thus ensuring the continuation of the species. This relationship of red and fertility may play with a man's perception of what woman he finds most attractive. The monkey in him wants to make sure he knocks someone up, so the suave modern man finds himself most attracted to the lady in red.

A more recent study has found that women are just as susceptible to this phenomenon. Using a similar test of looking at photos, the researchers found that a man wearing red is just as irresistible to a woman. Unlike the evolutionary attraction to a woman in red, researchers say this one is more of a social construct. Women tend to see men wearing red as more powerful, possibly because we associate the color with aggression. Our brains take this to the next level and assume that an aggressive man will be more successful and make more money than a timid one. By wearing red, you project an aura of wealth and potential and sexy. Basically, the only difference between human mating rituals and bullfighting is that human mating rituals didn't give Ernest Hemingway a boner.

4 Your Ear and Forearm

The Romantic Notion:

"When the right person comes along, you'll just know."

Science Says:

The reason your brain might "just know" could simply be a matter of which side of your body the person was standing on when he asked you out. Of course, it's not all that simple. To really improve his chances, he'd have to do something drastic, like touching your arm.

The brain is a really complex organ. But after decades of studying it, most psychologists and neurologists feel comfortable making a couple of generalizations -- namely, that the left side of your brain handles verbal information and is tuned in to positive emotions, while the right hemisphere concentrates on nonverbal stimuli and more negative emotions. They also know that information that goes in your left ear is handled by the right side of the brain.

Armed with this information, psychologists in Italy devised a study that tested how the different sides of your brain process information. What they found is that requests are 50 percent more successful when heard from the right side than the left. In the study, a woman approached people at a club and asked for a cigarette, leaning in to one side or another. Exactly double the number of people obliged her when she asked on their right. In a dating situation, not only could the chances of someone saying yes to a date hinge on who is standing where, but the emotional aspect could come into play as well. Sure, you might agree to go out with someone who talked in your left ear, but your first impression might be to associate him with more negative emotions.

You're even more likely to accept a date if the person asking also touches you on the arm. A French study found that women were more likely to accept an offer to dance with a man at a club, and to give their number to a stranger on the street, if he lightly touched their arm while asking. When questioned about why they said yes, the women who had been touched said they thought the man was more dominant, which might be expected, but they also rated him as more attractive physically.

In addition to proving that French and Italian scientists are exactly as slimy as we'd expect, the studies suggest that standing to someone's right and repeatedly touching that person's arm does the trick. Of course, if you're the sort of person who whispers into a potential partner's ears and lightly touches the person on the arm, you're probably already pretty confident. For the rest of us, just try to keep in mind that a light touch seems to do the trick.

3 The Taste in a Kiss

The Romantic Notion:

"Ah, the kiss, the connection of two souls, the action that binds both young and old lovers for eternity. The romantic tension ... the passion ... the intimacy ... the lust ... the burning desire ... the hunger for more ..."

Science Says:

There's a cluster of chromosomes present in the body called MHC (major histocompatibility complex) that controls part of your immune system. And when you're out looking for someone to breed with, MHC is probably the most influential aspect of a partner that you didn't know you were judging. MHC controls your ability to fight off infection, and if you breed with someone whose MHC is similar to your own, the pregnancy is less likely to take. Finding someone whose MHC is different means a more diverse immune system for the child.

In fact, according to a report in Psychology Today, the scent of MHC might be the second-most-important factor in determining how attractive a woman finds a potential mate. While you might not realize you're secretly judging someone you just met on how well your child would be able to fight off a cold, that's what's happening. Your body tries to instinctively make sure that each potential partner has the sexual compatibility seal of approval. Now how does it do that?

MHC is present in both pheromones and saliva, meaning that to really detect whether a partner is suitable, one must be in close proximity (to smell the MHC), and there must be an exchange in saliva (to taste the MHC). Now, what usually happens when these two events are placed together? That's right, ladies and gentlemen -- the kiss is in fact a goddamn taste test. We've adapted the behavior to make sure we find someone with whom our chemicals match up.

So all that stuff about loving someone's soul? You could go out and find someone who shares your interests, reads the same manga, orders the same pizza, gets along with your parents and even gets the "subtle intelligent humor" that you (and only you) understand. All it would take is the taste of that person's saliva for that interest to go from "I want to make love to you right now! I don't care if the kids I'm babysitting are watching" to "I like you, but more like a brother."

2 The Pill

The Romantic Notion:

"If you truly love someone, know him better than you know yourself and want to spend the rest of your life with him, only then should you get married."

Science Says:

If she's been on birth-control pills the whole time you dated, there's a chance you're both being tricked into marrying exactly the wrong person by your own bodies.

When a woman is actually pregnant, her body decides, "It's not like I can get more pregnant," and it stops doing a bunch of the things it normally does. The pill basically uses hormones to convince a woman's body that it's already pregnant. The woman doesn't want to get pregnant, her body thinks it's pregnant, everyone's happy.

Or at least, they would be if it weren't for that pesky MHC stuff controlling who you can fall in love with. Just as a pregnant woman might find herself suddenly craving food she used to find repulsive, her taste in MHC undergoes a polar reversal. She's no longer attracted to people with MHC that is dissimilar to hers, and way more attracted to men with similar MHC. From an evolutionary perspective, this was probably so that women would want to spend more time around family members in a protective environment rather than out at a bar trying to get laid again. In a modern context, it's probably why pregnant women so often want to murder their husbands with a meat cleaver: He no longer smells like her type, and it's far too late for that.

A woman on the pill gets exactly the same effect, without the belly or the appearance of the boob fairy. For the entire time she's on the pill, a woman will prefer people with MHC that is similar to her own. This is why some psychologists believe that the high divorce rate in modern times can be blamed on the pill. Two people can be dating for years, thinking they're meant for each other when in reality, their MHC is the exact opposite of compatible. Of course, they only find out when they're ready to hatch one and she goes off the pill, which of course is often way, way too late.

1 Timing

The Romantic Notion:

"It's OK, Jimmy -- you don't have to talk to her now. Whenever you get the courage, whenever fate and destiny decide, that's the right time."

Science Says:

Whether you end up getting rejected by someone or falling in love with her can be totally determined by the day of the month you meet her.

Whether a woman wants babies or not, her body definitely does. Every month, a woman's body fires up the baby maker, releasing a fertile egg into the line of fire in case she gets lucky. To help improve her luck, her body also makes sure she looks ripe for the picking by raising the size of her breasts, dilating her pupils and increasing the pitch of her voice. All of this is accompanied by a cocktail of pheromones wafting off her body into the air around her.

Yes, there is a time every month that each woman is basically signaling to the world that she wants to have sex. How good are men at picking up on these signals? One study showed "that strippers who are ovulating average $70 in tips per hour, those who are menstruating and thus unable to conceive make $35 and those who are doing neither make $50." Women have also reported "that when they're ovulating, their partners are more loving and attentive and, significantly, more jealous of other men."

This means that women who meet Mr. Wrong during ovulation are more likely to sleep with him, and he's less likely to say no. So if Romeo and Juliet had met two weeks earlier, there's a pretty good chance the play would have been called The Capulets Throw an Uneventful Party.

So ladies, if you're wondering how you keep ending up with jerks, take a look back through your inbox. Do the emails you send your friends about how you "met the greatest guy at the bar last night" tend to fall around the same time each month? It might be because ovulation actually lowers women's standards for sexual partners and even goes so far as to increase their likelihood of sex with multiple partners.

And guys, if a douchebag runs into your dream girl at a sexually convenient time, it might not even matter if he's the type of person who would request a "bridesmaid sandwich" in their wedding vows. He's going to have the edge.

Sami would like to thank Andrew, Kadir and Matt for their inadvertent assistance; Mark M. freelances and dispenses bad philosophy and relationship advice. Follow Kathy on Twitter, befriend her on Facebook or read the rest of her Cracked articles here.

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