When You Feel "Chemistry" With Someone, What's Actually Going On?

iStock
iStock

We know chemistry when we feel it with another person, but we don't always know why we're drawn to one person over another. Is it just a cascade of neurotransmitters and hormones conspiring to rush you toward reproduction? Is it attraction borne of a set of shared values? Or is it bonding over specific experiences that create intimacy?

It's probably a combination of all three, plus ineffable qualities that even matchmaking services can't perfectly nail down.

"Scientists now assume, with very few exceptions, that any behavior has features of both genetics and history. It's nature and nurture," Nicole Prause, a sexual psychophysiologist and neuroscientist, tells Mental Floss. She is the founder of Liberos, a Los Angeles-based independent research center that works in collaboration with the University of Georgia and the University of Pittsburgh to study human sexual behavior and develop sexuality-related biotechnology.

Scientists who study attraction take into consideration everything from genetics, psychology, and family history to traumas, which have been shown to impact a person's ability to bond or feel desire.

THE (BRAIN) CHEMISTRY OF LOVE

Helen Fisher, a biological anthropologist at Rutgers University, Match.com's science advisor, and the author of Anatomy of Love: A Natural History of Mating, Marriage, and Why We Stray, breaks down "love" into three distinct stages: lust, attraction, and attachment. In each stage, your body chemistry behaves differently. It turns out that "chemistry" is, at least in part, actual chemistry. Biochemistry, specifically.

In the lust and attraction phases, your body is directing the show, as people can feel desire without knowing anything personal about the object of that desire. Lust, Fisher asserts in a seminal 1997 paper [PDF], is nothing more than the existence of a sex drive, or "the craving for sexual gratification," she writes. It's a sensation driven by estrogens and androgens, the female and male sex hormones, based in the biological drive to reproduce.

Attraction may be influenced less than lust by physiological factors—the appeal of someone's features, or the way they make you laugh—but your body is still calling the shots at this stage, pumping you full of the hormones cortisol, adrenaline, and dopamine, effecting your brain in a way that's not unlike the way illicit substances do.

Fisher has collaborated multiple times on the science of attraction with social psychologist Arthur Aron, a research professor at Stony Brook University in New York. Aron and his wife Elaine, who is also a psychologist, are known for studying what makes relationships begin—and last.

In a 2016 study in Frontiers in Psychology, the researchers proposed that "romantic love is a natural (and often positive) addiction that evolved from mammalian antecedents by 4 million years ago as a survival mechanism to encourage hominin pair-bonding and reproduction, seen cross-culturally today."

In the attraction phase, your body produces increased amounts of dopamine, the feel-good chemical that is also responsible for pain relief. Using fMRI brain imaging, Aron's studies have shown that "if you're thinking about a person you're intensely in love with, your brain activates the dopamine reward system, which is the same system that responds to cocaine," he tells Mental Floss.

Earlier, Fisher's 1997 paper found that new couples often show "increased energy, less need for sleep or food, focused attention and exquisite delight in smallest details of this novel relationship."

The attachment phase is characterized by increases in oxytocin and vasopressin; these hormones are thought to promote bonding and positive social behaviors to sustain connections over time in order to fulfill parental duties.

There is no hard and fast timeline for how long each phase lasts, as it can vary widely due to gender, age, and other environmental factors, Fisher writes.

Additionally, while oxytocin has long gotten the credit for being the love hormone, Prause says that scientists are now "kind of over oxytocin," because it has broader functions than simply bonding. It also plays a role in the contraction of the uterus to stimulate birth, instigating lactation, and sexual arousal; low levels have been linked to autism spectrum disorders. 

Now they're focusing on a charmingly named hormone known as kisspeptin (no, really). Produced in the hypothalamus, kisspeptin plays a role in the onset of puberty, and may increase libido, regulate the gonadal steroids that fuel the sex drive, and help the body maintain pregnancy. But Prause says there is a lot more study about the role kisspeptin plays in attraction.

CHEMICAL AND PERSONAL BONDS

Biology may explain our initial attraction and the "honeymoon" phase of a relationship, but it doesn't necessarily explain why a person's love of obscure movies or joy of hiking tickles your fancy, or what makes you want to settle down.

The Arons' numerous studies on this subject have found connection boils down to something quite simple: "What makes people attracted to the point of falling in love—presuming the person is reasonably appropriate for them—is that they feel the other person likes them," he says. 

In the process of doing research for her book How To Fall in Love With Anyone, writer Mandy Len Catron of Vancouver became her own test subject when she came across the research the Arons are most well-known for: their 36 questions, which promote bonding.

The questions were originally designed to "generate intimacy, a sense of feeling similar, and the sense that the other person likes you," Aron explains. Romantic love wasn't the goal. "It was a way of creating closeness between strangers."

The Arons first tested their questions by pairing up students during a regular class section of a large psychology course, as they related in a paper in the journal Personality and Social Psychology Bulletin. Some students were paired with someone of the same sex, while others were matched with someone of the opposite sex. Each partner then answered a series of 36 increasingly personal questions, which took about 45 minutes each. (Question 2: "Would you like to be famous? In what way?" Question 35: "Of all the people in your family, whose death would you find most disturbing? Why?") Small talk during class hadn't made them bond, but the questions made the students feel closer.

In another version of the study, heterosexual, opposite-sex pairs follow the 36-question session with four minutes of staring deeply into each other's eyes.

Catron decided to test these methods out with a casual acquaintance, Mark, over beers at a local bar one night. They were both dating other people at the time, and no one exclusively. As she answered the questions and listened to Mark's answers, "I felt totally absorbed by the conversation in a way that was unlike any of the other first dates I was having at the time with people I met online," Catron tells Mental Floss.

She was ready to skip the four minutes of soulful eye gazing, but Mark thought they should try it. "It was deeply uncomfortable, but it was also an important part of the experience," she recalls. "It's so intimate, it requires you to let your guard down."

The process instilled in Catron a deep feeling of trust in Mark and a desire to know him better. Within three months, they began dating in earnest. Now, more than three years later, they live together in a condo they bought.

The Arons' questions offer "accelerated intimacy," she says, in a time of increasingly online-driven dating experiences.

A LITTLE MYSTERY, A LOT OF SHARED VALUES

Despite all that we’ve learned, scientists may only ever be able to brush up against the edge of a true understanding of "chemistry." “We understand a fair amount about what happens when [attraction has] already occurred, but we're really bad at predicting when it will happen," Prause says. "People who try to claim magical matchmaking, or that they're going to somehow chemically manipulate an aphrodisiac or something—well good luck! Because we can't figure it out.”

And anyway, what's romance without a little mystery?

If you must have a definitive answer to the puzzle of interpersonal chemistry, Prause says to keep this in mind: "The best predictor of long-term outcomes is shared values."

This piece originally ran in 2018.

12 Intriguing Facts About the Intestines

When we talk about the belly, gut, or bowels, what we're really talking about are the intestines—long, hollow, coiled tubes that comprise a major part of the digestive tract, running from the stomach to the anus. The intestines begin with the small intestine, divided into three parts whimsically named the duodenum, jejunum, and ileum, which absorb most of the nutrients from what we eat and drink. Food then moves into the large intestine, or colon, which absorbs water from the digested food and expels it into the rectum. That's when sensitive nerves in your rectum create the sensation of needing to poop.

These organs can be the source of intestinal pain, such as in irritable bowel syndrome, but they can also support microbes that are beneficial to your overall health. Here are some more facts about your intestines.

1. The intestines were named by medieval anatomists.

Medieval anatomists had a pretty good understanding of the physiology of the gut, and are the ones who gave the intestinal sections their names, which are still used today in modern anatomy. When they weren't moralizing about the organs, they got metaphorical about them. In 1535, the Spanish doctor Andrés Laguna noted that because the intestines "carry the chyle and all the excrement through the entire region of the stomach as if through the Ocean Sea," they could be likened to "those tall ships which as soon as they have crossed the ocean come to Rouen with their cargoes on their way to Paris but transfer their cargoes at Rouen into small boats for the last stage of the journey up the Seine."

2. Leonardo da Vinci believed the intestines helped you breathe.

Leonardo mistakenly believed the digestive system aided respiratory function. In 1490, he wrote in his unpublished notebooks, "The compressed intestines with the condensed air which is generated in them, thrust the diaphragm upwards; the diaphragm compresses the lungs and expresses the air." While that isn't anatomically accurate, it is true that the opening of the lungs is helped by the relaxation of stomach muscles, which does draw down the diaphragm.

3. Your intestines could cover two tennis courts ...

Your intestines take up a whole lot of square footage inside you. "The surface area of the intestines, if laid out flat, would cover two tennis courts," Colby Zaph, a professor of immunology in the department of biochemistry and molecular biology at Melbourne's Monash University, tells Mental Floss. The small intestine alone is about 20 feet long, and the large intestine about 5 feet long.

4. ... and they're pretty athletic.

The process of moving food through your intestines requires a wave-like pattern of muscular action, known as peristalsis, which you can see in action during surgery in this YouTube video.

5. Your intestines can fold like a telescope—but that's not something you want to happen.

Intussusception is the name of a condition where a part of your intestine folds in on itself, usually between the lower part of the small intestine and the beginning of the large intestine. It often presents as severe intestinal pain and requires immediate medical attention. It's very rare, and in children may be related to a viral infection. In adults, it's more commonly a symptom of an abnormal growth or polyp.

6. Intestines are very discriminating.

"The intestines have to discriminate between good things—food, water, vitamins, good bacteria—and bad things, such as infectious organisms like viruses, parasites and bad bacteria," Zaph says. Researchers don't entirely know how the intestines do this. Zaph says that while your intestines are designed to keep dangerous bacteria contained, infectious microbes can sometimes penetrate your immune system through your intestines.

7. The small intestine is covered in "fingers" ...

The lining of the small intestine is blanketed in tiny finger-like protrusions known as villi. These villi are then covered in even tinier protrusions called microvilli, which help capture food particles to absorb nutrients, and move food on to the large intestine.

8. ... And you can't live without it.

Your small intestine "is the sole point of food and water absorption," Zaph says. Without it, "you'd have to be fed through the blood."

9. The intestines house your microbiome. 

The microbiome is made up of all kinds of microorganisms, including bacteria, viruses, fungi, and protozoans, "and probably used to include worm parasites too," says Zaph. So in a way, he adds, "we are constantly infected with something, but it [can be] helpful, not harmful."

10. Intestines are sensitive to change.

Zaph says that many factors change the composition of the microbiome, including antibiotics, foods we eat, stress, and infections. But in general, most people's microbiomes return to a stable state after these events. "The microbiome composition is different between people and affected by diseases. But we still don't know whether the different microbiomes cause disease, or are a result in the development of disease," he says.

11. Transferring bacteria from one gut to another can transfer disease—or maybe cure it.

"Studies in mice show that transplanting microbes from obese mice can transfer obesity to thin mice," Zaph says. But transplanting microbes from healthy people into sick people can be a powerful treatment for some intestinal infections, like that of the bacteria Clostridium difficile, he adds. Research is pouring out on how the microbiome affects various diseases, including multiple sclerosis, Parkinson's, and even autism.

12. The microbes in your intestines might influence how you respond to medical treatments.

Some people don't respond to cancer drugs as effectively as others, Zaph says. "One reason is that different microbiomes can metabolize the drugs differently." This has huge ramifications for chemotherapy and new cancer treatments called checkpoint inhibitors. As scientists learn more about how different bacteria metabolize drugs, they could possibly improve how effective existing cancer treatments are.

This 3D-Printed Sushi is Customized For You Based on the Biological Sample You Send In

Open Meals
Open Meals

Many high-end restaurants require guests to make a reservation before they dine. At Sushi Singularity in Tokyo, diners will be asked to send fecal samples to achieve the ideal experience. As designboom reports, the new sushi restaurant from Open Meals creates custom sushi recipes to fit each customer's nutritional needs.

Open Meals is known for its experimental food projects, like the "sushi teleportation" concept, which has robotic arms serving up sushi in the form of 3D-printed cubes. This upcoming venture takes the idea of a futuristic sushi restaurant to new extremes.

Guests who plan on dining at Sushi Singularity will receive a health test kit in the mail, with vials for collecting biological materials like urine, saliva, and feces. After the kit is sent back to the sushi restaurant, the customer's genome and nutritional status will be analyzed and made into a "Health ID." Using that information, Sushi Singularity builds personalized sushi recipes, optimizing ingredients with the nutrients the guest needs most. The restaurant uses a machine to inject raw vitamins and minerals directly into the food.

To make things even more dystopian, all the sushi at Sushi Singularity will be produced by a 3D-printer with giant robotic arms. The menu items make the most of the technology; a cell-cultured tuna in a lattice structure, powdered uni hardened with a CO2 laser, and a highly detailed model of a Japanese castle made from flash-frozen squid are a few of the sushi concepts Open Meals has shared.

The company plans to launch Sushi Singularity in Tokyo some time in 2020. Theirs won't be the first sushi robots to roll out in Japan: The food delivery service Ride On Express debuted sushi delivery robots in the country in 2017.

[h/t designboom]

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