Do You Believe in Love at First Sight? The Science of Love & First Impressions.
Exploring the Chemistry of Love: How First Impressions Shape Romantic Attraction
This is an old article I wrote a few years ago. I updated it a bit and, since The Science of Sex has gained thousands of subscribers over the past year, I’m re-publishing it for those who missed it the first time around. It was one of my favorites, both to research and write, and I think a lot of you will enjoy it.
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His eyes opened wide as he saw a vague figure approaching him.
He stood out in front of an apartment complex, waiting for his date. It was a traditional date—Tinder wasn’t yet the monolithic dating app it’s become today, so the two met beneath the shopping mall's bright, beaming white lights.
They’d texted for a while until he finally worked up the courage to ask. After some fun and witty banter, the two set a date. Saturday night. They’d meet in front of his house.
The date was to be a bookstore and record shop combined into one. Nothing like dusty old books and niche vinyl to spark up conversations. Such dates, he believed, were far superior to the stuffy atmospheres of fancy restaurants or the fully-internal experience of a movie next to someone you barely know.
There he was, standing outside on an early-summer evening just after sunset, anxiously awaiting the woman he’d set his sights on.
As the figure marched closer, his brain began to interpret the shape of a woman. He felt a sudden pounding in his chest. His palms began to sweat. He’s tense, wondering how smoothly his date would go.
Epinephrine and cortisol levels spike in his body.
His stress response kicks into high gear.
He might as well have been trying to outrun a ferocious lioness across the grassy plains of Africa.
The figure came closer.
“Hey,” he says in the calmest voice he can muster through the exciting terror in his nervous system.
“Hey!” she piped up, her high pitch signaling her own excitement. She comes close and stands within a foot of him.
For a few seconds, the two lock eyes. They observe each other with outsized smiles, taking in one another’s essence. Their brains accelerate and start processing information at an outstandingly high pace.
It’s a classic case of love at first sight.
It’s as if they were just injected with amphetamine, their hearts raging on, beating to the sound of unheard drums.
This is Your Brain on (Love) Drugs
You might’ve heard that falling in love is like being on stimulants like cocaine or amphetamine. Medical News Daily penned an article Falling in Love Hits The Brain Like Cocaine. This is misleading.
They mention the usual suspects: oxytocin, dopamine, vasopressin, and adrenaline. These everyday neurotransmitters are released in various situations, from running to eating and exercising in the gym.
They pale compared to the real love drug: phenylethylamine (PEA). It’s the real Love Potion #9. PEA is a stimulant released in massive quantities when we fall in love.
Phenylethylamine is sold legally as a drug on the supplement market (here on Amazon), and it’s highly effective but…it only lasts about five minutes (I’ve tried it).
As the two people begin their date, their eyes scan one another’s bodies, especially their faces.
Neither of them knows it yet, but at this point, the two have mostly made up their minds about one another. Much of the process of attraction was unconscious. It happened in the blink of an eye.
Her blithe disposition allowed him to let his guard down a bit. The two embraced in a hug that was foreign but welcome, their hearts warmed by one another’s touch.
The Numbers of Love
People call it “chemistry.” It’s this beautiful squishy flesh machine, this three pounds of gray matter housed in our skulls, that we call the brain doing what it does best: processing and interpreting its environment, looking for cues of threat and friendship.
We have five senses, but we’ve evolved to rely on one above the rest: the sense of sight.
Researchers at the University of Pennsylvania determined how much information the eye could take in and transmit to the brain with experiments on guinea pigs—ten million bits per second.
The human eye takes in ten times that amount.
On their first date, our lovebirds observe one another with far greater clarity than your average guinea pig. Their eyes see 54 megapixels, roughly 4.5 times more than the camera on an iPhone 14.
And we see in at least thirty frames per second, possibly much more than that. Some research has found that the human eye can see between 50 and 90 frames per second.
If you ever think your smartphone is impressive, realize that the human eye takes in more information than the operating system software in just a few seconds.
Rodrigo Quian Quiroga, the author of The Forgetting Machine, crunched the numbers from this information and found that our eyes absorb 4.8 GB of data every single second. That’s 57.6 GB of information per day.
That means your eyes see the equivalent of 1,329.6 photos taken with your 12-megapixel smartphone camera every single second. The average smartphone user takes 20.2 pictures per day. It would take them nine weeks to take as many photos as the eye sees in a single second.
Your brain could fill up a one-terabyte hard drive in only 2.5 weeks.
And as they look at each other, they make instantaneous judgments. It all happens so incredibly fast.
People who disbelieve in the possibility of romantic love at first sight might change their tune if they heard the science.
The Speed of Love
All that information the eye takes in gets transmitted to the brain at about 10 Mbps, as fast as your high-speed internet.
Research by Lindgaard et al. has shown that it only takes 50 milliseconds, 1/20th of one second, to judge whether something is aesthetically pleasing. Scary, I know, but it’s not the whole story. We’ve got a long way to go and a lot to clarify.
Within 1/20th of a second, the two people know whether they’re attracted to one another.
They've summed one another up not even 1/10th of a second into this first date. According to research from Princeton University, that’s how long it takes humans to judge someone’s face.
Tracing the Lines of Beauty
Our lovebirds head to the car and start driving to the record store, where they occasionally glance at one another’s faces for a gaze. And though they see the other person’s face, their eyes are doing something fascinating.
Like the facial recognition technology that unlocks your smartphone, the human eye scans things by pinpointing the most critical information. It doesn’t just take in a flat image of everything it seems; it hones on the parts that matter most.
In the 1960s, Russian researcher Alfred Yarbus used eye-tracking technology to figure out how this works. We scan a few data points, and our brains fill in the rest, making assumptions as we go along.
Our lovers are tracing lines across one another’s faces, unconsciously measuring jawlines, brow ridges, cheekbones, and symmetry.
And they’re doing the same. He scans the various points across her face as she picks up a Radiohead record. She turns and does the same. They don’t need to see an entire face to decide whether they find each other attractive. They need a few key points.
This photo of a woman doesn’t even give us a full face. And though 52% of what we find attractive is individual rather than universal, many people would say this woman is attractive without even seeing her eyes.
We’re particularly good at summing up people’s faces.
Much of this process is innate. We’re born with it.
Back at the record shop, the date progresses. The woman’s mind begins to wander. She starts thinking about the traits she wants most in a partner.
What does she imagine? Is her imaginary perfect stud created from her choices, wants, and desires? Or does she like what she likes just because that’s what cultural messages have told her she should value her whole life, and she’s never imagined something different?
Fortunately, science has some answers.
Universal and Individual Attraction
One constant throughout the science of human attraction is that people usually prefer symmetrical faces.
We like familiarity and averageness, and we unconsciously perceive these things as signaling a healthy immune system better capable of fighting off nasty parasites that might kill any children we have.
Studies suggest infants as young as four months old can discern an “attractive” face (obviously not in a romantic way). Surprisingly, infants are usually attracted to the same faces adults are in studies.
The infants’ judgments about faces aligned with what adults consider attractive. Infants didn’t care about vertical symmetry (top to bottom) but horizontal symmetry (side to side). Infants also didn’t care much about averages and even preferred non-average-looking faces.
These are the universals. But not all attraction is universal. As mentioned above, research suggests that 52% of attraction is individual and only 48% is universal.
If you took two people and asked them to point attractive people out of a crowd, they’d agree 48% of the time, and they’d disagree 52% of the time.
Some traits are universally attractive across cultures, while others differ between cultures and even within the same culture.
Women are more likely to disagree on what they think is attractive, and men are more likely to agree. Men generally find the same “types” beautiful, while women are more varied in what they find attractive.
People judge women more harshly than men regarding looks, beauty, and body size, but women are the harshest judges — men are much more forgiving.
Attraction is also shaped more by our environment than by our genes.
Studies have shown that environment influences 78% of what people find attractive, while genes influence 22%.
Of Conscious & Unconscious Attraction
On the way home from their date, they both silently think things went incredibly well. She hopes he’ll invite her up to his apartment for more time together. He’s working up the courage to do so.
As they think, a lot of unconscious processes are at work. Her eyes have been drawn to his colorful shirt all night. We’re unconsciously drawn to bright colors, so consider this the next time you have a hot date.
His eyes scan her hips and gaze at her breasts in hopes of informing him about her “reproductive fitness,” which is just science speak for “how badly he wants to see her naked.”
When we meet someone for the first time, our brains light up like fireworks. Three dedicated parts activate. They all affect how we feel about our perceptions: the amygdala, the posterior cingulate cortex, and the thalamus.
All three of these parts live in the limbic system of our brains — a system that plays a decisive role in forming our emotions, long-term memories, sense of smell, and regulating behavior. What we see when we meet someone creates an impression on us — an emotional feeling that we don’t “think” but “feel.”
Do you know that “feeling” you get around certain people you can’t explain?
That’s your limbic system.
The limbic system detects all the little details about a person and pieces them together, giving us a general feeling about someone. And since the limbic system plays such a decisive role in forming our emotions, we “sense” things about a person we can’t quite put our fingers on.
This all happens under the radar, without so much as a conscious thought.
But the two also make conscious assumptions based on what they see. He sees big smiles and bright eyes as a cue that she might be open to spending more time with him and decides to ask her.
Without hesitation, she agrees, thrilled that he asked.
Judging by his hair, clothing, and belt matching his shoes, she makes other assumptions about his hygiene. We can’t help but make such assumptions.
She assumes his apartment will be spotless, and when they arrive through the front door, she finds out that she was correct. If we operate on the premise that people put their best foot forward and show the best sides of themselves on a first date, it’s safe to assume it’s all downhill from there.
If his hair is an unkempt mess, his shirt is wrinkled and has been worn for three days without being washed, and his shoes are untied, she would naturally make other conscious assumptions about his life based on these facts.
Pro-tip: always put your best foot forward, especially on first dates. People are making conscious and unconscious judgments. Neither is within your control, and only one is in the other person’s control.
Adding all this up, the science makes a compelling case for the age-old question: is love at first sight real?
Considering how well we evolved to sum up situations in a split second efficiently, it’s safe to say that it’s possible, even probable, if by “love” we mean romantic love, a deep, inexplicably strong attraction for someone.
The date was a huge success. She and I went up to my apartment, we talked for a few hours, and my nervousness was gone by the time we reached the record store. Thankfully, my place was spotless.
And wouldn’t you know it? We even kissed before she went home, and we both went to bed with butterflies in our stomachs, anxiously anticipating our next meeting.
I'd refer you and your readers here:
https://loveandmarriage.substack.com/p/love-is-a-verb
Of all the misconceptions about love, the most powerful (and pervasive) is the belief that "falling in love" is love -- or at least a manifestation of love. It is a potent misconception, because falling in love is subjectively experienced, in a very powerful way, as an experience of love. When a person falls in love what they feel is:
"I love this person."
The experience of "falling in love" is specifically a sex-linked experience.
We do not fall in love with our children or our parents, even though we may love them very deeply.
We do not fall in love with our friends, even though we may care for them very much.
We fall in love only when we are sexually motivated, whether consciously or unconsciously.
Falling in love is not an act of will, as it is not a conscious choice. No matter how open to it, or eager for it, we may be -- the experience may still elude us.
The experience may capture us at times when we are definitely not seeking it, when it is inconvenient and even undesirable.
We are as likely to fall in love with someone with whom we are obviously ill-matched, as with someone more suitable. Discipline and will can only control the experience; they cannot create it. We can choose how to respond to the experience of falling in love, but we cannot choose the experience itself.
The experience of falling in love is invariably, and always, temporary. No matter with whom we fall in love, we sooner or later fall "out" of love. That feeling of lovingness that characterizes the experience of falling in love always passes. The honeymoon always ends. The bliss of romance always fades.
Excellent post. You may want to read Wired for Love by Stephanie Cacciopo for even more on this. And I wrote a short post "Biological Fireworks" in The Pleasure Principle on the physical aspect of falling in love, which fascinates me.