Why We Click
The Emerging Science of Interpersonal Synchrony
By Kate Murphy
Category: Psychology | Reading Duration: 20 min
About the Book
Why We Click (2026) reveals the hidden science of interpersonal synchrony – the unconscious process where our bodies align with others through matching heart rates, movements, and neural patterns – explaining why some people energize us while others leave us exhausted. By understanding this powerful phenomenon, we can learn to foster beneficial connections that enhance our wellbeing while protecting ourselves from draining interactions that threaten our sense of self.
Who Should Read This?
- Parents who want to cultivate their child’s capacity for connection
- Romantics who want to understand the invisible forces that shape personal chemistry
- Team leaders who want to deploy interpersonal synchrony to boost morale
What’s in it for me? The science of personal connection.
Interpersonal synchrony: it might just be the most consequential social dynamic you’ve never heard of. If you’ve ever instantly clicked with someone, felt your eyes drawn to a stranger across a crowded room, experienced attraction or irritation at first sight, cringed at someone's embarrassment as if it were your own, or felt euphoric oneness singing in a choir, then you’ve experienced interpersonal synchrony. So what is it exactly? In short, it’s the phenomenon where our bodies and minds align with others.
It describes the way our heart rates, breathing patterns, hormones, muscle tension, and neural oscillations harmonize or clash during interactions with others. We rarely notice it happening in the moment. Later, we construct explanations for why we liked or disliked someone, unaware our reactions stem from synchronized physiological activity during the encounter – or the uncomfortable absence of it. Understanding this hidden mechanism reveals why we click with some people instantly, and why others inexplicably leave us cold. In this Blink we’ll dig deeper into the science and sociology of exactly why and how we click.
Chapter 1: We learn interpersonal synchrony from birth
Meet two neighbors: Joan and Jen. Both are octogenarians who take daily walks through the neighborhood, but the reactions they inspire couldn't be more different. Joan seems to light up everyone she encounters. Sulky schoolchildren perk up at her smile.
Dog walkers glued to their phones suddenly look up and chat. There's something about her presence that makes people feel good. Jen creates the opposite effect. Watch people around her carefully: they cross their arms and shift uncomfortably. Their brows furrow. Some neighbors have admitted they hide behind bushes when they see her coming, unable to articulate why interactions with her feel exhausting.
What accounts for this stark difference? The answer lies in something called interpersonal synchrony – the invisible dance of heart rates, breathing patterns, hormones, muscle tension, and neural activity that either harmonizes between people or clashes. When we interact with someone, our bodies are constantly trying to tune into each other like instruments in an orchestra. With Joan, the music flows. With Jen, it grates. This synchrony begins forming from birth.
A mother instinctively cradles her newborn on her left side, close to her heart, which synchronizes their cardiac rhythms. The position also ensures the baby's right brain hemisphere, where emotional processing happens, is perfectly angled to read her facial expressions. As she rocks, coos, and makes exaggerated faces, she's doing more than soothing her child. She's literally calibrating the baby's nervous system for human connection. Fathers tend to contribute something different but equally important. While mothers often create calming, predictable rhythms, fathers roughhouse and play in ways that spike arousal and create syncopated beats.
Together, these contrasting rhythms teach infants to synchronize at different tempos, preparing them for navigating varied social landscapes. What happens when this early synchrony never develops? Neuroscientist Ruth Feldman has tracked children from infancy into young adulthood, and her findings are sobering. Babies who missed synchronized interactions show significantly reduced activity decades later in the brain regions responsible for empathy and connection.
Mentors or romantic partners can activate these networks later in life, but it's an uphill battle, like trying to learn a language after childhood has passed. We are, from our first breath, creatures built to sync with one another. Joan and Jen stand as proof of what happens when this system works well or breaks down.
Chapter 2: Synchronization at first sight
Speed dating might feel modern, but it has Victorian roots. Every New Year's Day in nineteenth-century high society, eligible bachelors made round-robin calls at the homes of marriageable young ladies. Five minutes maximum per visit – place your engraved calling card on the butler's silver tray, discuss the weather, sip some punch, maybe grab an oyster before moving to the next house. One gentleman logged 107 houses in a single day back in 1866.
Turns out five minutes was plenty. Research shows we decide whether we're interested in someone in under thirty seconds, and we're often more accurate at gauging connection in these brief exposures than when given time to deliberate. So what actually happens in those crucial moments? For nearly twenty years, researchers tried to find out. They ran speed-dating experiments everywhere from laboratories to music festivals, initially finding confounding results. People picked partners outside their stated preferences.
Physical attractiveness didn't guarantee success. How animated someone was or what they said also proved an unreliable predictor. Then came the breakthrough: new technology that could reveal what was really happening. With laser motion sensors, eye-tracking smart glasses, and brain hyperscanning that records multiple people simultaneously, researchers learned that couples who clicked were literally on the same wavelength. Their microexpressions mirrored unconsciously, including tiny twitches around eyes and mouths they couldn't see or fake. Speech patterns synchronized – not just words but tonality, pitch, and even how they structured sentences and used function words.
Deeper still, heart rates coupled, respiration matched, brain waves aligned, skin conductance synced. Chemistry isn't metaphorical. It's measurable physiology. This explains why dating apps, despite their swiping efficiency, increasingly disappoint. Many users report not feeling it online, or finding their virtual connection fades to disappointment in person. True synchrony demands physical presence.
It demands living breathing bodies calibrating to each other in real time. Once established, synchrony deepens over time. Couples who sync better recognize each other's emotions, particularly distress, and report higher relationship satisfaction. The process is dynamic and ongoing: partners co-regulate moment by moment, one accelerating while the other soothes, reaching equilibrium together. During mutually satisfying sex, both partners tune in physically, emotionally, and hormonally, each building excitement that stokes the other's until climax and calm. A supportive partner's mere presence slows an anxious partner's heart rate and lessens physical pain, especially when holding hands.
This biobehavioral balancing is why we seek loved ones when distressed. Their presence returns us to baseline, our bodies and emotions intertwined. When Sarah joined the marketing team at a mid-sized tech firm, colleagues noticed something unsettling. Meetings she attended grew tense.
Chapter 3: When synchronization goes wrong
Her fixed stare and crossed arms signaled disapproval before anyone spoke. Within months, the once-collaborative team fractured. Two junior staffers who sat near her began mirroring her negativity, shooting down proposals in unison. Creative meetings became exercises in deflection.
Sarah exerted what psychologists call the bad apple effect – one person's negativity poisoning an entire group. But how powerful is one person's vibe, really? Researcher Noah Eisenkraft set out to quantify what he calls affective presence – the consistent effect someone has on how others feel. He studied 239 MBA students assigned to learning teams, deliberately choosing a setup where students couldn't self-select based on who made them feel good. After all, in workplaces, as in families, we typically don't get to choose our teammates. Using sophisticated variance partitioning, Eisenkraft isolated each person's affective presence while controlling for their own personality traits and the unique chemistry that might develop between any two individuals.
The findings were striking. Someone else's bad vibe affects your mood even more than your own personality does. Negative affective presence accounted for 23 percent of how badly people felt, while their own temperament accounted for just 19 percent. Positive presence had a smaller but still significant impact – which makes sense, as Eisenkraft noted. After all, it's easier to recall people who make you angry than people who make you happy. Eisenkraft saw these patterns repeatedly in his consulting work.
Two executives, same rank, same background, managing similar crises. Both competent, both stressed. But one metabolized his stress internally while the other radiated it outward. Same conversations, entirely different tenor in the room. When the crises ended, one team fought to stay together while the other sought escape – not because they disliked their leader, but because showing up to work simply felt harder. The bad apple effect reveals synchrony's power and peril.
We evolved to sync because it bonds us, coordinates us, connects us. But that same mechanism can make us absorb others' emotional states more powerfully than our own personalities shape us. Understanding affective presence means recognizing that other people's vibes aren't abstract qualities we passively notice – they're forces actively reshaping our inner landscape, for better or worse.
Chapter 4: Interoception is your secret superpower
It's the late 1960s at Massachusetts Mental Health Center in Boston. The auditorium is packed. On stage, two men converse like old friends. Except one is severely psychotic – and he's speaking rationally, reasonably, lucidly.
The audience is riveted. Dr. Elvin Semrad, the hospital's legendary clinical director, has done it again – connecting with a patient thought too far gone. Semrad's secret was masterful interpersonal synchrony. During case conferences, he'd have patients describe where physically they were holding their feelings. Tightness in the shoulders?
Heaviness in the chest? Butterflies in the stomach? He was teaching interoception: the ability to sense your internal physiological state. By reintroducing patients to their bodies, he helped them acknowledge discomfort that was alienating them from themselves. When patients returned to their bodies and felt what they were feeling, they could sync comfortably with Semrad, whose kind presence calmed them. This matters because emotions aren't abstract concepts in your brain.
They're bodily sensations your brain interprets as feelings. Your body's trillions of oscillatory cells falling into and out of synchrony with one another, and with rhythms from the outside world, are what your brain construes as emotions. Those interpretations, accurate or not, determine everything you do. People who score higher on interoception tests – accurately counting heartbeats, precisely reporting when fluid hits their bladder – sync more easily with others and interpret emotions more accurately. One study of high-frequency traders at a London hedge fund found those with better interoception made more money and stayed on the job longer. People with good interoception are more resilient in challenging social situations and make sounder financial decisions.
We can only read what's going on with others to the degree we read what's going on within ourselves. Empathy arises from embodying another's feelings. But it breaks down if you're insensitive to signals within your own body.
Chapter 5: Too much of a good thing
Like oxygen or water, interpersonal synchrony follows a Goldilocks principle: too little leaves you isolated and lonely, too much threatens your sense of self. Over-syncing – what psychologists call emotional fusion or enmeshment – creates engulfing relationships where feelings, attitudes, and behaviors become unhealthily intertwined. The telltale sign? Relationships that are reaction rich.
Partners react immediately and reflexively to any perceived deviation or distance, either matching the other person's affective energy or trying to pull them into their own. There's often a feeling of responsibility for the other's feelings because, in fact, those feelings feel like your own. An innovative study using whole-body imaging demonstrated the problem. Researchers had subjects engage in wordless body conversations and found an inverse relationship between interpersonal synchrony and emotional regulation. While synchrony predicted positive feelings, it also made people feel less in control of their emotions. Conversely, the more subjects tuned into their own movements, the more they regulated their emotions.
To maintain a stable self, people need moments of independence and disengagement. This applies beyond close relationships. At parties or networking events, people become amped-up versions of themselves, anxious to impress. Without realizing it, you might match their wide-eyed urgency, exaggerated expressions, and louder vocal range. Or you might absorb someone's social discomfort and feel rattled yourself. No wonder people reach for drinks at these gatherings.
You can de-sync and reclaim yourself by simply recognizing when this kind of flash fusion is happening. Deepen your breathing, relax tension, adjust your posture, slow your speech cadence. You'll feel less drained – and incredibly, the other person often relaxes too. Think of it as “energy hygiene” – scrubbing yourself of emotional residue between interactions. It's about managing and regulating your energy because it's contagious. The balance is everything: connect deeply to communicate, relate, and love – but maintain enough independence to self-reflect, self-regulate, and remain authentically yourself.
Chapter 6: What’s stealing your sync?
More than half of Americans – roughly 180 million people – report feeling disconnected and lonely. But loneliness isn't a disease. It's a biological signal, like thirst or hunger, alerting you that a critical need isn't being met. You're out of sync with society, either from spending too much time alone or feeling disconnected from those around you.
So who stole our sync? Technology plays a role, but the larger culprit is the frictionless economy. Corporations have systematically eliminated what they call pain points – those small interactions that once peppered our days. Order coffee through an app, skip the barista. Use a virtual assistant, skip the app entirely. Install a smart machine, skip leaving the house.
But friction is precisely what makes synchrony possible. Syncing with another person requires neurophysiological work – mutual accommodation between individuals, like pendulums on clocks finding their rhythm. And this travels far beneath the surface. Brain imaging studies reveal that the pain of alienation and rejection rivals and can even intensify physical pain perception. That awkwardness on first dates or initial encounters? You're both working hard to establish coordinated rhythm, to get your neural patterns coupling and avoid a painful rejection.
The truth is, we eliminate social friction at our peril. Research consistently shows chance encounters during mundane activities sharpen social skills, reduce anxiety, and spark creativity. Virtual interactions tend to do the opposite. Turning this around requires what philosopher William James called “an extra effort of will” – to banish indifference and embrace syncing with others. You need a balanced diet of social contacts – not just close friends but strangers and loose acquaintances too. So look people in the eye.
Smile. Acknowledgment is a form of kindness, and kindness is catching. Recognize that daily moments of interpersonal synchrony, however brief, are as important to health as eating well, exercising, and sleeping. At the same time, recognize when you're over-syncing and give yourself space to recalibrate. We have a profound instinct to sync. We just need to clear the obstacles blocking our way.
Final summary
The main takeaway of this Blink to Why We Click by Kate Murphy is that interpersonal synchrony shapes every human interaction from birth onward, determining who we instantly click with and who leaves us cold. We're wired to sync because it bonds and coordinates us, yet modern life systematically eliminates the friction-filled encounters that make synchrony possible. Meanwhile, algorithms fragment our shared cultural reference points, leaving millions feeling disconnected despite constant connectivity. The key is finding balance: engaging enough to connect deeply with others while maintaining enough independence to regulate yourself, recognizing that brief moments of genuine synchrony are as vital to wellbeing as sleep or nutrition.
Okay, that’s it for this Blink. We hope you enjoyed it. If you can, please take the time to leave us a rating – we always appreciate your feedback. See you in the next Blink.
About the Author
Kate Murphy is a bestselling journalist and author whose work has appeared in The New York Times, The Economist, and other major publications, with a focus on the science of human behavior and connection. Her previous book, You're Not Listening: What You're Missing and Why It Matters, became an international bestseller exploring the lost art of truly hearing one another.