Chemistry between two people: what it is, and 7 signs you’ll notice early on

What is chemistry between two people?

The most useful definition comes from psychologists Harry Reis, Annie Regan and Sonja Lyubomirsky, whose model of “interpersonal chemistry” appeared in Perspectives on Psychological Science in 2022. In their account, chemistry is the sense that an interaction is more than the sum of what each person brings to it. A few properties stand out:

• It emerges from the interaction. It develops between two people as they talk rather than existing as a fixed trait in either of them. That’s one reason a profile on its own tells you so little about whether two people will click.
• It belongs to one specific relationship. You can be warm and likeable with ten people and feel chemistry with one of them.
• It’s physical as much as verbal. Much of it runs through eye contact, matching expressions and movements that fall into rhythm — often without either person noticing.
• It needs back-and-forth. It can show up in a first conversation, but it builds as small moments of connection pile up.

Chemistry isn’t only romantic, either. Bandmates, teammates and new friends describe it in exactly the same terms.

What determines chemistry between two people?

There’s no checklist, but research keeps pointing to the same handful of ingredients.

Feeling understood. In the Reis model, chemistry grows when one person shares something — an opinion, a worry, a plan — and the other responds with real understanding instead of a stock reply. That kind of responsiveness sits close to the center of how chemistry gets going.

Rhythm. A 2022 study from Dartmouth timed the silences between turns in hundreds of conversations, many of them between strangers. The shorter the gaps, the more connected people felt, both across the whole conversation and moment to moment (Templeton and colleagues, PNAS). How quickly the other person came back to you mattered more than how quickly you answered them.

Laughing together. In an experiment by Laura Kurtz and Sara Algoe, people who shared more laughter with a new partner felt more similar to that partner — and feeling similar made them like the partner more (Journal of Nonverbal Behavior, 2017). The study looked at moments when both people laughed at once, not at how much either of them laughed on their own.

Unconscious mirroring. People tend to copy each other’s posture and gestures without meaning to. In a classic 1999 experiment, Tanya Chartrand and John Bargh had a stranger quietly mirror participants; those participants liked their partner more and rated the conversation as smoother.

What you bring with you. People who are warm and good at seeing things from someone else’s side tend to be easier to click with, and your goals going in — looking for a new friend versus killing ten minutes — color the whole exchange. The Reis model also notes that we project our own hopes onto an interaction, which is one reason two people can walk away from the same chat with different impressions.

7 signs of chemistry in a first conversation

None of these proves anything on its own. Look for several of them together, and for whether they grow as the conversation goes on.

1. 01The pauses shrink. Early on there’s a beat of silence before each answer. When things click, the back-and-forth gets easier and the gaps get shorter. On a video call, connection lag can blur this, so don’t try to time it.
2. 02They build on what you said. Instead of moving on to their next question, they ask about the thing you just mentioned, or bring it back ten minutes later. Follow-up questions are a strong sign someone is actually listening.
3. 03You laugh at the same moment. Not a courtesy laugh after a joke, but the kind where you both crack up at once.
4. 04You start to mirror each other. Similar energy, similar volume, both leaning in at the same time. You’ll usually notice it afterwards, if at all.
5. 05They’re with you, not elsewhere. They react to what you say as you say it and don’t drift off to another tab. On video, don’t read too much into eye direction by itself — people look at the screen rather than the camera, and webcams sit in all sorts of places.
6. 06One topic leads to the next by itself. The first subject runs dry and a new one starts without either of you hunting for it.
7. 07Time slips. You glance at the call timer and it’s been far longer than it felt.

These are clues, not tests. Someone may answer slowly because they’re choosing their words, avoid looking at the camera out of habit, or laugh easily with everyone. The better question is whether you both seem relaxed, engaged and keen to keep going.

Why you’ll probably underestimate it

Even after a conversation that went well, we tend to misjudge how it landed. In a set of five studies, Erica Boothby and three colleagues found that people who had just talked with a stranger believed the other person liked them less, and enjoyed the conversation less, than they actually did. They called it “the liking gap” (Psychological Science, 2018). Outside observers who watched recordings read the partner’s feelings more accurately than the people who had been in the conversation.

The likely reason is attention. We’re busy replaying what we said and how we came across, so we miss the signals the other person is sending. The studies measured liking and enjoyment, not romantic attraction, and the gap showed up as an average across many conversations — but it’s a useful correction. A chat that felt only so-so from your side may well have gone better on theirs.

What no chemistry looks like (and why that’s fine)

Sometimes a conversation never finds its rhythm. The answers stay short, neither of you gets curious about the other, and it starts to feel like one person is doing all the work. That’s different from a comfortable silence, which can happen when things are going well. If the flat pattern holds for a few minutes, the conversation probably isn’t going anywhere — and that says nothing bad about either of you. A conversation can be perfectly pleasant without any spark.

You don’t owe anyone a long goodbye; “Nice talking to you — take care” is plenty. On SpinChat, Next appears a few seconds after a call starts, and hanging up is always an option — there’s one quick “are you sure?” before the call ends.

Chemistry isn’t trust

A strong click can make someone you met five minutes ago feel like an old friend. The feeling is real, but it isn’t information about who they are. Hold back the details that identify you — your surname, where you live or work, your social handles — until trust has had time to build, and be wary of anyone who asks for money or pushes to move the conversation somewhere else quickly. If someone behaves badly on SpinChat, the report and block buttons are on their profile, and reports get reviewed within 24 hours.

If you felt it, keep the thread

Meeting by chance has one downside: there’s no obvious way to find each other again. On SpinChat you can follow someone during a call or from the screen that appears when it ends, and later open their profile from your call history to send a message. If they’re on the online list, you can call them from there — the call connects only if they answer.

A second conversation may not feel like the first; chemistry tends to shift as two people learn more about each other. There’s one way to find out.