My friends and I have shared a lot over the years: dorm rooms and apartments, stories of high school crushes and every little detail of the date one of us went on, and cover letters via Google Docs. Over time, we’ve even adopted one another’s mannerisms and language quirks… without necessarily being able to pinpoint how or why. (Case in point: I regularly say, “Y’all,” even though I grew up in Pennsylvania.) According to psychology, we’ve all been unintentionally blending our quirks and camouflaging with one another á la the chameleon effect.

A peculiar phenomenon of social psychology, the chameleon effect “describes the unconscious tendency most people have of mimicking, or mirroring, another person’s facial expressions, non-verbal behaviors, and verbal expression,” says licensed counselor Suzanne Degges-White, PhD, LCPC, NPC. (To be clear, we’re talking about the kind of mimicking that happens unintentionally; by contrast, plenty of people use intentional mimicry as a form of manipulation, which is not the same thing as the chameleon effect.)

Much like the term’s eponymous creatures can change their colors, we tend to unconsciously shape-shift our mannerisms to match those with whom we’re interacting in a social environment—and as we become more like them, they become more like us.

Within close friendships and relationships, that effect can ramp up over time: “The more time you spend with people, the more you begin to create similar habits—whether they’re social habits, behavioral habits, or communication habits,” says behavioral-health expert Julie Radlauer-Doerfler, DrPH, LMHC.

But you don’t actually need to have any prior relationship with someone to experience the chameleon effect in real time. (That could explain why I recently started speaking in a British accent to a stranger who had a British accent.) Indeed, the researchers who first identified the chameleon effect, psychologists Tanya Chartrand, PhD, and John Bargh, PhD, found that this kind of unintentional mimicry could occur even among strangers interacting with “non-smiling strangers” with whom they never made eye contact and had no existing “goal to affiliate.”

Why does the chameleon effect happen?

The chameleon effect says that, whether it’s your best friend’s midwestern accent or a stranger’s smile, you may automatically reciprocate, and the research points to evolutionary reasons as to why. According to a 2003 review of research on behavioral mimicry, we may unintentionally copy the behaviors of people around us to up our chances of being accepted into a group—which would’ve been a necessary skill for our ancestors, who often had to rely on others for help with survival activities like finding food and defending against predators.

It’s for that reason that researchers have called the chameleon effect a form of “social glue:” Copying someone can unconsciously strengthen your bond with them. “The chameleon effect generally has a positive influence on the interrelationship between two people as it leads them to believe that they share similarities with each other and are in sync,” says Dr. Degges-White. She adds that mirroring of our behaviors can make us trust others more, view them as more attractive, and feel more connected to them.

“The chameleon effect…leads [two people] to believe that they share similarities with each other and are in sync.” —Suzanne Degges-White, PhD, licensed counselor

The research supports these assertions, too. In Dr. Chartrand and Dr. Bargh’s original studies on the chameleon effect, they found that mimicry facilitated greater liking and rapport. In particular, those participants whose movements were mirrored by a conversation partner reported liking that person more and thought the interaction went more smoothly than those in a control condition that didn’t involve any copying. Imagine just how much mirroring may be happening on a great first date or in a comfortable conversation between friends.

To that end, unintentional mimicry is one way that our minds are unconsciously working to make sure that we get along with others. After all, the better our interactions go over, the more we can satisfy our fundamental need for belonging and develop the kinds of social connections and relationships that help us live a longer, healthier life.

What are a few examples of the chameleon effect in action?

You can spot the chameleon effect in play among friends who share one another’s greetings (just take the example of my own free-flowing use of “y’all”) or behavioral quirks, like the way they cross their legs.

“When hanging out with friends, we often reflect their posture, their facial expressions, and their energy when they are sharing about the good or the disappointing things in their lives,” says Dr. Degges-White. To me, this is a pretty special thing: You’re becoming more like the people whom you most care about… and they’re becoming more like you.

With strangers, you might not notice the chameleon effect as readily, but it’s there if you look for it. Perhaps you start sitting like the person across the waiting room from you at the doctor’s office, or in response to someone giving you a compliment on your shirt, you give them one right back on their shirt.

According to Dr. Degges-White, there’s one behavior, in particular, that gets passed along especially easily—and that’s smiling. “It’s the quintessential example of unintentional mimicry,” she says. “Human beings are pretty much hardwired to smile when another person smiles at them.” (If you’re reading this right now, just know that I’m smiling at you from afar.)

Who is most prone to engaging in the chameleon effect?

Like most social phenomena, the chameleon effect is not experienced equally by everyone, even though it’s thought that we all engage in it to some degree. People who have certain personality traits that open them up to the experiences of others, and those who find themselves in positions where making quick social connections is key may have more chameleon tendencies than others. Here are a few categories of people who fall into that bucket:

Empathetic people

In Dr. Chartrand and Dr. Bargh’s initial research, those with certain empathetic tendencies mirrored the behaviors of their conversation partners more readily.

In particular, they found that people high in perspective-taking (the act of adopting the psychological viewpoint of others) were more likely to copy the mannerisms of people with whom they interacted. Which makes sense: Being able to put yourself in another person’s shoes would likely mean you’re more perceptive of their behaviors and, in turn, more open to adopting them.

People in new situations

“In situations where we are unsure of ourselves or in new environments, like a job interview or the first day on a new job, we may be more likely to engage in chameleon behaviors to ensure that we look like we fit in and don’t stand out in a negative way,” says Dr. Degges-White.

In these scenarios, our unconscious tendency to copy others can work in our favor by helping us to form quick connections and make a good first impression.

People whose jobs rely on social connections

People who have roles where forming quick bonds with strangers is necessary, including salespeople and counselors, are often trained to capitalize on the chameleon effect and may get used to mirroring gestures and language to build rapport, says Dr. Degges-White. “When a counselor mirrors their client’s body language or reflects back what the client says, it can make the client feel that their counselor [better] understands them,” she says.

For similar reasons, a salesperson who mirrors the mannerisms of a client may endear them to make another purchase. And by the same token, research has found that servers in a restaurant who mimicked their customers’ behaviors at both the initial and final stages of their interactions earned higher tips than those who didn’t.

How to embrace the social benefits of the chameleon effect

1. Let yourself be a copycat

Engaging in the chameleon effect (which is, again, a subconscious act) can be a sign that you are tuning into your environment and focusing on the people around you. It will ultimately benefit your relationships with your favorite people.

“By attuning to others in your company, you are showing them that you care about them and understand them, which deepens the relationship,” says Dr. Degges-White. Our brains developed this imitation tendency for a reason; use it for the social glue that it is.

2. Be aware

The most important thing about the chameleon effect is to be aware of it (kudos to you for reading this article). Because it is an involuntary process, all you can really do is notice that it’s happening and understand why it’s happening and how it might affect you and your relationships.

Even though the chameleon effect helps to build trust in relationships, it could also cause you to adopt habits from people in your sphere that you don’t necessarily want. Consider how a friend’s annoying tendency to check their phone every 30 seconds might rub off on you, for example.

“Just as you can recognize that hanging around people with bad habits can cause you to develop bad habits yourself, you can also recognize that the opposite is true: Spending time around people with good habits will help you to develop good habits,” says Radlauer-Doerfler.

That doesn’t mean you have to go get rid of your phubbing friend—but it’s important to be aware that behaviors are contagious, and setting intentions for better habits may support you and those around you. Let the good catch on.

3. Trust your instincts

Remember: Intentional mimicry is an entirely different thing from the chameleon effect and is often used as a manipulation tactic. “Always trust your gut instincts about someone whom you catch mimicking you, especially when their behavior or mimicry seems to be a ploy to get you to like or accept them when you otherwise wouldn’t,” says Dr. Degges-White.

If a person’s attempt at mimicking you actually makes them stand out to you (rather than making them feel like a more comfortable presence), that’s a sign to second-guess their intentions.