It's hard to pinpoint the exact factors that transform a superficial acquaintanceship into a full-fledged friendship.
But years of research suggests there's one near-universal feature of relationship development: self-disclosure.
In general, according to research by Nancy L. Collins, Ph.D., and Lynn Carol Miller, Ph.D., people tend to like each other more after they've shared something personal.
The foundation of friendships is sharing details about your lives, from the mundane (my favorite food is cheese, too!) to the more consequential (my dad just lost his job).
There are two key elements to self-disclosure, and both are pretty easy to botch.
One, the sharing has to be mutual. It's unlikely a strong friendship will develop between two people if one person spends all day griping and the other one simply listens, without revealing anything about himself.
That idea is based on research by Susan Sprecher, Ph.D., at Illinois State University. Sprecher and colleagues recruited 156 undergrads and paired them up in Skype conversations, during which they answered a series of questions about themselves.
The questions got increasingly personal. The first set included questions like "What are your favorite hobbies?" The next included questions like "Would you like to be famous?" The final set included questions like "What is your happiest childhood memory?"
Half the student pairs took turns answering the questions — so one person would talk for 12 minutes and then the other person would start. The other group engaged in back-and-forth conversation during two 12-minute Skype conversations.
At the end of the experiment, the students indicated how much they liked the other person, how close they felt to them, and how much they enjoyed the conversations.
Results showed that the students who engaged in back-and-forth conversations liked each other a lot more than the students who took turns speaking. They also felt closer to each other and claimed to enjoy their interactions more.
The study authors write that their findings have important implications for people who feel uncomfortable in social situations: "Although shy or socially anxious people may ask questions of the other to detract attention from themselves, our research shows that this is not a good strategy for relationship initiation. Both participants in an interaction need to disclose to generate mutual closeness and liking."
In other words, assuming the other person isn't being inappropriate and you want to continue the relationship, encourage yourself to step out of your comfort zone. If someone shares somewhat personal information, try to respond in kind.
Another key element of self-disclosure is that you can't get too personal too fast.
If you reveal something highly intimate, especially something negative, early on in a relationship, it suggests that you're insecure and can decrease your likability, according to research by Valerian J. Derlega, Ph.D., and colleagues.
Remember that, in Sprecher's study, participants weren't discussing their romantic lives or how much they hated their coworkers. The deepest they got was talking about happy childhood memories. Yet even these relatively superficial conversations brought them closer.
If you allow self-disclosure to happen gradually, you'll have a better chance of forging and maintaining a friendship — one that eventually will allow you to talk about things like your dating life and annoying colleagues.
Bottom line? It's generally a good idea to reciprocate when someone you're hoping to befriend shares something personal. But don't get overeager and confide everything in that person right away.
SEE ALSO: Psychologists may have discovered the best way to make new friends as an adult
Join the conversation about this story »
NOW WATCH: TONY ROBBINS: These are the 2 most important keys to success