The research, conducted with college freshmen who met on the first day of class, found that these snap judgments influenced what kind of relationships actually did develop.
While the power of first impressions has been well known, this research shows that the course of a relationship may be influenced much more quickly than was once believed, said Artemio Ramirez, Jr., co-author of the study and assistant professor of communication at Ohio State University.
"Earlier research had assumed there was a cumulative effect that happens in the first few days of meeting that helps determine how the relationship will develop," Ramirez said.
"But we're finding that it all happens much sooner than that - it's literally within just minutes."
Ramirez conducted the study with Michael Sunnafrank of the University of Minnesota, Duluth. Their findings were published in a recent issue of the Journal of Social and Personal Relationships. For the study, the researchers recruited 164 college freshmen. They were paired on the first day of class with another same-sex student whom they didn't know. They were told to introduce themselves and talk for either three, six or 10 minutes.
After that conversation, they completed a questionnaire that asked them to predict how positive a future relationship with the new acquaintance would be for them personally. They were also asked to predict which type of relationship they thought they would share with the person in the future. They chose from these classifications: nodding acquaintance, casual acquaintance, acquaintance, close acquaintance, friend, and close friend.
They also filled out a variety of other questionnaires examining how much they had in common and how much they liked the person they just met.
Nine weeks later the participants were asked questions to determine the type of relationship that had developed with the classmate they met during that first day's experiment.
Results showed that how positively the participants rated a potential relationship with their new acquaintance on the first day of class was the best predictor of what kind of relationship actually did develop over the next nine weeks.
People who rated the potential relationship more positively tended to sit closer to their partner during class, and communicate more with that person over the course of the nine weeks. After nine weeks, they were also more likely to report a closer friendship had developed.
In fact, how positively people rated a potential relationship was more important than how much the participants said they had in common, and how much they said they liked the person at first meeting, in determining their future relationship.
One important finding was that that results were the same for people who talked three, six and 10 minutes.
"That tells you things are happening very quickly," Ramirez said. "People are making snap judgments about what kind of relationship they want with the person they just met."
People size up the possibilities of a relationship within minutes of meeting, and that guides their actions, he said. This follows what researchers call predicted outcome value theory, which states that when we initially begin communicating with another person we make predictions about the relationship's potential and act accordingly.
"It's almost a self-fulfilling prophecy," Ramirez said. "We make a prediction about what kind of relationship we could have with a person, and that helps determine how much effort we are willing to put into developing a relationship.
"If I think we could become friends, I'll communicate more, tell you more about myself and do things that will help ensure a friendship does develop. If I have a more negative prediction about a future relationship, then I will restrict communication and make it harder for a friendship to develop."
One result is that the person with the most negative view of a possible relationship will have somewhat more influence, he said. "Simply put, if I do not want to talk with you or escalate our relationship, it will be somewhat harder for you to overcome my resistance," according to Ramirez.
Ramirez emphasized that the results don't mean everything about a future relationship is set in stone within minutes of meeting. Obviously, events happen that can change the course of a relationship. And sometimes, people can change their minds about a person they met earlier.
But the study does show the power of the first meeting. "People want to quickly determine if a person they just met is someone they are going to want to hang out with, or date, or spend more time with in the future," he said.
"We don't want to waste our time."
While this study focused on same-sex meetings, Ramirez said it could have applications for dating as well. For one, the study suggests that speed dating - in which you have very short, timed "mini-dates" with a variety of people in one evening - may have real value. While some people have questioned whether you can really evaluate a potential date in just a few minutes, he said this study suggests people already do that.
"Romantic relationships probably are similar to what we found in this study - they begin with people making judgments very quickly," Ramirez said. "We would like to study that in the future."
Right now, Ramirez said he and Sunnafrank are studying what events may change that initial prediction about a relationship, either positively or negatively.