New research finds that when we first enter into a romantic relationship we do not know if it will be short-term and casual, or long-term and serious.

The finding contradicts the belief that long-term and short-term relationships are different from the beginning. Many have believed that one type of relationship is good for someone you would want to marry, while others are more about sex.

Researchers discovered that when a relationship is viewed over the long run – that is, from the moment you meet someone until the moment the relationship is over for good – it takes a while for the differences in short-term and long-term relationships to emerge.

“Long-term and short-term trajectories typically pull apart after you’ve known someone for weeks or months,” said Dr. Paul Eastwick, an associate professor of psychology at University of California Davis.

Eastwick is the lead author on the study published in the Journal of Experimental Psychology: General.

“In the beginning, there is no strong evidence that people can tell whether a given relationship will be long-term and serious or short-term and casual.”

Eastwick and his co-authors surveyed more than 800 people from a wide range of ages. They used a state-of-the-art “relationship reconstruction” survey in which people reproduce the events and experiences they had in their prior real-life short-term and long-term relationships.

Importantly, Eastwick and his colleagues asked the participants to reconstruct these relationships from the very beginning. This procedure differs from the standard “relationship science” approach, which starts studying people once they are already in a dating relationship.

“Some of the most interesting moments in these relationships happen after you meet the person face-to-face, but before anything sexual has happened,” Eastwick added.

“You wonder ‘Is this going somewhere?’ or ‘How much am I into this person?’ It is somewhere around this point that short-term and long-term relationships start to diverge, and historically, we have very little data on this particular period of time.”

The researchers found that romantic interest rises at the same rate in both short-term and long-term relationships. But at some point, romantic interest tends to plateau and decline in short-term relationships, while in long-term relationships, it continues to ascend and reaches a higher peak.

What is the moment when the two trajectories start to diverge? On average, it happens at about the time that the relationship starts to become sexual.

“People would hook up with some partners for the first time and think ‘wow, this is pretty good.’ People tried to turn those experiences into long-term relationships,” said Eastwick.

“Others sparked more of a ‘meh’ reaction. Those were the short-term ones.”

The study offers a perspective on the distinction between the stable, long-term partner and the exciting, short-term partner.

Researchers discovered that in real life, people may end up in short-term relationships when they are “just a little” attracted to the other person; enough to keep having sex, but maybe not for very long. Conversely, long-term relationships may be the ones that start especially exciting and sexy and grow into something stable and lasting.

Source: UC-Davis