Recent research proves relationship compatibility may be linked to how things are said more than the content of the conversation.

A study titled “Language Style Matching Predicts Relationship Initiation and Stability,” published on Dec. 13 in the journal Psychological Science, found the degree to which people subtly match one another’s speaking and writing style affects the success of those relationships.

Psychology professors conducted two experiments. The first involved speed dating and the second analyzed instant messages between committed couples. The tests focused on Language Style Matching, or LSM, a measurement of verbal synchronicity based on the use of “function words.”

“These are the kinds of words you would not notice other people using, much less notice yourself using,” said Dr. Richard B. Slatcher, professor of psychology at Detroit’s Wayne State University and one of the study’s co-authors. “These are things like pronouns, articles and prepositions.”

Function words are short connecting words, such as “the,” “as” and “on,” which have little meaning by themselves. The research proposes similarities in the use of these commonly spoken and written words reflect the coordination of psychological states and relationship compatibility.

“Until now, studies that have looked at the interpersonal consequences of behavior matching have focused on nonverbal behaviors,” Slatcher said. “Earlier research pretty much ignored the fact that people in relationships actually talk to one another. Our study is the first to show the extent to which people match [each other linguistically] matters big time.”

The first study analyzed four-minute speed dates between 40 women and 40 men. As hypothesized, the study found LSM to significantly predict relationship initiation among speed daters. Dr. Eli Finkel, associate professor of Social Psychology at Northwestern University and co-author of the study, said the findings were surprising

to him.

According to Finkel, people tend be unaware of why they are drawn to others, but scientists are developing ways to figure this out.  Analyzing the subtleties of language is one of those methods.

The first study found speed daters were more than three times as likely to match with their date for every standard-deviation increase in LSM. Basically, for every percentage two people matched in the use of function words, the probability they would go on a second date nearly tripled.

“We were amazed at how an incredibly subtle measure of how people match each other in the words they use [LSM] was predictive of critical relationship outcomes,” Slatcher said.

In the second study, LSM in writing was tested. Instant message conversations between 86 couples were evaluated for LSM. For 10 consecutive days, the couples provided their IM chats for the study. Three months later, follow-ups were conducted on the relationships.

“It’s hard to clearly and consciously perceive these differences,” said Dr. Paul W. Eastwick, assistant professor of psychology at Texas A&M University. “It’s not clear that people have strong control [regarding] this aspect of their language. It’s extremely subtle.”

The study showed LSM to be a strong indicator of whether two strangers ended up choosing each other for a date after speed dating, according to Slatcher.

“It also predicted whether couples in existing relationships broke up or stayed together down the road,” Slatcher said. “This was big news.”

The results suggest everyday verbal synchronicity strongly indicates whether strangers will romantically connect and whether couples will stay together.

The more frequently couples did not match each other’s language pattern the less likely they were to stay together.

More studies are being conducted to understand how language and relationship contentedness are related.

“Our lab is currently using digital tape recorders, called the Electronically Activated Recorder, or EAR, to investigate Language Style Matching in couples’ daily lives,” Slatcher said. “My guess is the findings from this study will end up confirming what we have found in our earlier research—that LSM is a key indicator of relationship success.”