The reason why couples have nicknames and speak in baby talk is way more fascinating than we expected

You may lovingly (or not so lovingly!) roll your eyes when you hear your couple friends call each other by nicknames or pet names, but we’ve all done it with our significant others behind closed doors — and enjoyed it. So what gives? Why do couples use nicknames and pet names, and speak to each other in baby talk? Aren’t we past this stage after, like, age 4?

The good news is that science says this seemingly absurd behavior is actually the mark of a great relationship, and that couples do this the world over. So, in short, we’re here to tell you you’re completely normal if you haven’t called your partner by their actual name in months, or even years. Phew!

But why does this behavior feel so good, and is it a mark of modern times? We’re here to answer all of your questions.

Why do couples call each other by nicknames?

The short answer to this question is, nicknames create a sense of intimacy between partners, a shared world that only you two understand and live in.

Said Carol Bruess, author of the preeminent 1993 study, “‘Sweet Pea’ and ‘Pussy Cat’: An Examination of Idiom Use and Marital Satisfaction Over the Life Cycle,” in an interview with Scientific American, “I think it’s a really human, natural behavior to take language and shape it for our own purposes. I think that’s how nicknames evolve. We name things, we give things symbols, and over time we tend to naturally manipulate those symbols toward a certain outcome.”

Indeed, according to her research, this kind of idiosyncratic communication — or “couplespeak” — is actually a marker of marital satisfaction. The more couples are communicating in their own language, the better things likely are at home. It’s a sign of “relationship solidarity,” so to speak.

Why do so many cutesy pet names start with the letter “b”?

Now that we know why couples call each other pet names, why do so many begin with the letter “b”? Baby, babe, boo, bae, bubba, bunny, bug, bb — a huge number of our go-to nicknames as a culture start with this gentle letter. And it goes all the way back to babyhood: According to Dr. Frank Nuessel, a University of Louisville professor and expert in onomastics — AKA the study of naming — the letters b, m, and p are among the easiest to make (because they require no tongue movement) and so are among the first sounds babies make.

When parents coo at their little ones, they mimic their babies’ infantile speech, saying words like “mama,” “papa,” and “baba.” That, in turn, translates to a sense of intimacy and closeness, a feeling that lingers later in life.

“When parents, and usually it’s the mother who interacts the most, tries to teach the baby language, they use the terms of the child: mama, papa, baba,” said Nuessel. “Then the adults transfer the language to other adults or significant others in their life, and they use those as terms of endearment.”

This goes for baby talk between couples, too — those endearing, babble-laden conversations between adults and children feel just as sweet between grown-up romantic partners. In fact, according to an article in Psychology Today, baby talk and pet names between partners replicate the feeling of being loved by your parents as children — that unconditional, secure love we all crave. Not to mention, that kind of intimate talk produces a chemical reaction in the body that indicates security and closeness. Dopamine, oxytocin, and phenylethylamine — all bonding chemicals — are boosted by baby talk and nicknames.

Is this a modern phenomenon?

It’s not! Pet names have been used for centuries, with “baby” dating back to the 17th century and versions of “sweetheart” uncovered in the 13th-century writings of an Anglo-Saxon saint. So if you’re calling your lover a cutesy name, congratulations. You’re part of a long, healthy tradition of expressing undying affection.