I used to love singing to my now-toddler son when he was a baby. I would rock him back and forth in my arms and croon to him as he drifted off into dreamland. I would even make up my own lullabies. Singing was—and still is—my favorite way to communicate with him.

Of course, I am not the only mother who loves belting out a tune for their baby. And now research shows us the benefits of those mama-led lullabies.

A new study presented at the 25th annual meeting of the Cognitive Neuroscience Society on Tuesday found that lullabies not only comfort both mama and baby, but they can also benefit an infant’s cognitive development. Particularly, these songs can increase a little one’s attention and displays of positive emotion toward their mamas.

“Infant brains must be able to track auditory events in a predictive manner to make sense of music,” says study author Laura Cirelli, a postdoctoral fellow at the University of Toronto. “Music is a tool that we can use to bring people together, and this starts in infancy.”

For the study, the research team, led by Cirelli, analyzed the ways in which mamas sing to their babies depending on their end-goal: To soothe or to play. The moms who participated in the study would sing “Twinkle Twinkle Little Star” repeatedly to their little one, alternating between a joyful tone and a calming one.

The researchers measured both mom and baby’s arousal responses through behavior and skin conductance—a phenomenon where the skin becomes a temporary conduit of electricity as a response to external or internal stimuli.

What they found is arousal levels decreased for mom and baby when mama sang soothing lullabies. But arousal levels only increased for mamas when they used a more playful tone while crooning to their infants. The babies, on the other hand, paid more attention to their mothers and displayed more positive emotions, but had stable arousal levels, according to the findings.

“We are seeing relationships between rhythm and language abilities, attention, development, hearing acuity, and even social interactions,” says study co-author Jessica Grahn, a cognitive neuroscientist and associate professor at the University of Western Ontario. “Every sensation we have or action we make on the world unfolds over time, and we are now beginning to understand why humans are sensitive to certain types of patterns in time, but not others.”

These findings, though, are not surprising. Previous research has found that singing can have a tremendous impact on how babies interact with their parents and the world.

Cirelli’s new research builds off of her past work studying how music and rhythm impacts behavior and social interactions. One study, published in 2015 in the Annals of the New York Academy of Sciences, found that people became more socially connected when moving in sync to music.

The results were replicated in another study, published in Infancy in 2016. In that study, 14-month-old infants who were bounced in sync with unfamiliar adults were more helpful towards those adults than babies who bounced out of sync.

What’s more: Two Harvard Medical School researchers found that singing lullabies to infants evolved as a way to calm wailing or fussy babies. Infant-directed songs also allow parents to signal their attention to their little ones, reassuring their babies that they will be kept safe, according to their research.

Speaking to The Harvard Gazette, Max Krasnow, an assistant professor of psychology at Harvard University, says, “Infant-directed song has a lot of these costs built in. I can’t be singing to you and be talking to someone else. It’s unlikely I’m running away, because I need to control my voice to sing. You can tell the orientation of my head even without looking at me; you can tell how far away I am even without looking.”

Singing is a powerful tool of motherhood, and now mamas have the research to prove that it has long-lasting benefits on their development. So keep carrying that tune, mama, even if you’re off-key, because your baby’s listening and they love every moment of it.