When your normally happy baby isn’t her usual smiley self and you’ve run through all of your usual tricks and tried-and-true games, what’s next?

Music is an ideal mood booster and boredom buster—for both of you. Babies love a joyful noise, rhythm, and silly sounds, and with the right tunes you’ll be rewarded with a gummy grin and a giggle more often than not.

Why? Unlike some of the other senses, hearing develops very early, so little ones are fascinated by sounds. And they especially love sharing songs and dances with their parents. Music, singing, and movement all stimulate your baby’s senses, which in turn promote brain development.

What Makes a Perfect Baby Song

You can sing almost any song with and to your baby, but there’s a little secret to what babies really like. Experts have dissected what makes a song captivating to babies, and here’s what they found. An ideal baby song:

• Is in a major key—which gives a song a more positive sound than a minor key does.
• Has a repetitive melody—so babies can anticipate what’s coming.
• Also has surprises, like key changes and drum rolls, because happy surprises delight babies.
• Is up-tempo to align with a baby’s heart rate, which is quicker than an adult’s.
• Is sung by a woman; babies tend to prefer female voices (even more so if the woman is singing in the presence of a real live baby!).
• Is silly—packed with sounds guaranteed to generate baby hilarity, like raspberries, animal sounds, and (yep!) other babies laughing.
• Is packed with “plosive” sounds: Think “b” and “p” words, like beep, which babies respond to more readily than “sonorant” sounds, like the la las you might hear in a lullaby.
• Is cute and fun for parents, too, because sharing makes enjoyment greater.

Keep these in mind while you’re making up songs with your baby (you’re probably doing it anyway, instinctively!) and see what she responds to. Maybe funny sounds are her favorite, or an infectious rhythm. Don’t be afraid to make up words, drum with your fingers, or just generally act goofy. Your baby will love it!

The Baby Playlist

If you need help figuring out what to sing, try “The Happy Song,” which is the result of the research mentioned above, or any of these winning tunes:

Classic kiddie songs: “The Wheels on the Bus,” “Old MacDonald Had a Farm,” “Down by the Bay,” and “Galumph Went the Little Green Frog”

Broadway: “You Can’t Stop the Beat” (Hairspray), “76 Trombones” (The Music Man), “Do-Re-Mi” (The Sound of Music), “Footloose” (Footloose), and “The Room Where It Happens” (Hamilton)

Pop music:“Happy,” Pharrell Williams; “Shake It Out,” Florence and the Machine; and “Can’t Stop the Feeling,” Justin Timberlake