Child psychologists at the University of London recently worked with the Grammy-winning singer Imogen Heap to create the perfect song to make babies happy.
The helped create four different melodies, and tested them on 26 kids to find out which one they like most they did it by measuring their heart rates, and looking for cues like how much they smiled.
They also incorporated a bunch of sounds that babies responded to most, like the word "boo", the sound of a dog barking, and the sound of another baby laughing. And they figured out the ideal tempo is 163 beats per minute.
They also wanted lyrics to make sense, so it wouldn't be too annoying for parents.
And they specifically wanted a female singer, since babies tend to like women's voices that sound like their mom.
Here's "The Happy Song" and a making-of video!