If you feel like a lot of pop songs these days are starting to sound the same, there’s a theory that’s taking off on the Internet: they all feature something called “the millennial whoop.”

What is “the millennial whoop”?

Coined by The Patterning writer Patrick Metzger, the millennial whoop is “a sequence of notes that alternates between the fifth and third notes of a major scale.” Basically, it’s that part in California Gurls where Katy Perry starts vocalizing “wa-ohh-wa-ohh” during the bridge (check out 1:05 to see what we mean).