There are a few specific chord progressions that show up again and again in popular music. Across hundreds of hit songs, the same basic musical formulas have been used by artists ranging from Lynyrd Skynyrd to Lady Gaga, and from Bob Marley to Blink-182. So where did these musical tropes even come from, and what makes them so enduring? Featuring music journalist Jennifer Gersten and comedic musician Benny Davis.  Follow the show on Twitter, Facebook, & Reddit. Subscribe to our Youtube channel here. Become a monthly contributor at 20k.org/donate. If you know what this week's mystery sound is, tell us at mystery.20k.org. Get a 4-week trial, free postage, and a digital scale at Stamps.com. Just click the microphone at the top right corner and type the promo code 20k. Compare home and car insurance rates at policygenius.com. Episode transcript, music, and credits can be found here: https://www.20k.org/episodes/progressionobsession Learn more about your ad choices. Visit megaphone.fm/adchoices