Once upon a time, all of our favorite shows used canned laughter—Seinfeld, Friends, Fraiser etc.We all got so used to it that certain tracks were familiar and even predictable. But do you ever wonder what effect it actually had on how we viewed sitcoms? And why don’t we hear it now?Here to share the history, evolution and effects of the laugh track is three-time New YorkTimesbestselling author and pop culture expert, Jennifer Keishin Armstrong.