But in recent years the time frame sociologists have been using to define a generation has been shrunk down to ten years, then five, and now three. It is even possible that there is a "generation gap" between brothers and sisters in the same family, something that previously only happened between parents and children.
以前講代間差異，人的一生是一代；在近年的社會學研究裡，代間已從十年、五年，一路縮短到三年，現在的兄弟姊妹間，甚至可能已有過去親子間的「代溝」。