Why do we feel Nostalgia?

Every week, we see photos and stories of our friends, family, and the brands we follow on “Throwback Thursday”. It's a fun way to look back and learn some history and/or reminisce of a fun memory. But why do we feel nostalgia? Well, Clay Routledge, in a TEDEd lesson, details the way our understanding of nostalgia has changed since the term was first coined in the late 17th century.

Source: https://ed.ted.com/lessons/why-do-we-feel-nostalgia-clay-routledge