According to Clay Routledge, associate professor of psychology at North Dakota State University, who studies how people bring meaning to their lives through memory, “Nostalgia can be seen as part of the bigger story of how emotions get stored in our memories, neither all positive or negative but as complex, bittersweet feelings.”
They stay with us because of the way that the memories were formed, more intensely than other impressions. What makes it nostalgia, he says, is the strong grasp that a memory has on the psyche and how it keeps affecting us.
“Our memories are the things that make us who we are,” says Joseph LeDoux, professor of neuroscience at New York University and author of numerous popular books that explore emotional memory. “They give us a sense of ourselves and inform our behavior.”