What is the Purpose of Nostalgia?

Nostalgia is kind of like a craving for bad fast food. Everybody occasionally gets it, but we don’t really think about where it comes from or why it’s there. Well, most people don’t think about it. Clay Routledge of North Dakota State has spent years researching nostalgia, and in a new paper he and his colleagues provide a comprehensive explanation of the strange sensation.

Through a series of six experiments Routledge and his colleagues demonstrate that nostalgia “serves an existential function by bolstering a sense of meaning in life.” In other words, nostalgia is one of the many psychological defenses we employ to fight negative thoughts, emotions, and mental states. Nostalgia is specifically used to make life feel more meaningful when we feel life lacks meaning.

In the first two studies the researchers showed that nostalgia increases our sense of meaning in life. The next two studies demonstrated that nostalgia increases when the meaning of our lives is threatened, and that this nostalgia increase decreases defensiveness that results from the threat. The final two studies showed that nostalgia can help mitigate the connection between “meaning deficits” and lower psychological well-being.

The question I have is whether there are diminishing returns if nostalgia is “used” too often. For example, if a feeling that life lacks meaning leads you to experience nostalgia for the first time in a week, will a nostalgic experience the following day have a smaller effect? Do you need periods without nostalgic experiences for the power of nostalgia to “charge up?”