“One has to spend so many years in learning how to be happy,” 25-year-old George Eliot wrote in an 1844 letter to a friend. But rather than directed at a static end goal, this learning is a dynamic recalibration of our very definition of happiness as we move through different life-stages. “Human beings,” Harvard psychologist Daniel Gilbert observed a century and a half after Eliot as he contemplated our illusory understanding of happiness, “are works in progress that mistakenly think they’re finished.”

The evolving conception of happiness over the human lifetime is what Stanford social psychologist Jennifer Aaker and her team study in order to help us better calibrate what we believe makes us happy to what actually makes us happy. In this animated short film for the Future of Storytelling Summit — which also gave us Margaret Atwood on how technology shapes storytelling — Aaker outlines how the primary definition of happiness shifts in five systematic stages over time: discovery during childhood and adolescence, pursuit in our mid-twenties, balance in our late twenties and early thirties, meaning in our late thirties and forties, and savoring from our fifties on. But these chapters, Aaker illustrates through her team’s studies, need not be linear or sequential — different life-experiences help us reorder and edit them.

Our meaning of happiness is constantly shaped and reshaped by small choices we make every day.

Complement with Rebecca Goldstein on the continuity of personhood over time, Albert Camus on happiness, unhappiness, and our self-imposed prisons, and these seven essential books about the art-science of happiness.