The history of emotions has yielded substantial studies on love, anger, fear, grief, jealousy, and many other discrete emotions. However, there is no particular study of cheerfulness, a rather moderate emotion, which, for reasons that I will discuss further, has remained unnoticeable to the scholarly eye. Based on much of the historical literature on emotions, some primary sources and some other areas of cultural history, I outline here the social use and conceptualization of cheerfulness over the last three centuries. I argue that, in the modern age, cheerfulness rose in value and became the most favored emotion for experience and display; as such, it was individually sought and socially encouraged until it became the main emotional norm of twentieth-century America.

Lived emotional experience is key to language learning, the authors suggest. "Mathematicians and physicists may manipulate abstruse symbols representing space, time, and quantity, but they first understood those entities as tiny children wanting a far-away toy, or waiting for juice, or counting cookies. The grown-up genius, like the adventurous child, forms ideas through playful explorations in the imagination, only later translated into the rigor of mathematics."