Amusement is considered an "epistemological" emotion because humor occurs when one experiences a cognitive shift from one knowledge structure about a target to another, such as hearing the punchline of a joke.The pleasant surprise that happens from learning this new information leads to a state of amusement which people often express through smiling, laughter or chuckling.In 1872, Darwin published his book The Expression of the Emotions in Man and Animals, in which he extensively describes his observations of how people and animals display emotions on their faces and through sound.
The theory of constructed emotion suggests that when humans have a positive experience that increases their arousal, such as a faster heartbeat and increased sweat production, they cognitively seek out a label for that feeling.
They will land on amusement if that experience resembles other amusement experiences they have had.
He also notes that across all peoples humans can laugh until they are panting and tears roll down their cheeks.
In the 1960s, Paul Ekman, an American psychologist, revived the study of emotional expression, proposing, like Darwin, that emotions were universally recognizable.
Psychologists from the University of Cambridge and the MRC Unit for Lifelong Health and Ageing have identified a link between positive teen years and a sense of well-being in midlife, and a recent study looking into the effect a happy adolescence has on adult life found that most outcomes are better for happier teens.