Nostalgia

Nostalgia is an emotion which is often described as a bittersweet longing for the past, typically for a period of time accompanied by happy memories or emotions. It is often described as a sort of sad pleasure, which typically involves longing for a past memory, whether real or romanticized, that cannot be recovered. It can also refer to a type of homesickness.

The word nostalgia is a neoclassical compound derived from Greek, consisting of νόστος (nóstos), a Homeric word meaning "homecoming", and ἄλγος (álgos), meaning "pain"; the word was coined by a 17th-century medical student to describe the anxieties displayed by Swiss mercenaries fighting away from home. Described as a medical condition—a form of melancholy—in the early modern period, it became an important trope in Romanticism.

Nostalgia is associated with a longing for the past, its personalities, possibilities, and events, usually described as the "good old days" or the "glory days". There is a predisposition, caused by cognitive biases such as rosy retrospection, for people to view the past more positively and the future more negatively. When applied to one's beliefs about a society or institution, this is called declinism, which has been described as "a trick of the mind" and as "an emotional strategy, something comforting to snuggle up to when the present day seems intolerably bleak".

The scientific literature on nostalgia usually refers to nostalgia regarding one's personal life and has mainly studied the effects of nostalgia as induced during these studies. Emotion is a strong provoker of nostalgia due to the processing of these stimuli first passing through the amygdala, the emotional seat of the brain.