Nostalgia is a sentimentality for the past, typically for a period or place with happy personal associations. The word nostalgia is learned formation of a Greek compound, consisting of νόστος (nóstos), meaning "homecoming", a Homeric word, and ἄλγος (álgos), meaning "pain" or "ache", and 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 yearning for the past, its personalities, possibilities, and events, especially the "good old days" or a "warm childhood".The scientific literature on nostalgia usually refers to nostalgia regarding the personal life and has mainly studied the effects of nostalgia induced during the studies. Smell and touch are strong evokers of nostalgia due to the processing of these stimuli first passing through the amygdala, the emotional seat of the brain. These recollections of one's past are usually important events, people one cares about, and places where one has spent time. Music and weather can also be strong triggers of nostalgia.
Functions
Nostalgia's definition has changed greatly over time. Consistent with its Greek word roots meaning "homecoming" and "pain," nostalgia was for centuries considered a potentially debilitating and sometimes fatal medical condition expressing extreme homesickness. The modern view is that nostalgia is an independent, and even positive, emotion that many people experience often. Occasional nostalgia has been found to have many functions, such as to improve mood, increase social connectedness, enhance positive self-regard, and provide existential meaning.
