This research will examine everyday conceptions of nostalgia. Nostalgia serves important psychological functions: it elevates positive affect, boosts self-regard, provides a sense of meaning, fosters self-continuity, and strengthens social connectedness. Yet in relevant studies participants are left to their own devices to conceptualise nostalgia. Also, disagreement exists on whether nostalgia's definitional weight should lie on "missing" aspects of the past or engaging in "sentimental thinking" about aspects of the past. Finally, the proposal findings will be generative, as they will enable investigators to experimentally induce and study nostalgia using an empirically-informed definition. An initial study will attempt to characterise which features or exemplars people perceive as more prototypical (ie central) versus less prototypical (ie peripheral) of nostalgia. This will be accomplished by using an established index of prototypicality, namely the frequency with which participants generate exemplars. The following wave of three studies will implement various techniques in an effort to discriminate in a valid way between central and peripheral nostalgia exemplar categories. Next, the research will seek to confirm in a further wave of three studies that these clusters are more versus less prototypical. These exemplar categories will be used as stimulus materials for the induction of nostalgia.