## Nostalgia and Well-Being in Daily Life: An Ecological Validity Perspective Newman, D. B., Sachs, M. E., Stone, A. A., & Schwarz, N. (2020). Nostalgia and well-being in daily life: An ecological validity perspective. *Journal of Personality and Social Psychology, 118*(2), 325-347 Abstract: Nostalgia is a mixed emotion. Recent empirical research, however, has highlighted positive effects of nostalgia, suggesting it is a predominantly positive emotion. When measured as an individual difference, nostalgia-prone individuals report greater meaning in life and approach temperament. When manipulated in an experimental paradigm, nostalgia increases meaning in life, self-esteem, optimism, and positive affect. These positive effects may result from the specific experimental procedures used and little is known about daily experiences that covary with nostalgia. To address this gap, we aimed to measure nostalgia in ecologically valid contexts. We created and validated the Personal Inventory of Nostalgic Experiences (PINE) scale (Studies 1a–1d) to assess both trait and state-based nostalgic experiences. When measured as an individual difference, the nomological net was generally negative (Study 2). When measured in daily life (Studies 3 and 4), nostalgia as a state variable was negatively related to well-being. Lagged analyses showed that state nostalgia had mixed effects on well-being at a later moment that day and negative effects on well-being on the following day. To reconcile the discrepancies between these studies and the positive effects of nostalgia from previous research, we showed that experimentally induced nostalgic recollections were rated more positively and less negatively than daily experiences of nostalgia (Study 5). These studies show that nostalgia is a mixed emotion; although it may be predominantly positive when nostalgic memories are generated on request, it seems predominantly negative when nostalgia is experienced in the course of everyday life.