Nostalgia strengthens global self-continuity through holistic thinking.

Nostalgia, a sentimental longing for one's meaningful past, promotes global self-continuity (GSC), a sense of connection among one's past, present, and future selves. We identified a cognitive mechanism for this effect: holistic thinking, and in particular interactional causality (presupposing multiple causes that interact to influence an object's behaviour). In three studies, using measurement-of-mediation and experimental-causal-chain designs, nostalgia was related to, and caused, higher GSC through interactional causality. In cross-sectional Study 1, trait nostalgia was associated with GSC via interactional causality. In Study 2, induced nostalgia led to higher interactional causality and ensuing GSC. In Study 3, manipulated interactional causal thinking increased GSC.