We are our memory: a flexible framework for quantifying the demographic imprints of the past

Populations have demographic connections to the past: people who were exposed to the past may still be alive or may at least have living kin. Denton and Spencer and Alburez-Gutierrez have recently articulated the concept of “demographic memory” to refer to the way in which the memory of single events lingers in populations through their age or kinship structure. This article works to clarify, expand, and further demonstrate the usefulness of this concept. Theoretically, it argues for demographic memory as an idea that unifies and makes rigorously quantifiable many of the scattered ideas of historical embodiment that exist across the social and biological sciences, including in sociology, economics, political science, epidemiology, and epigenetics. Methodologically, this article offers a flexible and widely applicable model of “survivorship memory” as the average remembered exposure to past conditions of interest. This model can estimate the memory of events, eras, and continuously varying exposures, and it allows for social stratification in both the exposures of interest and how they are forgotten. As a proof of concept, this new model is applied to the experience of climate change, the recent prime ministers of the United Kingdom, and the strength of liberal democracy across the world.