Norman Ryder, writing in American Sociological Review in 1965, shed light on the sociology of the discord between generations by suggesting that society "persists despite the mortality of its individual members, through processes of demographic metabolism and particularly the annual infusion of birth cohorts".
Norman Ryder (1965) estudou a socioloxía das discordancias entre xeracións ao suxerir que a sociedade "persiste a pesar da mortalidade dos seus membros individuais, por procesos de metabolismo demográfico e particularmente a infusión anual de cohortes de nacementos".