2019 Wilkins-Bernal-Medawar lectureLife begins at 40: the demographic and cultural roots of the midlife crisis.

In 1965, the psychoanalyst and social scientist Elliott Jaques introduced a term, the 'midlife crisis', that continues to structure Western understandings and experiences of middle age. Following Jaques's work, the midlife crisis became a popular means of describing how-and why-men and women around the age of 40 became disillusioned with work, disenchanted with relationships and detached from family responsibilities. Post-war sociological and psychological studies of middle age regarded the midlife crisis as a manifestation of either biological or psychological change, as a moment in the life course when-perhaps for the first time-people felt themselves to be declining towards death. Although the midlife crisis has often been dismissed as a myth or satirized in novels and films, the concept has persisted not only in stereotypical depictions of rebellion and infidelity at midlife, but also in research that has sought to explain the particular social, physical and emotional challenges of middle age. In the spirit of the pioneering research of John Wilkins, John Bernal and Peter Medawar, each of whom in different ways emphasized the complex interrelations between science and society, I want to argue that the emergence of the midlife crisis-as concept and experience-during the middle decades of the twentieth century was not coincidental. Rather it was the product of historically specific demographic changes and political aspirations-at least in the Western world-to keep alive the American dream of economic progress and material prosperity.