2023年第58講總第809講
題目：The Impact of Longevity on Fertility Decisions（長壽對生育決策的影響）
地點🫴🏼：意昂3体育516
時間：2023年12月22日13:30-16:30
主講人：Pro. Zhen Zhang, Ph.D in Demography, Director of Institute of Population Studies, Fudan University. His research expertise and interest include survival and longevity, population aging, formal demography, social demography. Zhen's recent research includes how the abnormally high sex ratio at birth accelerates population aging in China and other affected countries. His earlier publications include Population Health Transition in China: Achievements in the Co-evolution of Health Governance and Health Strategies, Population Aging Caused by a Rise in the Sex Ratio at Birth, The Ratio of Expansion to Compression: A New Measure of Lifespan Disparity, Impact of Demographic Uncertainty on Population Projection and Policy-making: The Case of China. Zhen received Ph.D in Demography at Peking University. Before moving to Fudan University in 2013, Zhen held a position as Research Scientist at the Max Planck Institute for Demographic Research in Rostock, Germany.
張震，人口學博士♣️，教授🏌🏼♂️🦶🏿，復旦大學人口研究所所長。他的研究專長和興趣包括生存和壽命💧、人口老齡化🤸🏻、形式人口學🤷🏻♂️、社會人口學9️⃣。張震最近的研究聚焦於異常高的出生性別比如何加速中國和其他受影響國家的人口老齡化。他早期的發表作品包括《中國的人口健康轉型：衛生治理和衛生戰略共同演變的成就》、《出生性別比上升引起的人口老齡化》、《擴張與壓縮的比率🧝：一種壽命差距的新測量》、《人口預測和政策製定中人口不確定性的影響😦：以中國為例》🧘🏽♂️。張震畢業於北京大學，獲人口學博士學位👩👩👧👧。2013年加入復旦大學之前💂🏿♂️，張震曾在德國羅斯托克的馬克斯•普朗克人口研究所擔任研究員。
內容簡介：Increased longevity not only gives us more time, it also lengthens the period of return on our investments. Our early investments in education, health care and skills development have the advantage of a longer payback period. As lifespan disparity decrease, the expectation of sustained returns over time becomes more predictable and stable. Strategies with fewer children have a higher resilience and a stronger survival advantage than having more children. Due to the principle of compound interest, investment returns are likely to grow exponentially, which means that gaps due to underinvestment in human capital in earlier years are also likely to grow exponentially. As life expectancy increases, these cumulative lifetime financial setbacks can become considerable. From an evolutionary game theory perspective, the proportion of people adopting the first strategy increases over time across the population, and the fertility rate of the population declines. Thus, increased longevity greatly increases the cumulative cost of the investment in reproductive time, which in turn depresses fertility.
壽命的延長不僅給予我們更多時間，而且延長了我們投資回報的周期，使我們在教育、醫療和技能發展方面的早期投資具有更長期的回報優勢📂。隨著壽命差距的減小，對持續回報的期望隨著時間的推移變得更加可預測和穩定。相較於生育更多的子女，采取較少子女的策略具有更高的彈性和更強的生存優勢。復利的原則的影響下，投資回報很可能呈指數增長，這意味著由於早期對人力資本的不足投資而產生的差距也可能呈指數增長。隨著預期壽命的不斷延長，這些累積的終身財務挫折可能變得相當可觀。從進化博弈理論的角度來看🎅，采取第一種策略的人口比例隨時間在整個人口中增加，人口的生育率下降👨👨👧👦。因此，增加的壽命大大增加了生殖時間投資的累積成本，進而抑製了生育率。
