AI 中文总结
该研究通过贝叶斯变点框架分析近两百年数据，发现长寿进展的预期年增幅未变但方差有时期变化，近期趋平源于低方差，反驳了长寿进展放缓预示生物学极限的观点。
AI 中文摘要
越来越多文献指出，人类长寿的进展正在放缓，这种放缓可能预示着寿命的生物学极限即将到来。这一论点基于累积预期寿命记录明显趋平的现象，通过线性回归或对比数十年间的平均增幅来评估。然而，这些总结仅能为进展放缓提供薄弱证据，因为它们无法区分真实放缓与表观放缓。表观放缓可能源于年平均增幅不变时的低方差时期。将贝叶斯变点框架应用于最佳实践前沿及各记录保持国的年增幅数据，我们发现近两个世纪以来预期年增幅未发生变化，但方差在不同历史时期呈现明显变化，近数十年的进展最为稳定。近期的趋平现象符合低方差时期的特征，几乎未为潜在平均改进速度下降提供证据。因此，声称最佳实践前沿预示生物学上限的观点不应仅基于累积记录的近期弯曲，该前沿更应被解读为经验基准，即观测历史条件下各国实现的最高特定生存率。
英文摘要
A growing literature argues that progress in human longevity is slowing, and that this slowdown may signal an approaching biological limit to lifespan. The argument rests on visible flattening of cumulative life expectancy records, evaluated through linear regressions or through comparisons of average gains across decades. These summaries, however, provide only weak evidence for slowing improvements, because they cannot distinguish a true from an apparent slowdown. An apparent slowdown may arise due to periods of low variance around unchanged mean annual gains. Applying a Bayesian change-point framework to annual gains, both at the best-practice frontier and separately for each record-holding country, we find no evidence that the expected annual gain has changed across nearly two centuries, but strong evidence that its variance has moved through distinct historical regimes, with progress most regular in recent decades. The recent flattening is consistent with a low-variance regime and provides little evidence for a decline in the underlying mean pace of improvement. Claims that the best-practice frontier signals a biological ceiling should therefore not rest on the recent bend in the cumulative record alone. The frontier is better read as an empirical benchmark, the highest country-specific survival achieved under observed historical conditions.
