Longitudinal Evidence for a Midlife Nadir in Human Well‐Being: Results from Four Data Sets
利用四个数据集，仅基于个体内部幸福感变化，发现纵向数据支持幸福感在中年呈U形低谷，反驳了U形是统计假象的观点。
There is a large amount of cross-sectional evidence for a midlife low in the life cycle of human happiness and well-being (a 'U shape'). Yet no genuinely longitudinal inquiry has uncovered evidence for a U-shaped pattern. Thus, some researchers believe the U is a statistical artefact. We re-examine this fundamental cross-disciplinary question. We suggest a new test. Drawing on four data sets, and only within-person changes in well-being, we document powerful support for a U shape in longitudinal data (without the need for formal regression equations). The article's methodological contribution is to use the first-derivative properties of a well-being equation.