More than a century ago Leo Tolstoy noted that happy families tend to be more similar to each other than unhappy families. Was this just a cognitive illusion, driven by his mind’s predisposition to see positive entities as more similar to each other, or did he make a profound observation about the world? If it is true, is the phenomenon limited to happiness, or is it a characteristic of positive traits more generally? This question has received attention in multiple fields, but not in psychology. We ran five studies, testing the more general hypothesis that people who share some positive individual-difference trait are more alike than those who do not (The Convergence of Positivity Hypothesis), and we consistently found empirical support for it. Happier, healthier, and richer people were more alike in their personality, values, and in various other domains. The research approach we followed here departs from traditional behavioral science methods and proposes a different level of analysis, where valence and directionality play a central role. We speculate about why this pattern might exist and about the boundary conditions, including whether it extends beyond individual differences to a broader set of complex systems where positivity can be defined.

一个多世纪以前，列夫·托尔斯泰 (Leo Tolstoy) 指出，幸福的家庭往往比不幸的家庭更相似。这只是一种认知错觉，是由于他的思维倾向于将积极的实体视为彼此更相似，还是他对世界进行了深刻的观察？如果这是真的，这种现象是否仅限于幸福，或者它是更普遍的积极特质的特征？这个问题在多个领域都受到了关注，但在心理学领域却没有。我们进行了五项研究，检验了一个更普遍的假设，即具有某些积极个体差异特征的人比那些不具有某些积极个体差异特征的人更相似（积极性趋同假设），并且我们始终为它找到实证支持。更快乐、更健康、更富有的人在性格、价值观、以及其他各个领域。我们在这里遵循的研究方法不同于传统的行为科学方法，并提出了不同层次的分析，其中效价和方向性起着核心作用。我们推测为什么这种模式可能存在以及边界条件，包括它是否超越个体差异扩展到可以定义积极性的更广泛的复杂系统集。