Sexual and romantic partnerships play a central role in social life, and they serve as the key social engines that drive human reproductive success. Close relationships come in all shapes and sizes and—as compellingly described in Eastwick, Finkel, and Simpson’s (this issue) valuable target article—lengths. Some relationships last an hour or a day; others last for months or years; and still others last a lifetime. Understanding the key psychological differences between “short-term” and “long-term” relationships is a critical goal for research. A relationship’s longevity can reflect the goals that people bring to the partnership, as well as the functions that partnership may be intended to serve. Moreover, providing insight into the links between relationship longevity and relationship function paves the way for a conceptual framework that unites traditional relationship science perspectives with evolutionary perspectives. Questions associated with relationship length and relationship function are central to both perspectives, so addressing those questions sets the stage for an integrative framework that helps bridge the two subfields of psychological science.

中文翻译：

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性关系和双亲关系类似于毛毛虫和蝴蝶吗？人类交配的双系统视角

性和浪漫伙伴关系在社会生活中发挥着核心作用，它们是推动人类生殖成功的关键社会引擎。亲密关系有各种形状和大小，而且——正如 Eastwick、Finkel 和 Simpson（本期）有价值的目标文章中令人信服地描述的那样——长度。有些关系持续一小时或一天；其他持续数月或数年；还有一些会持续一生。了解“短期”和“长期”关系之间的关键心理差异是研究的一个关键目标。关系的持久性可以反映人们为伙伴关系带来的目标，以及伙伴关系可能旨在服务的功能。而且，深入了解关系寿命和关系功能之间的联系，为将传统关系科学观点与进化观点结合起来的概念框架铺平了道路。与关系长度和关系功能相关的问题是这两个观点的核心，因此解决这些问题为构建有助于弥合心理科学两个子领域的综合框架奠定了基础。