Empirical evidence about the development of social relationships across adulthood into late life continues to accumulate, but theoretical development has lagged behind. The Differential Investment of Resources (DIRe) model integrates these empirical advances. The model defines the investment of time and energy into social ties varying in terms of emotional closeness and kinship as the core mechanism explaining the formation and maintenance of social networks. Individual characteristics, acting as capacities, motivations, and skills, determine the amount, direction, and efficacy of the investment. The context (e.g., the living situation) affects the social opportunity structure, the amount of time and energy available, and individual characteristics. Finally, the model describes two feedback loops: (a) social capital affecting the individual’s living situation and (b) different types of ties impacting individual characteristics via social exchanges, social influences, and social evaluations. The proposed model will provide a theoretical basis for future research and hypothesis testing.

关于从成年到晚年社会关系发展的经验证据不断积累，但理论发展滞后。资源差异投资 (DIRe) 模型整合了这些经验性进展。该模型将时间和精力投入到不同情感亲密度的社会关系中，作为解释社会网络形成和维持的核心机制。个人特征，作为能力、动机和技能，决定了投资的数量、方向和效果。背景（例如，生活环境）会影响社会机会结构、可用时间和精力的数量以及个人特征。最后，该模型描述了两个反馈循环：(a) 影响个人生活状况的社会资本和 (b) 通过社会交流、社会影响和社会评价影响个人特征的不同类型的联系。所提出的模型将为未来的研究和假设检验提供理论基础。