Connection, Disconnection and the Social Mind: Interpersonal Relationships in a Lonely Century

Abstract

Interpersonal relationships have moved from the periphery of social psychology to the centre of public health. This article examines what the discipline has established about how relationships form, sustain wellbeing and fail, and how that knowledge should be revised in light of three developments: the recognition of social disconnection as a global health risk, the diversification of relationship forms, and the arrival of artificial intelligence as a relational partner. It reports a comparative secondary analysis synthesising the 2025 report of the World Health Organization Commission on Social Connection, recent OECD and national survey evidence, and recent meta-analytic and experimental studies of relationship processes. Four findings emerge. First, disconnection is common and consequential: about one in six people worldwide experience loneliness, rising to roughly one in four in low-income countries, and loneliness is associated with an estimated 871,000 deaths annually. Second, the processes that sustain relationships are well identified - responsiveness, self-disclosure, commitment and the repair of rejection - and their effects are moderate rather than dramatic. Third, relationship structures are more variable than commonly assumed: a meta-analysis of 24,489 participants finds no satisfaction difference between monogamous and consensually non-monogamous relationships, while goal congruence shows one of the larger associations with satisfaction reported in the literature (r = .43). Fourth, artificial-intelligence companions can reduce loneliness in the short term and are already used for relational needs by substantial minorities, raising design and governance questions the discipline has only begun to address. The article argues that relationships should be analysed at three levels - motivational, interpersonal and structural - and that the field's central applied task is now the design of environments that make connection easy.