Couple conflict has received significant attention in couples research, chiefly because poorly managed conflict raises risk for a host of negative outcomes including relationship dissatisfaction, divorce, domestic violence, occupational impairment, and poor child well-being. Effective conflict management is a central target of couple therapy and relationship education. In this chapter, we define couple conflict, describe the frequency and common topics of conflict, and provide examples of how researchers measure conflict. We then describe different ways that couples manage conflict, highlighting effective and ineffective conflict management behaviors and how they affect relationship functioning. Next, we describe conflict and conflict management among historically underrepresented couples. Last, we present information on relationship interventions that target couple conflict and describe future directions for research on couple conflict.

Research has advanced our understanding of the role of self-disclosure in the initiation, development, maintenance, and ending of relationships. In this chapter, we review theoretical and empirical milestones in our understanding of self-disclosure, particularly its role in relationships. We show that research on self-disclosure has shifted from a focus on the individual to a focus on the interpersonal nature of disclosure processes. Self-disclosure occurs between people and triggers a cyclical process that is specific to a particular relationship with a particular partner. Self-disclosure processes fluctuate over time. They shape, and are shaped by, relationships. We propose that self-disclosure serves as a seismograph of relationship quality. It is essential in interdependent relationships and key to unraveling how people perceive the quality of their relationships. Throughout the chapter, we identify unanswered questions that offer promising avenues for future research.

This chapter is devoted to developing and clarifying one of the most unique and important constructs of attachment theory: the internal working models (IWMs) by which relationships influence other relationships and personality. We begin by describing how IWMs develop, discuss different definitions and conceptualizations of IWMs associated with different developmental stages, and then offer a new way of thinking about IWMs as both implicit and explicit representations that function at different levels of awareness. We then discuss factors that promote stability and change in IWMs, highlighting how earlier experiences with attachment figures may shape subsequent IWMs associated with other attachment figures. We next present a framework outlining the conditions under which IWMs associated with specific attachment figures earlier in life can become “activated” to influence how people think, feel, and/or behave with their current attachment figures. We conclude by proposing several promising directions for future research.

Social networks have always influenced the day-to-day interactions of people, and our chapter highlights the latest research on the significance of these noteworthy social ties in people’s personal relationships. We attend to both romantic relationships and friendship connections, focusing on themes of network effects in relationship formation, maintenance, and dissolution. The findings we review underline the notable ways in which the social environment shapes our closest connections and often strengthens them. We also discuss the extension of network science to investigate marginalized relationships, such as those of sexual minorities, and note the potential for social networks to have a “dark side” in which social connections become problematic. We then address emerging scholarship regarding the positive and negative links between COVID-19 and social networks. Finally, we consider future avenues for research on this notable topic.

Research concerning the variety of close relationships adults maintain, initiate, cease, and lose during middle and later adulthood has been fast growing in recent decades. Much of the theoretical and empirical work in this field has aimed to overcome views of older age as a time of loss and decline, both individually and socially. Moreover, recent trends have focused on the increasingly diverse experiences of the aging population. This includes not only extended life expectancy – and, importantly, extended healthy life expectancy – but also demographic changes, including larger proportions of racial/ethnic minorities attaining older age; new cohorts of openly LGBTQ adults entering mid and later life, many of whom represent the first generation of same-sex married couples; and the phenomenon of “gray divorce” and romantic repartnering in the years beyond age 50. This chapter will cover both the history and foundations of research on close relationships in middle and later life, as well as these recent trends in the field, finishing with an eye toward future directions as both the aging population and our perceptions of it continue to change.

People form different types of relationships with others. One common, valued, type is a communal relationship. In communal relationships, people assume responsibility for one another’s welfare and give and seek responsiveness non-contingently. Here we review ways in which communal relational contexts shape people’s emotional lives. In communal relationships, giving and receiving non-contingent responsiveness is linked to positive emotion, whereas failure to do so or behavior indicative of following inappropriate norms (e.g., norms governing transactional relationships) leads to negative emotion. In addition, the presence of communal partners often reduces threat and enhances the intensity of positive and negative reactions to environmental stimuli. Communal contexts are associated with greater expression of emotions signaling one’s own needs (which partners sometimes socially reference as signs of their own needs) and with expressing more indicative of empathy and care for the partner. All these effects can feed back and strengthen communal relationships.

We examine family systems and family relationships. Using family systems theory (Cox & Paley, 1997, 2003; Minuchin, 1985), we focus on how families are viewed as a hierarchically organized system, comprised of smaller relationships (i.e., subsystems) such as parent–child relationships, embedded within larger systems such as extended families and their broader social ties. We organized the discussion of subsystems as follows: (a) Core subsystems, including relationships of romantic partners, coparenting alliance, parent–children, and siblings; and (b) Subsystems with broader social ties, in the form of extended family and/or intergenerational ties, including coparenting alliances in post-divorce or foster families as well as parents and parents-in-law relationships. We also consider these various subsystems within and across diverse families and family contexts, attending to aspects of gender, family structures, income, sexual orientation, race/ethnicity, cultures, and national origins. We end with suggestions for future research (e.g., combining the lenses of family systems with intersectionality).

Relationship maintenance scholars have long attempted to understand the processes by which partners foster relationship growth. They have done so by focusing on defining and explaining key maintenance strategies that serve to initiate and preserve romantic relationships. In this chapter, we provide a brief history of the relationship maintenance literature. Then we identify the key theoretical contributions to the current understanding of relationship maintenance and discuss recent theoretical developments and known correlates. We conclude the chapter by highlighting the need to diversify and expand the maintenance literature by identifying possible avenues for future inquiry and proposing ways to integrate work across disciplines.

Social relationships are a fundamental component of the human experience, and decades of relationships research supports their central role in health and well-being. This chapter offers a broad look at research on social support in the context of close relationships, with particular emphasis on the role of social support in health. We first give an overview of the foundational theories of the field and discuss how social support has historically been conceptualized. We then discuss contemporary extensions of this work, including theories of invisible support, perceived responsiveness, thriving, dyadic perspectives of coping, and the implications of technology for support processes. We highlight important research on social support in diverse gender and cultural contexts, emphasizing the need for intersectional perspectives in this space. The chapter concludes with a discussion of key considerations for future research and intervention.

The current chapter focuses on the development of adolescents’ relationships with parents, friends, and romantic partners, and their role in youth’s psychosocial adjustment. The chapter describes how relationships with parents in adolescence go through a period of transition toward a more egalitarian and reciprocal relationship, with temporary decreases in connectedness and increases in conflict in the process. Adolescents’ relationships with friends become more supportive and acquire a more optimal balance between intimacy and respect for each other’s individual needs over the course of adolescence. Positive experiences of adolescents in relationships with parents and friends predict healthy romantic functioning and satisfaction later in adolescence and emerging adulthood. Romantic involvement and relationship quality typically progresses towards increased attachment and intimacy functions in late adolescence and young adulthood. Satisfactory romantic relationships and a healthy sexual development tend to go hand-in-hand. High-quality relationships with parents, friends, and romantic partners are typically associated with positive socioemotional outcomes.

In this chapter, we review and integrate the literature on friendships and acquaintanceships in adulthood. We begin with a broad perspective on friends and acquaintances by considering them as members of a larger social network, with friends as part of the inner layers and acquaintances in the outer layers. Then we review the literature focused on friendships, including their life course (formation, maintenance, and endings). Most friendships begin as acquaintances, but not all acquaintances become friends. In a third section we focus on the diverse types of acquaintances, factors associated with how many acquaintances people have, and the unique needs met by acquaintances. Friends and acquaintances have influences on many areas of people’s lives including their romantic relationships and their health and well-being, which are issues also discussed in this chapter.

Research on sex in relationships has proliferated in recent years, yielding valuable insights about sexuality in different types of relationships. In this chapter, we highlight recent work that has strengthened our understanding of couples’ everyday sexual experiences and their links to relational and broader well-being. We review how sexual experiences are shaped by individual differences (e.g., attachment orientation) and by the interplay of both romantic partners. We further highlight how the field has adapted to societal changes in relationships (e.g., consensual non-monogamy, casual sex, technology). Although existing research has discovered many important findings, much of it is limited in its generalizability to diverse populations beyond Western, monogamous, and cisgender man–woman couples. To address this oversight, we offer many minor but meaningful adjustments researchers can make to help ensure their measures and theories are inclusive, thereby helping to ensure future research on sex in relationships is representative of a broader population.

Social relationships are not only linked to emotional well-being, but also significantly associated with physical health. Reviewing the epidemiological and experimental body of research reveals evidence of directional and potentially causal associations between social connection and health and longevity. This is consistent with theoretical approaches to social relationships including attachment, social baseline, social network, and social support theory, all of which identify social relationships as vital to health and well-being. Theoretical models further conceptualize how it is that social relationships influence health. The growing scientific evidence documents some of the biological and behavioral pathways involved. While the evidence on the associations between social relationships and health is robust, the literature is uneven pointing to the need for further research on the complex nature of relationship quality and tech-based social connection.

Relationship science spans multiple disciplines of inquiry, ranging from neuroscience to demography, and is a dynamic enterprise, rich with ongoing discovery. The field’s breadth and pace thus present both challenges and opportunities to those who introduce it to others. This chapter draws on surveys and interviews of instructors to consider their choices of the topics they teach, comparing the content of relationships courses from one discipline to another. Substantial similarities and disciplinary distinctiveness are both found to exist. Then, we focus on the partnerships between teachers and their students, examining how specific relationship processes (such as self-disclosure) and qualities of instructors (such as empathy and immediacy) contribute to student engagement and learning. We also address new challenges in the teaching of relationship science that include the remote nature of online instruction, the increasing diversity of our students, and the emergence of generative artificial intelligence. Finally, the value of relationships courses to the students who take them is assessed.

This chapter provides an overview of major empirically supported approaches to treating relationship distress among committed couples based upon criteria proposed by Chambless and Hollon (1998). Based on these criteria, we discuss behavioral couple therapy and its derivatives, including cognitive behavioral couple therapy and integrative behavioral couple therapy; emotionally focused couple therapy, and insight-oriented couple therapy. Each approach’s underlying theory and empirical support are described. We also note the development of a trans-theoretical model emphasizing central factors across theoretical approaches. This chapter also examines theoretical and empirical work on couple interventions beyond treatment of general distress to applications with specific, difficult-to-treat relationship problems, such as intimate partner violence (IPV). We also review couple-based interventions for individual problems, with an overview of some empirically-supported conjoint treatments for psychopathology. In addition, we address the importance of ensuring that interventions are sensitive and appropriate for couples traditionally underrepresented in empirical studies of couples (e.g., older couples, same-sex couples). Finally, we briefly discuss teletherapy and internet-based interventions to assist couples.

As far back as Aristotle, humans have been recognized as social animals. Most scholars, regardless of their theoretical background, agree that social connections are the basis of the human condition. From birth, and even before, our relationships with others are key to survival (Reis et al., 2000). Infants who have close social bonds with their primary caretakers are more likely to thrive during their lives than those who do not (Groh et al., 2017). As children grow, their primary dyadic relationships proliferate into webs of social connections (Weeks & Asher, Chapter 8, this volume). These social connections, in turn, give rise to the creativity, structure, and ingenuity that allow us to improve society. Clearly, the advances that humans have made depend heavily on collective action.

Daily hassles and critical life events cause stress not only to individuals but also to close others, particularly partners in committed relationships. This chapter covers an overview of theoretical models and empirical studies on the effects of stress on couples and dyadic coping (DC; how couples cope with stress together). In the 1990s several theoretical innovations expanded individual coping to include both members of the couple. These theoretical models are briefly reviewed and synthesized in a general model of DC, the Systemic Transactional Model (STM), which is the most frequently used in research. We provide a current overview of empirical studies about couples dealing with daily hassles, major life events, and chronic stress, like physical health issues and disability or mental disorders. DC has been established internationally as a highly relevant construct in many disciplines. Recent developments are addressed and implications given for future research and clinical applications.