The goal of this paper is to discuss which basic semantic entities we should include in our formal semantic ontology, and on which principles we should include them (cf. Bach 1986b). The vast majority of formal theories employ individuals as a basic type; they represent quantification over, modification of, and reference to individuals. But many theories include additional types or entities, including possible worlds, but also less common ones like vectors. Some papers have argued that types should be constrained or reduced; others that they should be proliferated. I present some representative arguments on both sides and suggest a path forward in evaluating them against one another.

A science of close relationships stands to benefit from an understanding of the situations in which interactions between partners take place. In this chapter, we briefly review recent advances in situation research. Within the current decade, several new taxonomies have been put forward that describe how people perceive situations. Functional Interdependence Theory, in particular, posits that people are well-prepared to understand situations in terms of interdependence. New instruments based on Functional Interdependence Theory and other taxonomies for the first time allow researchers to measure in a comprehensive way how people subjectively perceive situations. Coupled with experience sampling methods, which allow the collection of psychological measures in everyday life, these instruments enable researchers to paint a full picture of the interdependent situations people experience in their relationships. We discuss how studying the situations partners experience together in daily life allows researchers to find new answers to questions arising from a) Interdependence Theory, b) Attachment Theory, and c) theorizing on relationship maintenance behaviors. Finally, we offer a framework for research on situational interdependence in close relationships.

Romantic relationships affect the levels of security that people generally experience with close others. Experiences with a partner carry immediate outcomes (e.g., feeling appreciated vs. ignored), but they also can have longer lasting effects when they cause people to reflect on their overall worthiness and comfort with closeness/trust toward others. Our chapter examines how such experiences shape the mental representations that underlie chronic tendencies with attachment security, and how these representations may change with new experiences in romantic involvements. We examine change through the lens of the Attachment Security Enhancement Model, which suggests that enhancing security in relationships involves both mitigating momentary insecurity and fostering more secure mental representations over the longer term. Whether partners are effective at enhancing security may depend on the strategies they enact, and optimal strategies depend on whether a person is experiencing momentary anxiety versus avoidance. Over time, partner strategies in new situations – especially those that depart from past insecure experiences (e.g., painful interactions in close relationships) – can lead to revisions of insecure mental representations (e.g., beliefs about the self, expectations of close others). Together, using strategies to manage insecure moments and create opportunities to revise insecure mental representations may enhance security across time.

How do people maintain their closest relationships? In this chapter, we present an interdependence account of how people maintain their relationships with others. Interdependence theory, first articulated by Thibaut and Kelley, was formulated to explain how people choose among potential courses of action in interdependent situations featuring problems of actor coordination and decision-making. Because romantic partners are often faced with daily choices within their relationship (e.g., Should we go to the movie my partner wants to see rather than what I want to see? Should I stay in this relationship or pursue an alternate?), interdependence theory is well suited for understanding relationship maintenance processes. We begin by discussing why relationship maintenance is necessary. We then review the set of processes – behavioral and cognitive – that help keep interdependent relationships intact, despite the fact that situational actors must adapt to constantly changing situations. Central to these processes is one’s commitment to a relationship, which, once established, causes maintaining a relationship to become an automatic, default option under ordinary circumstances.