I study how people initiate, develop, and maintain close relationships, including friendships and romantic relationships. Three overarching sets of questions guide my research: (1) How do people’s offers and requests for support change as partners develop close relationships? How does their understanding of the relational meaning of offering and requesting support change across the lifespan (e.g., from childhood to adulthood)? (2) How do people react to partners’ signs of initial interest or disinterest in a relationship? What are the implications of these reactions for their relationships? (3) How do unique features of the relationship context shape partners’ physiological, behavioral, and psychological responses to stressful situations in newly-formed relationships? I use diverse methodologies to investigate these questions, including developmental approaches, biological methods, field studies, experimental designs, and longitudinal and daily-report studies. I also teach courses in the psychology of close relationships, social psychology, and introduction to psychology.