Inflammation and intimate others: How the body contributes to close relationships via inflammation

The body is an important contributor to social experience. One specific biological system, the immune system, is known to coordinate social behavior and cognition. Until recently, research on psychoneuroimmunology (i.e., how the immune system impacts and is impacted by our psychological/neurological contexts) has rarely considered how this coordination unfolds in a specific social context: interactions with close others. Although prior research has focused on heightened inflammation predicting social withdrawal, new theory and evidence have begun to suggest social responses to inflammation may differ based on the social target; specifically, humans may approach a close other when experiencing heightened inflammation. Close relationships, and the processes that occur within them, are linked with daily functioning and health. Understanding how the body gives rise to those processes is an important empirical question. By leveraging theory and methods from relationship science, I test the hypothesis that inflammation is positively associated with affiliation-related thoughts, feelings, and behaviors toward a close other in three studies (Chapters 2-4). In the first study (Chapter 2, N = 31), I examine the association between a mild inflammation-induction via the influenza vaccine and automatic social behavior toward differential targets (a close other and strangers). In the second study (Chapter 3, N = 55), inflammation levels and inflammatory reactivity to the influenza vaccine are separately used to predict social-connection-related thoughts, feelings, and behavior toward one close other in daily life. In the final study (Chapter 4, N = 158), I investigate how individual differences in approach orientation toward a romantic partner modulate the association between systemic inflammation (i.e., C-reactive protein or CRP) and sexual well-being. These studies contribute to both psychoneuroimmunology and relationship science by demonstrating how ebbs and flows in peripheral immune activity influence thoughts and behaviors toward our closest others in everyday life.Doctor of Philosoph