Background: This study examines how loneliness and the body’s stress response system interact to regulate social connections. We suggest that the drive to reconnect signaled by loneliness can be accompanied physiologically by the production of cortisol, which can offer supportive coping resources. Thus, we investigated how loneliness, cortisol levels, and their interaction predicted changes in network connections in a social organization. Participants (n = 193; 53% female) provided friendship network data at two times. At time 1, participants reported on loneliness and donated saliva (later assayed for cortisol). Results revealed that concurrently, lonely individuals reported fewer friendships, whereas over time, they named more friends. These results support the hypothesis that loneliness is a signal to develop connections. We also explored whom lonely individuals befriended over time. Results showed that cortisol significantly moderated the preference for friends with a similar level of loneliness. Specifically, lonely individuals with higher cortisol befriended those who were less lonely over those who were lonelier. Thus, cortisol levels may serve an adaptive function in mobilizing resources to develop connections that fulfill social belongingness needs. Results supported the theorized signaling function of loneliness and revealed that loneliness and the stress response system interact to shape social connections.
This study investigates the social determinants of health by examining how mucosal immunity is associated with the patterning of social connections in a network. Studies have suggested that social networks have biological underpinnings, but investigations at the scale of networks, rather than individuals, have remained elusive. We integrate salivary bioscience methods with advanced social network modeling to explore the association between salivary secretory immunoglobulin A (SIgA), a key component of mucosal immunity, and social network structure.
Friendship network data and saliva samples (later assayed for SIgA) were obtained from a large mixed-gender social organization (n = 155, 55% female, M age = 19.5 years).
Exponential random graph modeling revealed that SIgA levels were positively associated with reporting more friendship ties with community members (i.e., social network activity), after controlling for other processes associated with network structure including preference to befriend others of the same age, gender, and extraversion, increased network popularity of agreeable individuals and those with lower levels of perceived stress, as well as network structural and organizational processes.
By examining a wider range of associations between SIgA and network structure, we pinpoint that SIgA is positively associated with respondent’s sociability. Our findings are consistent with social integration theories linking social relationships to health and highlight the role of humoral immunity as a possible mediator of these associations.