Date of Award
2026
Degree Type
Restricted to Claremont Colleges Dissertation
Degree Name
Psychology, PhD
Program
School of Social Science, Politics, and Evaluation
Advisor/Supervisor/Committee Chair
Saida Heshmati
Dissertation or Thesis Committee Member
Tiffany Berry
Dissertation or Thesis Committee Member
Jeanne Nakamura
Terms of Use & License Information
Rights Information
© 2026 Olivia Ellis
Subject Categories
Psychology
Abstract
The present studies aimed to address the issue of declining physical activity levels across adulthood by expanding upon the upward spiral theory of lifestyle change (Black et al., 1996; Westerterp, 2018a, 2018b). The theory posits that when individuals experience positive emotions during health behaviors such as physical activity, it can contribute to the broaden-and-build effect by building vantage resources that further support the health behavior (Anderson & Heyne, 2016; Fredrickson & Joiner, 2018; Fredrickson et al., 2020). However, research is lacking when looking at the shared experience of positive emotion (i.e., a micro-moment of love, labeled positivity resonance) and when thinking about how enduring resources can also be built from positive emotion experienced outside of the health behavior. Prior research has demonstrated that social resources can have a strong influence on physical activity levels and that social and emotional influences become even more prominent motivators as individuals age (Notthoff & Carstensen, 2014; Steltenpohl et al., 2019). Thus, I conducted two studies to address the declines in physical activity levels across the lifespan through shared positive emotions. In Study 1, 159 adults ages 18 and older were recruited using Prolific with equal representation of each of the adulthood stages: young (n = 55), middle (n = 54), and late adulthood (n = 50). Participants were asked to complete the trait positivity resonance questionnaire (a measure of a tendency to experience micro-moments of love, broadly defined), answer questions regarding their perception of social resources, and report physical activity levels across seven days. Data analysis assessed whether (in line with the upward spiral theory of lifestyle change and broaden-and-build theories) trait positivity resonance predicts physical activity levels and whether stage of development across adulthood moderates the relationship. Furthermore, I explored whether social resources help explain the relationship between positivity resonance and physical activity levels. The results suggested there was a relationship between trait positivity resonance and physical activity levels, however, the relationship was not moderated by stage of development and the relationship was not mediated by social resources. While Study 1 assessed the variables at a global level, Study 2 expanded upon Study 1 by looking at positivity resonance, social resources, and physical activity levels as they occur in people’s day-to-day lives, across seven days using the Day Reconstruction Method. This helps to better understand the relationship between positivity resonance and physical activity levels and whether social resources mediate the relationship when measured across days. Study 1 suggested the relationship between positivity resonance and physical activity levels was not stronger for a specific developmental stage (e.g., young, middle, or late adulthood), thus, I explored all adult stages of development in Study 2 in similar manner to Study 1. Study 2 consisted of 152 adult participants (ages 18 and older). Multilevel modeling was utilized in the data analysis. The results suggested that average daily positivity resonance did not predict same-day or next-day physical activity. Furthermore, although average daily positivity resonance was related to average daily social resources, social resources did not act as a positive mediator for physical activity. However, in a post hoc analysis average daily positivity resonance did predict same-day moderate physical activity. The results help inform our understanding of social and emotional factors related to physical activity engagement and potential extensions of the upward spiral theory of lifestyle change. Furthermore, the paper addresses developmental implications of these findings.
ISBN
9798244860085
Recommended Citation
Ellis, Olivia. (2026). The Proposed Role of Positivity Resonance in Building Social Resources to Address Physical Activity Declines Across Adulthood. CGU Theses & Dissertations, 1096. https://scholarship.claremont.edu/cgu_etd/1096.
