Date of Award


Degree Type

Open Access Dissertation

Degree Name

Psychology, PhD


School of Social Science, Politics, and Evaluation

Advisor/Supervisor/Committee Chair

Kendall Cotton Bronk

Dissertation or Thesis Committee Member

Tiffany Berry

Dissertation or Thesis Committee Member

Jeanne Nakamura

Dissertation or Thesis Committee Member

Sarah Schnikter

Terms of Use & License Information

Terms of Use for work posted in Scholarship@Claremont.

Rights Information

© 2020 Susan Mangan


Emerging Adulthood, Need Satisfaction, Positive Activity Intervention, Positive Psychology Intervention, Well-Being

Subject Categories



Emerging adults (18-30 years old) may be vulnerable to reduced well-being and psychological need satisfaction, which refer to a meta-theory of self-determination theory which reflects the degree to which individuals feel skilled (competence), connected to others (relatedness) and in control of their own decisions (autonomy) (Deci & Ryan, 2011). Increasing psychological need satisfaction represents one promising strategy for increasing well-being (Mackenzie, Karaoylas, & Starzyk, 2018). To date no positive psychology interventions have been created specifically to foster need satisfaction; however, four interventions have examined need satisfaction as an outcome. In this study, these four positive psychology interventions were tested to determine which ones most increased well-being, overall need satisfaction, and each individual dimension of need satisfaction. Additionally, this study sought to extend previous research to emerging adult populations by testing whether the impact of interventions on well-being is mediated by need satisfaction, and whether balanced need satisfaction (i.e., feeling similar levels of autonomy, competence, and relatedness vs. feeling highly satisfied with some needs but less satisfied with others) contributes to well-being for emerging adults. In a pretest-posttest experimental design, 335 emerging adults were randomized to one of four experimental conditions (random acts of kindness, character strengths, self-affirmations, or best possible selves) or a control condition for a period of two weeks. Results indicated that participants completing acts of kindness and self-affirmation activities showed the largest increases in need satisfaction and well-being. The results of this study failed to replicate previous studies, indicating that positive psychology interventions may not have the potential to increase well-being indirectly by increasing need satisfaction directly. Additionally, this study failed to replicate the importance of balanced need satisfaction score on well-being. Thus, the results of this study do not support that balanced need satisfaction scores significantly add to well-being in emerging adults. This study represents the first step in designing positive psychology interventions for cultivating need satisfaction among emerging adult populations. Limitations and future directions are discussed.



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