Examining the Associations Between Body Mass Index, Rejection Sensitivity, and Stress-Reactivity Following Social Exclusion

Open Access
Geller, Andrew
Area of Honors:
Biobehavioral Health
Bachelor of Science
Document Type:
Thesis Supervisors:
  • Joshua Morrison Smyth, Thesis Supervisor
  • Helen Marie Kamens, Honors Advisor
  • Body Mass Index
  • Rejection Sensitivity
  • Stress-Reactivity
  • Social Exclusion
The prevalence of obesity in America has escalated dramatically over the last half- century, and research suggests that it will become even more ubiquitous in the coming decade. Although the biological consequences of obesity are well understood, there is a dearth in our comprehension of how social and psychological factors may contribute to poor health outcomes for overweight and obese individuals. For this thesis, secondary data analyses were conducted from The Social Interactions and Health Project (n=120), where data from a two-group randomized control experiment titled “Cyberball” was used to examine whether differences in Body Mass Index (BMI) and rejection sensitivity (the anxious expectation and anticipation for rejection) moderated stress-reactivity (change in heart rate and cortisol level) following social exclusion. Six regression models were computed to analyze the effects of BMI and rejection sensitivity on change in heart rate and cortisol level for participants who were randomly assigned to the Cyberball exclusion condition. BMI was a statistically significant predictor for change in cortisol following social exclusion (β = -0.005, p=0.036). However, rejection sensitivity and the interaction between BMI and rejection sensitivity were not statistically significant predictors of change in heart rate or cortisol level following social exclusion. Specifically, there was a decrease in cortisol levels following social exclusion, suggesting that BMI predicts blunted stress-reactivity following social exclusion. Overall, the results suggest that overweight and obese individuals may be at risk of blunted physiological reactions following social exclusion. When coupling these blunted physiological reactions with the biological complications of obesity, a synergistic effect may exist where a combination of biological and physical factors results in worsened health outcomes for overweight and obese individuals.