The Relationship Between Delay and Social Discounting, and Body Mass Index in University Students

Abstract

Delay discounting is associated with body mass index (BMI), with individuals who discount more having higher BMIs. This same relationship was found when a social component was added during a social temporal discounting procedure. However, no study has tested whether the social component by itself is related to BMI. The current study tested the relationships between social discounting, delay discounting, and BMI. Eight hundred seven undergraduates completed delay and social discounting measures, and a demographic questionnaire from which BMI was calculated. Social discounting was not significantly related to age-adjusted or non-age-adjusted BMI. However, using non-age-adjusted BMI scores and dichotomizing individuals as either non-obese/obese resulted in a significant relationship between social discounting and BMI in the predicted direction, whereby participants with a higher BMI shared significantly more than non-obese individuals. Consistent with previous research, there was a significant relationship between delay discounting and BMI, and a significant correlation between delay and social discounting. Additionally, participants with low BMI (< 18.5) appeared to substantially contribute to the significant results. The current results replicated a previous delay discounting and BMI relationship, but also demonstrate the need to standardize how BMI is calculated and focus on participants with low BMI in relation to discounting measures.