Financial motivation undermines potential enjoyment in an intensive diet and activity intervention

Abstract

The use of material incentives in healthy lifestyle interventions is becoming widespread. However, self-determination theory (SDT) posits that when material incentives are perceived as controlling, they undermine intrinsic motivation. We analyzed data from the Make Better Choices trial-a trial testing strategies for improving four risk behaviors: low fruit-vegetable intake, high saturated fat intake, low physical activity, and high sedentary activity. At baseline, participants reported the degree to which financial incentives were an important motivator (financial motivation); self-reported enjoyment of each behavior was assessed before and after the 3-week incentivization phase. Consistent with SDT, after controlling for general motivation and group assignment, lower financial motivation predicted more adaptive changes in enjoyment. Whereas participants low in financial motivation experienced adaptive changes, adaptive changes were suppressed among those high in financial motivation.

Fig. 1

Financial motivation predicting changes in liking (FV, Fat, PA, and Sed). a Fruits and vegetables*. b Saturated fat*. c Physical activity* d Sedentary leisure. Note: Asterisk indicates a significant financial motivation × time interaction. The “High” and “Low” financial motivation slopes represent predicted slopes associated with plus and minus one standard deviation from the sample mean, respectively, on the continuous financial motivation scale. Key: High Financial Motivation (+1 SD), Low Financial Motivation (–1 SD)