Incremental versus saturation hypotheses for behavioral nudge in reducing sugar consumption

Objective: This field experiment examined the efficacy of a behavioral nudge intervention towards lowering sugar intake in Indonesia. Specifically, two competing hypotheses were tested as to whether behavioral nudge played an additive role (i.e., the Incremental Hypothesis) or contributed to a ceiling effect (i.e., the Saturation Hypothesis) alongside social context and competition in a multimodal intervention program. Method: This field experiment used a three-factorial mixed design involving 403 Indonesian participants based on power statistical analysis: 2 (sugar content nudge: lower sugar tea vs. regular sugar tea default) × 2 (social context: individual vs. group) × 2 (competition: absent vs. present). Results: Nudging was the most powerful intervention in reducing sugar intake, but its effectiveness might be attenuated by social loafing even within Indonesia’s collectivist culture. Competition did not work synergistically with nudging but was effective under the nonnudge condition. Conclusion: Our results are consistent with those of previous research showing that behavioral nudging has a stronger impact on behavioral change than nonnudge strategies. Contrary to some previous research, people in collectivist Indonesia did engage in social loafing: achievement motivation is not necessarily enhanced in a team of people in a collectivist culture. The Nudge × Competition interaction supports the saturation hypothesis in favor of behavioral nudging: using more than one intervention, when a potent strategy such as nudging is present, might result in diminishing returns that could reduce the overall benefit-cost profile of such multimodal intervention programs.