Public Acceptability in the UK and USA of Nudging to Reduce Obesity: The Example of Reducing Sugar-Sweetened Beverages Consumption

Abstract

Background: "Nudging"-modifying environments to change people's behavior, often without their conscious awareness-can improve health, but public acceptability of nudging is largely unknown.

Methods: We compared acceptability, in the United Kingdom (UK) and the United States of America (USA), of government interventions to reduce consumption of sugar-sweetened beverages. Three nudge interventions were assessed: i. reducing portion Size, ii. changing the Shape of the drink containers, iii. changing their shelf Location; alongside two traditional interventions: iv. Taxation and v. Education. We also tested the hypothesis that describing interventions as working through non-conscious processes decreases their acceptability. Predictors of acceptability, including perceived intervention effectiveness, were also assessed. Participants (n = 1093 UK and n = 1082 USA) received a description of each of the five interventions which varied, by randomisation, in how the interventions were said to affect behaviour: (a) via conscious processes; (b) via non-conscious processes; or (c) no process stated. Acceptability was derived from responses to three items.

Results: Levels of acceptability for four of the five interventions did not differ significantly between the UK and US samples; reducing portion size was less accepted by the US sample. Within each country, Education was rated as most acceptable and Taxation the least, with the three nudge-type interventions rated between these. There was no evidence to support the study hypothesis: i.e. stating that interventions worked via non-conscious processes did not decrease their acceptability in either the UK or US samples. Perceived effectiveness was the strongest predictor of acceptability for all interventions across the two samples.

Conclusion: In conclusion, nudge interventions to reduce consumption of sugar-sweetened beverages seem similarly acceptable in the UK and USA, being more acceptable than taxation, but less acceptable than education. Contrary to prediction, we found no evidence that highlighting the non-conscious processes by which nudge interventions may work decreases their acceptability. However, highlighting the effectiveness of all interventions has the potential to increase their acceptability.

Fig 1. Barplots of the overall acceptability scores per intervention and country.

Fig 2. Proportion of participants (99.807% bootstrap percentile CIs) rating as acceptable each intervention, by country. Percentages significantly different from 50% appear in green.

Percentages not significantly different from 50% appear in red. As 35 comparisons are performed in the analysis corresponding to Figs 2, 3 and 4, a correction for multiple testing which takes into account the dependencies in the data was used, leading to CI levels of 99.807%.

Fig 3. Difference in acceptability (99.807% bootstrap percentile CIs) for each combination of intervention within each country.

Percentages significantly different from 0 appear in green. Percentages not significantly different from 0 appear in red. As 35 comparisons are performed in the analysis corresponding to Figs 2, 3 and 4, a correction for multiple testing which takes into account the dependencies in the data was used, leading to CI levels of 99.807%.

Fig 4. Difference in acceptability (99.807% bootstrap percentile CIs) for each intervention between the US and the UK.

Percentages significantly different from 0 appear in green. Percentages not significantly different from 0 appear in red. As 35 comparisons are performed in the analysis corresponding to Figs 2, 3 and 4, a correction for multiple testing which takes into account the dependencies in the data was used, leading to CI levels of 99.807%.