Policy-makers show an increasing interest in ‘nudges’ – behaviorally informed interventions that steer people in certain directions but that maintain freedom of consumer choice. Despite general evidence, across nations, of majority approval of nudges involving health, safety, and the environment, little evidence has surfaced about which population groups support nudges and nudging. In particular, the present study investigates why consumers in selected European countries differ markedly in their attitudes toward behavioral nudges as policy tools employed by their national governments. The research question is derived from the findings of an earlier study (Reisch and Sunstein 2016) that compared the approval rates of 15 nudges in European countries. The nudges are related to health, energy, and social welfare decisions. Results showed that, of the 15 nudges an average of 7.8 nudges in Denmark, 8.4 in Hungary, 10.3 in the United Kingdom, to 10.7 in Italy were approved by simple majority. These are significant differences in approval rates and they motivated the question of why they differ across these European countries. We examined a long list of individual, household, and geographic characteristics to answer this question.

Which individual, household, and geographic characteristics are related to the approval of nudges in each of the four countries?

The associations of overall approval with household income, gender, and geographic characteristics were particularly strong. Household income was associated with approval in three of the four countries. The consistently positive relationship of higher household income and nudge approval in the United Kingdom and Italy aligns with earlier findings in the nudges literature (Diepeveen et al. 2013). It also parallels marketing research showing that households of higher socio-economic status are more likely to adopt nudges and are in general more adoptive of innovations (Woersdorfer and Kaus 2011, Laukkanen 2016, Rivers, Shenstone-Harris, and Young 2017). In contrast, the role of income is different in the Danish sample, where nudge approval was related to lower income. Correlation analysis showed that the lowest Danish income group is particularly strongly and significantly correlated with the youngest age group (below 30 years of age), smaller household sizes, and lower educational attainment, compared to the British and Italian samples. We speculate that this finding may reflect a higher level of trust in the government and its welfare policies among lower-income, younger, and lower-educated individuals in Denmark.

Male gender was negatively associated with approval in Hungary, the United Kingdom and, marginally significantly, in Italy. This finding previously emerged in our baseline study (Reisch and Sunstein 2016) and was shown in other multi-country studies (Diepeveen et al. 2013). It confirms the well-documented gender differences in the adoption of certain innovations (Venkatesh, Morris, and Ackerman 2000).

Our findings that the approval rates of a bundle of nudges depend on distinct population characteristics indicate that nudge-based policy interventions will benefit from testing and targeting. The European Joint Research Center’s behavioral group has rightly called for an empirical ‘test-learn-adapt-share’ approach in behavioral insights-based policies that takes into account the targets as well as the socio-economic and cultural settings (Lourenço et al. 2016). Similar suggestions on the policy process have been put forward recently by the OECD (2017) and The World Bank (2015), among others.

Which individual, household, and geographic characteristics are related to approval of System 1 and System 2 nudges? Are System 1 nudges more polarizing compared to System 2 nudges?

A nudge can be labeled ‘System 1’ if it targets automatic, intuitive, often unconscious processes and passive decision-making, or ‘System 2’ if it targets deliberate, thoughtful, rule-based evaluation and approval (Marchiori, Adriaanse, and Ridder 2017). Prominent examples of System 1 nudges are graphic warnings on cigarette boxes and default rules. Statistical information and factual disclosures, such as calorie labels and information campaigns, are System 2 nudges (Sunstein 2016). Our findings suggest that in less high approval countries, if System 1 nudges are to be introduced, they may benefit from focused efforts to explain and justify such interventions. In high-approval countries, our findings indicate lower controversy about System 1 nudges and higher approval among a wider range of income and age groups of System 2 nudges. To that extent, our findings are in line with literature that documented higher approval for System 2 nudges (Jung and Mellers 2016, Sunstein 2016). Our findings highlight, however, that this approval can be based on either lower controversy (in less high approval countries) or a higher number of positive relationships (in high-approval countries).

In this respect, implications for consumer policy are twofold. In contrast to an earlier multi-country study (Diepeveen et al. 2013), the current study found that approval of nudges is not necessarily a function of the influence of a country’s democratic or authoritarian leadership. Rather, lesser or higher approval of nudges might be an independent product of public opinion, taken simply as such.

When examining the 15 nudges, is overall approval in a country related to higher polarization, and is higher polarization related to national identities or concerns?

Our study documents that less high approval in a country is not necessarily related to higher controversy. While it is true for Denmark, the findings for Hungary indicate that relatively lower approval can be associated with lower levels of polarization in the population. We note as well that Hungary had a smaller number of public institutions applying behavioral insights to policy. A recent report listed six public institutions in Hungary, compared to 15 in Denmark (Lourenço et al. 2016). Similarly, the current study documents that high approval of nudges can be associated with both relatively higher (U.K.) and lower polarization (Italy).

In each country, one of the 15 nudges was the most polarizing nudge with regard to the count of significant predictor variables – and it was a different nudge in each country. The high-controversy nudges tended to be associated with current public policy concerns in the countries. Meat-free day was the most polarizing nudge in Denmark, possibly reflecting public discourse about the role of pork meat in Danish food culture (Agence France-Presse 2016). A ‘traffic light’ system for food was the most polarizing nudge in Hungary, possibly reflecting consumer concern about a Public Health Tax on Food Products introduced in Hungary in 2011, which led to a 29% price increase (OECD 2014). Placing labels on products that have unusually high levels of salt was the most polarizing nudge in the U.K. and may indicate public unease about proposed taxation of sodium-rich food (Public Health England 2016). In Italy, the most polarizing nudge was a public education campaign to reduce childhood obesity, reflecting a widespread public concern about Italy being one of the OECD countries with the highest levels (OECD 2015). (Note, however, that under our definitions, a polarizing nudge might also have high approval rates; for example, men and women might be polarized even if 70 percent of men approve and 95 percent of women do so).


The present research provides highly suggestive evidence that for nudges, approval rates are related to individual, household, and geographic characteristics. The role of these characteristics varies across nudges and nations. For that reason, it should be plain that generalizations are hazardous. To be sure, some larger patterns emerge, with strong majority support for a wide range of consumer-related nudges, supplying a kind of ‘green light’ for officials. But many of the patterns are more specific, showing noteworthy and unanticipated differences across nations.

Public officials are inevitably interested in knowing whether their interventions will receive public approval, and if so, whether some groups will be more supportive than others. Our findings offer a more refined, and in some ways surprising, understanding of likely popular reactions to nudges. They also provide guidance about when targeted explanations and justifications may be both useful and important.


Cäzilia Loibl is Associate Professor at The Ohio State University, Department of Human Sciences

Cass R. Sunstein is the Robert Walmsley University Professor at Harvard Law School

Julius Rauber is Project Manager Consumer Research at the Institute for Consumer Policy, Berlin

Lucia A. Reisch is Professor at the Copenhagen Business School, Department of Management, Society and Communication