Eight Misconceptions About Nudges


Cass R. Sunstein


Résumé

Il existe de nombreuses idées erronées sur les nudges et leur usage, et certaines d’entre elles sont très répandues. Par exemple, certaines personnes pensent que les nudges sont manipulateurs, qu’ils sont cachés ou dissimulés, qu’ils sont difficiles à définir, qu’ils portent atteinte à l’autonomie, qu’ils sont fondés sur une confiance excessive dans le gouvernement, qu’ils exploitent les biais comportementaux, qu’ils dépendent de la croyance que les êtres humains sont irrationnels et qu’ils ne fonctionnent qu’à la marge, qu’ils n’affectent pas les structures et qu’ils ne peuvent pas accomplir grand-chose. Il s’agit là d’erreurs. Les nudges sont généralement transparents plutôt que dissimulés ou sous forme de manipulation ; les nudges ne sont pas difficiles à définir ; les nudges respectent toujours, et souvent encouragent, l’autonomie ; parce que les nudges insistent sur la préservation de la liberté de choix, ils n’accordent pas une confiance excessive au gouvernement ; de nombreux nudges sont éducatifs, et même lorsqu’ils ne le sont pas, ils tendent à rendre la vie plus simple et plus navigable ; et certains nudges ont un impact assez important. Il est vrai que pour d’innombrables problèmes, les nudges sont à peine suffisants. Ils ne peuvent pas éliminer la pauvreté, le chômage et la corruption. Mais en soi, toute initiative individuelle – qu’il s’agisse d’une taxe, d’une subvention, d’un mandat ou d’une interdiction – a peu de chances de résoudre les grands problèmes. Les atténuer est déjà une réussite.

Abstract

There are many misconceptions about nudges and nudging, and some of them are widespread. For example, some people believe that that nudges are manipulative; that nudges are hidden or covert; that nudges are difficult to define; that nudges are an insult to human agency; that nudges are based on excessive trust in government; that nudges exploit behavioral biases; that nudges depend on a belief that human beings are irrational; and that nudges work only at the margins, do not affect structures, and cannot accomplish much. These are mistakes. Nudges are generally transparent rather than covert or forms of manipulation; nudges are not difficult to define; nudges always respect, and often promote, human agency; because nudges insist on preserving freedom of choice, they do not put excessive trust in government; many nudges are educative, and even when they are not, they tend to make life simpler and more navigable; and some nudges have quite large impacts. It is true that for countless problems, nudges are hardly enough. They cannot eliminate poverty, unemployment, and corruption. But by itself, any individual initiative – whether it is a tax, a subsidy, a mandate, or a ban – is unlikely to solve large problems. Denting them counts as an achievement.


How to cite :

Sunstein, Cass R., 2023. « Eight Misconceptions About Nudges ». Nomopolis 1.

Nudges are private or public initiatives that steer people in particular directions but that also allow them to go their own way (Thaler & Sunstein 2008; Thaler 2015). A reminder is a nudge; so is a warning. A GPS device nudges; a default rule, automatically enrolling people in some program, is a nudge (Ebeling & Lotz, 2015). To qualify as a nudge, an initiative must not impose significant material incentives (including disincentives).

Nudges fall in two general categories: the educative and the architectural. Educative nudges include warnings, reminders, and disclosure of information (such as calorie labels, allergy warnings, text reminders that bills are due, and fuel economy labels). Architectural nudges include automatic enrollment, mandatory choice, prompted choice, simplification (as in “sludge reduction”), and design of websites, forms, or in-person stores so as to highlight, and draw attention to, certain options. Whether educative or architectural, nudges have often been found to have significant effects on outcomes and to be highly cost-effective (Benartzi et al., 2017).

A subsidy is not a nudge; a tax is not a nudge; a fine or a jail sentence is not a nudge. To count as such, a nudge must preserve freedom of choice. If an intervention imposes significant material costs on choosers, it might of course be justified, but it is not a nudge. Some nudges work because they inform people; other nudges work because they make certain choices easier and more salient; still other nudges work because of the power of inertia and procrastination. Some nudges target individuals (as in a calorie label); some nudges target companies (as in the Toxic Release Inventory or the Greenhouse Gas Inventory); some nudges attempt to produce structural changes (Sunstein, 2023).

My goal here is not to celebrate what has been learned, or to engage the many productive objections, clarifications, and refinements (Thaler & Sunstein, 2021; Benartzi et al., 2017; Goldin & Lawson, 2016; Allcott & Kessler, 2015; Goldin 2015; Rebonato, 2012), but more modestly to catalogue ten common mistakes and misconceptions. Unfortunately, they continue to divert attention both in the public domain and in academic circles, and hence to stall progress.

Without further ado[1]:

I. NUDGES ARE MANIPULATIVE

Some people have objected that nudges are a form of manipulation (Conly 2010). But why? What definition of manipulation supports that objection? Are people manipulated if they are warned that certain foods contain shellfish or nuts? Are they manipulated if they are told that if they take more than the recommended dosage of some medicine, something bad might happen?  Are people manipulated if they are given information about the fuel economy of the motor vehicles that they might buy? A GPS device does not manipulate people (at least most GPS devices do not do that). If people are reminded that they have a doctor’s appointment next Thursday, no one is manipulating them.

To be sure, we could imagine a graphic warning about opioid addiction, or about the use of cell phones while driving, that would create immediate fear or revulsion, or intensely engage people’s emotions; it might be objected that nudges of this kind count as a form of manipulation (Barnhill, 2014). To know whether they do, we need a definition of manipulation (Sunstein, 2015). To make a (very) long and complex story short, philosophers and others have generally converged on the view that an action counts as manipulative if it bypasses people’s capacity for rational deliberation (ibid.; Barnhill, 2014).  On any view, most nudges do not come close to qualifying. True, some imaginable nudges might cross the line, but that is very different from saying that nudges are manipulative as such.

II. NUDGES ARE HIDDEN AND COVERT

Some people have argued that mandates, bans, and taxes have one advantage: They are transparent (Glaeser, 2006). People know what they are. No one is fooled. By contrast, nudges are covert and in that sense sneaky, a form of trickery (ibid). They affect people without their knowledge.

For countless nudges, this objection is impossible to understand. A GPS device nudges, and it is entirely transparent. Or consider educative nudges. Labels, warnings, and reminders are not exactly hidden; if they are, they will not work. If a cafeteria offers calorie labels, it is not hiding what it is doing. If people receive a text message, saying that their medicine is ready at the pharmacy, nothing is hidden. When an employer automatically enrolls employees into a savings plan, subject to opt out, employees are told what is happening; nothing is covert. (If it is, there is a problem; the right to opt out should be clear.)

Why, then, have intelligent people objected that nudges are hidden and covert? Is there anything at all to that objection? One possibility is that when people participate in a randomized controlled trial, they may not be informed of that fact. (A randomized trial might not work if people are told about the various conditions.) But I suspect that the real answer is that some nudges work even though those who are affected by them do not focus on them, or even think about them (Rebonato, 2012) While such nudges are hardly hidden, people may be unaware of them, or at least unaware of their purposes and effects.

For example, a cafeteria might be designed so that the healthy foods are most visible and placed first, and people might choose them for that very reason. Such a design is not hidden – on the contrary, it should be obvious — but people may not be aware that their cafeteria has been designed so as to promote healthy choices. To be sure, they know that the fruits are more visible than the brownies, but they might not know why, and their decision to select a fruit might be quick and automatic rather than reflective. Or people might not think much about the default rules that come with (say) an agreement with a rental car company. If people are automatically enrolled into some kind of insurance plan and allowed to opt out, they might say, “yeah, whatever,” and simply go along with the default. (By the way, Nudge identified only one new heuristic, and it’s that: the “yeah, whatever” heuristic.)

In that sense, it is not false to say that some nudges can work even if or perhaps because people are unaware that they are being nudged. Note, however, that emerging evidence finds that the effects of such nudges are not diminished even if people are told that nudging is at work (Michaelsen and Sunstein, 2023). Though research continues, transparency about the existence and justification of default rules appears not to reduce their impact in general (ibid.; Bruns et al. 2016; Loewenstein et al. 2015). For some people, such clarity may even increase that impact, by amplifying the informational signal that some default rules offer (Michaelsen and Sunstein, 2023; Mackenzie et al 2006). On plausible assumptions, drawing attention to the healthy design of a cafeteria will actually increase the effect of that design, because it will convey valuable information. (To be sure, it may produce “reactance” in some consumers.)

III. NUDGES ARE ILL-DEFINED; IT IS NOT EVEN CLEAR WHAT THEY ARE

Some people have questioned whether nudges are well-defined. Indeed, there seems to be a small industry of people (or is it ChatGPT?), spending a great deal of time struggling with the supposed definitional problem — arguing that we cannot know what nudges are, that they may or may not include educative interventions, that they may or may not include taxes and fines, and that they may or may not include interventions that are aimed at reducing externalities. Some of this work opposes nudges to regulation, even though many nudges are regulations (as in the case of a mandatory fuel economy regulation).

People can, of course, define nudges however they want, but there is a standard definition, and it is probably best to stick with it. One more time: A nudge is an intervention that affects behavior while preserving freedom of choice (without significantly altering material incentives, and without imposing a mandate or a ban). An educative nudge is a nudge. A warning is a nudge. A default rule is a nudge. An effort to reduce externalities is an externality-reducing nudge. There is no reason to manufacture a definitional controversy.[2]

IV. NUDGES ARE AN INSULT TO HUMAN AGENCY

In free societies, people are treated with respect. They are allowed to go their own way. Some people object that nudges are troublesome because they treat people as mere objects for official control (cf. Waldron 2014).

The objection is off the mark. One of the main points of nudging is to preserve freedom of choice — and thus to maintain people’s capacity for agency. We have seen that many nudges are self-consciously educative, and hence they strengthen that very capacity; consider calorie labels, or warnings about risks associated with certain products. With information, warnings, and reminders, people are in a better position to choose their own way. Noneducative nudges, such as uses of healthy choice architecture at cafeterias or in grocery stores, also allow people to choose as they wish.

Perhaps it could be argued that if the goal is to promote agency, default rules are problematic. But because such rules are omnipresent in human life, it is not easy to make that argument convincing (Michaelsen and Sunstein, 2023). Would it make sense to excise default rules from the law of contract? To say that employers, hospitals, and banks are forbidden from using default rules? In practice, what would that even mean? Those who are inclined to reject default rules out of respect for individual agency would do well to ponder the countless contexts in which such rules make life simpler and easier to navigate. (On the immense importance of navagibility, more in a moment.)

A narrower argument would be that in certain settings, those who prize agency should insist on active choosing in preference to default rules. In Nudge, Thaler and I make exactly that argument in the context of organ donation (Thaler and Sunstein, 203), urging that when people receive drivers’ licenses, they ought to be asked whether they want to be organ donors. In some settings, active choosing is indeed better.

Note, however, that sometimes people cannot easily choose (because they lack bandwidth or expertise) or simply do not want to choose (Sunstein, 2015); they consider default rules to be a blessing. One reason is that people have limited time and attention, and they exercise their own agency by relying on default rules. If we aim to respect individual agency, we will often be inclined to favor those rules for that very reason (Sunstein 2017b). It is a complex question when active choosing should be preferred to default rules, or vice-versa. A simple framework, on which much more would have to be said: Inquire into the costs of decisions and the costs of errors.

V. NUDGES ARE BASED ON EXCESSIVE TRUST IN GOVERNMENT

The most intuitive objection to nudging is rooted in fear of government. To put that objection in its sharpest form: Suppose that public officials are incompetent, self-interested, reckless, or corrupt. Suppose that your least favorite leaders are or will be in charge. Would you want them to nudge? Or suppose that you are keenly alert to public choice problems, emphasized by James Buchanan and his followers, or “the knowledge problem,” emphasized by Friedrich Hayek and his followers. If interest groups are able to push government in their preferred directions, and if public officials lack crucial information, then you might insist: Do not nudge! Reliance on private markets might seem far better (Glaeser, 2006).

Indeed, behavioral science itself might be taken to put this conclusion in bold letters. There is no reason to think that public officials are immune to behavioral biases. In a democratic society, the electoral connection might mean that they will respond to the same biases that affect ordinary people (Kuran and Sunstein 1999). To be sure, structural safeguards might help, especially if they ensure a large place for technocrats, insistent on science and on careful attention to costs and benefits. But in any real-world polity, behavioral distortions are difficult to avoid.

These are fair and important points, but if they are taken as an objection to nudging, they run into a logical problem: a great deal of nudging is inevitable. So long as government has offices and websites, it will be nudging. If the law establishes contract, property, and tort law, it will be nudging, if only because it will set out default rules, which establish what happens if people do nothing.  As Hayek himself wrote, the task of establishing a competitive system provides “indeed a wide and unquestioned field for state activity,” for “in no system that could be rationally defended would the state just do nothing. An effective competitive system needs an intelligently designed and continuously adjusted legal framework as much as any other” (Hayek, 1943).

As Hayek understood, a state that protects private property and that enforces contracts has to establish a set of prohibitions and permissions, including a set of default entitlements, establishing who has what before bargaining begins. For that reason, it is pointless to exclaim, “do not nudge!” – at least if one does not embrace anarchy.

The second answer to those who distrust government is that because nudges maintain freedom of choice, they offer a safety valve against official error. Those who favor nudges are keenly alert to the public choice problem and the knowledge problem, and to the possibility that public officials will show behavioral biases. Many of them are influenced by Buchanan and (especially) Hayek. If one distrusts government, the real focus should be on mandates, bans, subsidies, and taxes. To be sure, nudges ought not to be free from scrutiny, but they should be a relatively low priority.

It is true, of course, that some nudging is optional. Government can warn people about smoking, opioid addiction, and distracted driving, or not.  It can seek to protect consumers against deception and manipulation, or not. It can undertake public education campaigns, or not. If you think that government is entirely untrustworthy, you might want it to avoid nudging whenever it can. In the abstract, that position cannot be ruled out of bounds. Public choice problems, and the knowledge problem, are real and important. On highly pessimistic assumptions about the capacities and incentives of public officials, and highly optimistic assumptions about the capacities and incentives of those in the private sector, nudging should be minimized (Glaeser, 2006). But private actors nudge, and sometimes it is very much in their interest to exploit cognitive biases, thus causing serious harm to countless people (Akerlof and Shiller, 2016). Would it be a good idea to forbid public officials from taking steps to reduce smoking and distracted driving? In any case, the track record of real-world nudging includes impressive success stories, if success is measured by cost-effectiveness (Benartzi et al., 2017).

Importantly, nudges, like other interventions from such officials, should be constrained by democratic requirements, including transparency, public debate, and independent monitoring (including continuing evaluation of how they work in practice). Constraints of this kind can reduce the risks (without eliminating them). The fundamental point is that those risks are far larger with other tools, above all mandates and bans.

VI. NUDGES EXPLOIT BEHAVIORAL BIASES

Some people object that nudges “exploit” or “take advantage of” behavioral biases. Indeed, some people define nudges as exploitation of behavioral biases (Rebonato 2010). That does sound nefarious. But the objection is mostly wrong, and while (again) people can define terms however they wish, this particular definition is a recipe for confusion.

Many nudges make sense, and help people, whether or not a behavioral bias is at work. A GPS is useful for people who do not suffer from any such bias. Disclosure of information is helpful even in the absence of any bias. A default rule simplifies life and can therefore be a blessing whether or not a behavioral bias is involved.

As the GPS example suggests, many nudges have the goal of increasing navigability – of making it easier for people to get to their preferred destination. Such nudges stem from an understanding that life can be either simple or hard to navigate, and a goal of helpful nudging is to promote simpler navigation. I wish that Nudge had made this point clearer, and had connected nudging to the central idea of navigability.

At the same time, it is true that some nudges counteract behavioral biases, and that some nudges work because of behavioral biases. For example, many human beings tend to suffer from present bias, which means that they give relatively little weight to the long term; many of us suffer from unrealistic optimism, which means that we tend to think that things will turn out better for us than statistical reality suggests. Some nudges try to counteract present bias and optimistic bias – as, for example, by emphasizing the long-term risks associated with smoking and drinking, or by suggesting the importance of retirement planning. Similarly, default rules work in part because of inertia, which undoubtedly counts as a behavioral bias. But it is misleading — a form of rhetoric, in the not-good sense — to suggest that nudges “exploit” such biases.

VII. NUDGES WRONGLY ASSUME THAT PEOPLE ARE IRRATIONAL

Some critics object that nudges are based on a belief that human beings are “irrational,” which is both insulting and false.[3] This objection takes different forms.

In one form, the objection is that while people rely on simple heuristics and rules of thumb, nothing is wrong with that; those heuristics and those rules work well, and so nudging is not needed, and can only make things worse. In another form, the objection urges that the whole idea of nudging is based on weak psychological research and on an assortment of supposed laboratory findings that do not hold in the real world. In yet another form, the objection is that people can and should be educated or “boosted” rather than nudged. In what seems to me its best form, the objection urges that people’s utility functions are complex and that outsiders may not understand them; what seems to be “irrationality” may be the effort to trade off an assortment of goals (Rebonato 2010).  A mundane example: People might eat fattening foods not because they suffer from present bias, but because they greatly enjoy those foods. A less mundane example: People might fail to save for retirement not because they suffer from optimistic bias, but because they need the money now.

No one should doubt that heuristics generally work well (that is why they exist); but they can also misfire. When they do, a nudge can exceedingly helpful. Many nudges are developed with reference to well-established behavioral findings, demonstrating that people depart from perfect rationality. For example, default rules work in part because of the power of inertia (Johnson and Goldstein 2013); reminders are necessary and effective in part because people have limited attention; information will be more likely to influence behavior if it is presented in a way that is attentive to people’s imperfect information-processing capacities. These and other claims are based on evidence, both in the laboratory and the real-world. (It is always possible that they will be found to be imprecisely stated, or wrong in important settings.) But those who embrace nudges do not use the term “irrationality.” In fact they abhor it; “bounded rationality” is much better. Nor does anyone doubt that education can work. As I have emphasized, many nudges are educative. More ambitious educative efforts, such as efforts to help people to assess risks and to teach statistical literacy, are usually complements to nudges, and rarely substitutes or alternatives. Boosts and nudges can march hand-in-hand.

It is also true (and exceedingly important) that people’s utility functions are complex and that outsiders might not understand them; that is one reason that nudgers insist on preserving freedom of choice. To the extent that nudging is inevitable, it is pointless to contend that because of the complexity of people’s utility functions, nudging should be avoided. To the extent that nudging is optional, it should be undertaken with an appreciation of the risk of error and with careful efforts to ensure that it promotes, and does not undermine, people’s welfare. A GPS device does not decrease welfare. In general, information about health risks and potential financial burdens should increase welfare (Agarwal et al., 2013).

Of course nudges must be tested to ensure that they are doing what they are supposed to do (Halpern 2015; Thaler 2015). Some nudges fail. When they do, the right conclusion may be that freedom worked – or that we should nudge better (Sunstein 2017a).

VIII. NUDGES WORK ONLY AT THE MARGINS; THEY ARE “MERE TWEAKS,” AND THEY CANNOT ACHIEVE MUCH

If experts are asked to catalogue the world’s major problems, many of them would single out poverty, malnutrition and hunger, unemployment, corruption, diseases, terrorism, and climate change. On one view, nudges are an unfortunate distraction from what might actually help. With an understanding of nudging, we might have some fresh ideas about how to tweak letters from government to citizens, producing statistically significant increases in desirable behavior. But that is pretty small stuff. If behavioral economists want to make a contribution, shouldn’t they focus on much more important matters? Shouldn’t they focus on structures, rather than individual behavior? A related objection is that many nudges have no effect at all. If we compiled a long list of nudges over the past twenty years, including those in studies that were never published, we might find that the average effect is zero, or close to it.

It is important to say that behaviorally informed approaches are hardly limited to nudges; mandates, bans, and incentives may well have behavioral justifications (Sunstein, 2023; Thaler and Sunstein, 2022; Thaler, 2017; Loewenstein and Chater, 2017; Conly 2010). The policy program of behavioral science is not exhausted by nudges (Thaler 2017; Sunstein, 2023). In any case, nudges often affect structures, not individual behavior (ibid.) It is also true that some nudges produce only modest changes. But in multiple domains, nudges have proven far more cost-effective than other kinds of interventions, which means that per dollar spent, they have had a significantly larger impact (Benartzi et al., 2017).

By any measure, the consequences of some nudges are not properly described as modest. As a result of automatic enrollment in free school meals programs, more than 11 million poor American children are now receiving free breakfast and lunch during the school year.  Credit card legislation, enacted in 2010, is saving American consumers more than $10 billion annually; significant portions of those savings come from nudges and nudge-like interventions (Agarwal et al. 2013). With respect to savings, automatic enrollment in pension programs has produced massive increases in participation rates (Thaler and Sunstein, 2023; Chetty et al., 2012; Thaler, 2016).

Suppose, however, that if we made a very long list of nudges, we found an average effect size of zero, or close to it. What would follow from that? Not much. It might be that if we made a very long list of subsidy programs, tax incentive programs, criminal penalties, or even medicines, over a long period of time, we would find an average effect size of zero, or close to it. (Some criminal penalties are small; some are not enforced; many medicines do not work.) As we have seen, nudges take multiple different forms, and it would be easy to design nudges that would be expected to have no effect at all (a confusing, nonsalient warning, for example). For obvious reasons, many unpublished studies find little or no effect. Different populations, different kinds of nudges, and different levels of salience or receptivity will matter. (Most people who go fishing might catch no fish.) We need to learn much more about all this.

No one should doubt that new nudges, now in early stages or under discussion, could have a major impact. If the goal is to increase tax compliance, nudges could help. If the goal is to combat discrimination, nudges could help. If the goal is to reduce greenhouse gas emissions, automatic enrollment in green energy can have large effects (Ebeling and Lotz, 2015; Pichert and Katsikopoulos, 2008). The Earned Income Tax Credit is probably the most effective anti-poverty program in the United States, but many eligible people do not take advantage of it. Automatic enrollment would have large consequences for the lives of millions of people. In the United States alone, automatic voter registration could turn millions of people into voters. Sludge reduction is extremely important (Thaler and Sunstein, 2023). With respect to the world’s most serious problems, the use of nudges remains in its preliminary stages. We will see far more in the future, and the impact will not be small.

It is true, of course, that for countless problems, nudges are hardly enough. They cannot eliminate poverty, unemployment, and corruption. But by itself, any individual initiative – whether it is a tax, a subsidy, a mandate, or a ban – is unlikely to solve large problems. Denting them counts as an achievement.

References

Agarwal S, Chomsisengphet S, Mahoney N, Stroebel J. 2013. Regulating Consumer Financial Products: Evidence from Credit Card. Work. Pap., NBER

Akerlof, George and Robert Shiller. 2016. Phishing for Phools. Princeton: Princeton University Press.

Allcott, Hunt and Judd B. Kessler. 2015. The Welfare Effects of Nudges: A Case Study of Energy Use Social Comparisons. NBER, Working Paper 21671

Barnhill, Anne. 2014. What is Manipulation? in Manipulation: Theory and Practice 50, 72 (Christian Coons and Michael Weber eds.).

Benartzi, Shlomo  et al. 2017. Should Governments Invest More in Nudging? Psychological Science, available at http://journals.sagepub.com/doi/abs/10.1177/0956797617702501

Bruns, Hendrik et al., Can Nudges Be Transparent and Yet Effective? (2016). Available at https://papers.ssrn.com/sol3/papers.cfm?abstract_id=2816227

Chetty, Raj, John N. Friedman, Soren Leth-Petersen, Torben Nielsen and Tore Olsen (2012). Active vs. Passive Decisions and Crowdout in Retirement Savings Accounts: Evidence from Denmark, available at http://www.nber.org/papers/w18565

Conly, Sarah. Against Autonomy. 2013. Oxford: Oxford University Press.

Ebeling, F., & Lotz, S. (2015). Domestic uptake of green energy promoted by opt-out

tariffs. Nature Climate Change, 5 (9), 868-871.Retrieved from: doi: 10.1038/nclimate2681

Fryer Jr, R. G., Levitt, S. D., List, J., & Sadoff, S. (2012). Enhancing the efficacy of teacher incentives through loss aversion: A field experiment (No. w18237). National Bureau of Economic Research. Retrieved from: DOI: 10.3386/W18237

Gigerenzer, Gerd. 2016. On the Supposed Evidence for Libertarian Paternalism. Review of Philosophy and Psychology 3: 361.

Glaeser, Edward. 2006. Paternalism and Policy. University of Chicago Law Review 73: 133-56.

Goldin, Jacob and Nicholas Lawson. 2016. Defaults, Mandates, and Taxes: Policy Design with Active and Passive Decision-Makers. American Law & Economics Review 18: 438.

Goldin, Jacob. 2015. Which Way To Nudge? Yale Law Journal 125: 227.

Halpern, David. 2015. Inside the Nudge Unit. London: Ebury Press,

Hayek, Friedrich. 1943. The Road to Serfdom. Chicago: University of Chicago Press.

Homonoff, T. A. (2013). Can small incentives have large effects? The impact of taxes versus bonuses on disposable bag use. Industrial Relations Section, Princeton University Working Paper, (575). Retrieved from: http://arks.princeton.edu/ark:/88435/dsp014q77fr47j

Kuran, Timur and Cass R. Sunstein. 1999. Availability Cascades and Risk Regulation Stanford Law Review 51: 683-762.

Johnson, Eric and Daniel Goldstein (2013). Decisions by Default. In: Eldar Shafir (Ed.). Behavioral Foundations of Policy, Chapter 24, pp. 417–427. Princeton: Princeton University Press.

Loewenstein, George and Chater, Nick. 2017. Putting Nudges in Perspective. Behavioral Public Policy 1: 26-53.

Loewenstein, George, Cindy Bryce, David Hagmann, & Sachin Rajpal (2015). Warning: You are about to be nudged. Behavioral Science & Policy 1: 35-42.

Michaelsen, Patrick and Cass R. Sunstein (2023). Default Nudges.  London: Palgrave.

McKenzie, C. R., Liersch, M. J., & Finkelstein, S. R. (2006). Recommendations implicit in policy defaults. Psychological Science, 17(5), 414-420. doi: 10.1111/j.1467-9280.2006.01721.x

Pichert, Daniel and Konstantinos V. Katsikopoulos (2008). Green Defaults: Information Presentation and Pro-environmental Behaviour. Journal of Environmental Psychology. 28: 63–73.

Rebonato, Riccardo (2012). Taking Liberties. London: Palgrave.

Reisch, Lucia and Cass R. Sunstein. 2016. Do Europeans Like Nudges? Judgment and Decision Making 11: 310-25.

Sunstein, Cass R. (2015). The Ethics of Influence. Cambridge: Cambridge University Press.

Sunstein, Cass R. (2017a). Nudges That Fail. Behavioral Public Policy 1: 4-25.

Sunstein, Cass R. (2017b). Human Agency and Behavioral Economics. London: Palgrave.

Sunstein, Cass R. and Lucia Reisch (2016). The Economics of Nudge (four volumes). Routledge.

Sunstein, Cass R. (2023). Behavioral Science In Government. Administrative Law Review (forthcoming).

Thaler, Richard. 2017. Much Ado About Nudging. Behavioral Public Policy Blog, available at https://bppblog.com/2017/06/02/much-ado-about-nudging/

Thaler, Richard. Misbehaving. 2015. New York: Norton.

Thaler, Richard H. & Cass R. Sunstein (2021). Nudge: The Final Edition. New Haven: Yale University Press.

Thaler, Richard H. & Cass R. Sunstein (2008). Nudge: Improving decisions about health, wealth, and happiness. New Haven: Yale University Press.

Waldron, Jeremy. 2014. It’s All For Your Own Good, New York Review of Books, available at http://www.nybooks.com/articles/archives/2014/oct/09/cass-sunstein-its-all-your-own-good/..

[1] I will have something to say about definitional questions; in recent years, a great deal of work has been devoted to those questions. My hope is that the opening sentence of this essay is clear enough, at least if it is informed what immediately follows it. In the same vein, see Nudge, p. 8: “a nudge, as we shall use the term, is any aspect of the choice architecture that alters people’s behavior in a predictable way without forbidding any options or significantly changing their economic incentives.”

[2] I do not deny that we can find borderline cases. Is a portion size requirement a nudge? That is not entirely obvious.

[3] The least lovely, and the most bizarre, version of this claim comes from a German psychologist: “The interest in nudging as opposed to education should be understood against the specific political background in which it emerged. In the US, the public education system is largely considered a failure, and the government tries hard to find ways to steer large sections of the public who can barely read and write. Yet this situation does not apply everywhere” (Gigerenzer 2015). Where to begin? I will restrict myself to noting that it is rarely a good idea to insult the people of whole nations, or to contend that large sections of their public “can barely read and write.” Insults of that kind do not have the most honorable predecessors in Europe. Aside from its savagery, the comment is especially bizarre because so many nudges are in writing, and so depend on the ability to read and write.

This essay draws on, revises, and updates an earlier one, Misconceptions About Nudges, 2 J. Behav. Econ for Policy 61 (2018).

Author :

Cass R. SUNSTEIN est Robert Walmsley University Professor, Harvard University.