According to Thaler and Sunstein (2008, p. 6), a nudge 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. To count as a mere nudge, the intervention must be easy and cheap to avoid. Nudges are not mandates. Putting the fruit at eye level counts as a nudge. Banning junk food does not.
Perhaps the most frequently mentioned nudge is the setting of defaults, which are pre-set courses of action that take effect if nothing is specified by the decision-maker. (See also choice architecture.) This type of nudge, which works with a human tendency for inaction, appears to be particularly successful, as people may stick with a choice for many years (Gill, 2018).
On a cost-adjusted basis, the effectiveness of nudges is often greater than that of traditional approaches (Benartzi et al., 2017).
Questions about the theoretical and practical value of nudging have been explored (Kosters & Van der Heijden, 2015) with respect to their ability to produce lasting behavior change (Frey & Rogers, 2014), as well as their assumptions of irrationality and lack of agency (Gigerenzer, 2015). There may also be limits to nudging due to non-cognitive constraints and population differences, such as a lack of financial resources if nudges are designed to increase savings (Loibl et al., 2016). Limits in the application of nudges speak to the value of field experimentation in order to test behavioral interventions prior to their implementation.
As a complementary approach that addresses the shortcomings of nudges, Hertwig and Grüne-Yanoff (2017) propose the concept of boosts, a decision-making aid that fosters people’s competence to make informed choices.
Benartzi, S., Beshears, J., Milkman, K. L., Sunstein, C. R., Thaler, R. H., Shankar, M., Tucker-Ray, W., Congdon, W. J., & Galing, S. (2017). Should governments invest more in nudging?. Psychological Science, 28(8), 1041-1055.
Frey, E., & Rogers, T. (2014). Persistence: How treatment effects persist after interventions stop. Policy Insights from the Behavioral and Brain Sciences, 1(1), 172-179.
Gigerenzer, G. (2015). On the supposed evidence for libertarian paternalism. Review of Philosophy and Psychology, 6, 361-383.
Gill, D. (2018, February 20). When ‘nudging’ is forever—the case of Sweden. Chicago Booth Review. http://review.chicagobooth.edu/behavioral-science/2018/article/when-nudging-forever-case-sweden.
Hertwig, R., & Grüne-Yanoff, T. (2017). Nudging and boosting: Steering or empowering good decisions. Perspectives on Psychological Science, 12(6), 973-986.
Kosters, M., & Van der Heijden, J. (2015). From mechanism to virtue: Evaluating Nudge theory. Evaluation, 21(3), 276-291.
Loibl, C., Jones, L. E., Haisley, E., & Loewenstein, G. (2016). Testing strategies to increase saving and retention in individual development account programs. http://dx.doi.org/10.2139/ssrn.2735625.
Thaler, R. H., & Sunstein, C. (2008). Nudge: Improving decisions about health, wealth, and happiness. New Haven, CT: Yale University Press.