top of page

Does Nudge Need to Budge?

Nudge. If there’s one keyword to summarise a lot of behavioural science based interventions it would be this one. Whether we like or not. Issue is, lots of nudges have worked in one context, but failed to replicate in another. Meaning that nudging isn’t as generalizable as many had hoped. The solution? Budge!


To make sure we are all on the same page, a nudge is defined as “changes the presentation of choices (choice architecture) in a way that makes people more likely to pick the option that benefits them.” This is often quite subtle, and can be achieved through a variety of means. The nudging strategy which holds the highest success rate is that of using defaults, changing the choice from opting-in to opting-out, a strategy very successful with organ donations. Keep in mind that the only thing a nudge alters is the direct choice architecture (presentation of options). It does NOT change the way people’s beliefs change. Which is exactly where budge comes in. A budge is defined quite differently: “a generalizable intervention that starts from the question: how will the intervention affect the underlying psychology of the population?” Designing a budge has the goal of identifying the psychological mechanism that drives a behaviour, focusing on the psychology of the target population before attempting to change that behaviour. In short, budging goes much deeper.


The concept of budging was proposed by Hauser, Gino and Norton (2018), and it goes for beyond proposing a new concept. Rather than applying frameworks such as EAST or MINDSPACE for nudging, they introduce the BBC model (not to be confused with, nor affiliated with the British Broadcasting Corporation). The Beliefs–Barriers–Context model (BBC) comprises three components: understanding the Beliefs of the population, The Barriers that might present itself to execute the desired behaviour, and the Context in which that behaviour is taking place, as a way of changing behaviour. Through a budge. A great example of nudges failing, where budges would help, is the towel re-use example. The initial nudging study by (Goldstein, et al. 2008) focuses on making US hotel guests re-use their towels, as a way of reducing laundry usage and reducing the hotel’s energy consumption and increasing its sustainability, by providing the guests with the fake social norm that 75% of hotel guests did in fact re-use their towels. The study was massive success, and towel re-usage increased significantly. Social norms are a great way to nudge! Until this finding failed massively in a German replication, because it did not replicate at all (Bohner & Schlüter 2014) . So, are social norms in, or are they are out? Quick side comment: both EAST and MINDSPACE have an “S” in them, which does refer to social norms, or the social context in general. It would be “quite” embarrassing if it turned out social norms didn’t have an effect whatsoever… Getting back to budging, what was the issue here? The issue is the differences context, specifically the starting point of the intervention: within Germany towel re-use rates were already over 70%, whereas within the US, towel re-usage dangled around 30%. In the latter there was lots to gain. In the former, not so much. As always within behavioural science: context matters!


So how does one budge? Insert BBC (again, not the tv station, although that would be hilarious). Looking at Beliefs, the authors argue for gaining a deep(er) understanding of the existing beliefs in the target population. Questions to ask then become: What do people currently believe about the behaviour targeted for change? And as a follow up question: Are those beliefs accurate or inaccurate? Lastly: Would changing those beliefs meaningfully affect the subsequent behaviour of interest?

Then moving onto Barriers. Questions to now ask are: Are there are obvious, or sometimes more subtle, barriers in the way of a desired behaviour change? Removing barriers might be the first step to initiate behaviour change. Barriers can take different forms. One well-known example quoted by the authors is that of the context of healthy eating: unhealthy foods are often placed in highly visible and convenient locations in cafeterias, whereas healthy foods are not, and require the intention and motivation to search for them. An example which is more on the nose is the following: you can discourage able people from taking elevators and escalators and nudge them to take the stairs instead. But nudging, or budging, someone in a wheelchair to take the stairs is just cruel. And ridiculous. There is a clear barrier there. Lastly, let’s look at Context, understanding the physical and social setting in which a behaviour takes place. Questions to ask can be as simple as: When? With whom? Where? And all it’s negatives, such as when not? The appeal of the budge is simple: you’d know why an intervention (budge) worked, rather than see whether it did work, or not. This, choosing which nudge to implement largely being a matter of the existing evidence that a nudge worked in some other context, has been one of the main critiques of nudge. Amongst others.


For those with a specialization in behavioural change, or someone who’s really neck deep into behavioural science, several aspects of this model hardly seem new. It has to be mentioned, and as such I will mention it, that the BBC model, fits in quite well with the COM-B model (Capability, Opportunity, Motivation, Behaviour), where both Capability and Opportunity are investigating potential barriers, both physical, psychological and contextual barriers, whereas Motivation looks deeper into previously held beliefs and the psychological factors underlying behavioural change. These models share quite a lot of overlap. Thought I’d mention it.


References Bohner G, Schlüter L.E. (2014) A room with a viewpoint revisited: descriptive norms and hotel guests’ towel reuse behavior. PLoS ONE 9(8):e104086–e104087. Goldstein N.J., Cialdini R.B., Griskevicius V. (2008) A room with a viewpoint: using social norms to motivate environmental conservation in hotels. Journal of Consumer Research. 35(3):472–482. Hauser, O. P., Gino, F., & Norton, M. I. (2018). Budging beliefs, nudging behaviour. Mind & Society, 17(1-2), 15-26. Michie, S., Atkins, L., & West, R. (2014). The behaviour change wheel. A guide to designing interventions. 1st ed. Great Britain: Silverback Publishing, 1003-1010.

1 則留言

Wilfred Waters
Wilfred Waters

Thanks Merle!


Behavioural Science

Personal Finance



bottom of page