The nudge hype

First, let’s explain nudging. Nudging is:

Any aspect of the choice architecture (environment) that can be altered to influence behaviour in a predictable way, without forbidding options or changing economic incentive.

— Thaler & Sunstein (2008)

Nudging assumes consumers are rationally bounded– that is, while consumers can make conscious decisions, the reality is that people are busy, time-poor, tired, emotional or lazy. Therefore, consumers often revert to intuitive mental processes, such as heuristics and habits (see the Institute’s report #71: Fundamental Consumer Insight). Given the role of habits in our everyday lives, it seems reasonable that nudging may be an effective behaviour change tool. If we change environments to inhibit or stop less desirable behaviours (not buying our product), and prompt for more desirable behaviours (buying our product), behaviour change could be achieved, and quite easily.

The ‘easy sell’ of nudging is evident by its association with best-selling books and Nobel prizes. Even Government departments have been caught up in the nudging hype. The UK Governments Behavioural Insights Team (aka the ‘Nudge Unit’) and the White House’s Social and Behavioural Sciences Team (aka the ‘President’s Nudge Unit’) are examples of government departments formed to implement behavioural economics and nudging in public policy. Advertisers and marketers have also looked to nudging as a new and innovative way to sell products and services (NB: price promotions are not nudges as they change economic incentive, by appealing to more cognitive decision-making). While research is scant, more alarming is the recent falsification and retraction of many nudging-related studies. Being the sceptics that we are, and the advocates of evidence-based marketing, we look past the nudging hype and search for reliable evidence for their efficacy.

What are nudges, exactly?

There have been different attempts to classify different ‘types’ of nudges. One of the more well-known classifications comes from Blumenthal-Barby & Burroughs (2012), who identify six types of nudges:

• priming (i.e. subconscious cues);
• salience (i.e. examples and explanations to increase attention);
• defaults (i.e. a pre-set option), incentives (i.e. rewards or punishments);
• commitments and ego (i.e. public commitment or promise); and
• norms and messenger (i.e. comparison to others).

Empirical investigation of these types of nudges is lacking, making the necessity, selection and implementation of a nudge very much a guessing game.

What is the evidence for nudging?

We employed the highest level of evidence, a systematic literature review, to evaluate studies that tested the effectiveness of nudging strategies applied to food and beverage choices (Wilson, 2016). A systematic literature review adheres to a structured protocol for identifying, synthesising and analysing studies relevant to a proposed topic. This method is the gold standard, considered to be the highest level of evidence in health research due to the rigour and strict criteria that must be adhered to in order to qualify.

To identify studies relevant to food and beverage choices, we conducted a comprehensive search of journal databases using the keywords: nudge, choice architecture or behavioural economics and food, diet or drink.13 papers comprising 26 studies were identified, conducted across cafeterias, self-service buffets and cafes, as well as laboratories. Despite the different types of nudging strategies that have been described, in these studies only two types were tested for effectiveness: ‘priming’ and ‘salience’ nudges. Given the increasing popularity of the nudging concept as evident in advertising, the media and government announcements, the number of academic publications which referred to their interventions as nudging interventions was surprisingly low.

The ‘priming’ nudges aimed to influence the visibility, availability and/or accessibility of food and beverage choices by changing the placement of food and/or beverages on the shelf, on menus or at a self-serve table. ‘Priming’ nudges had mixed efficacy. Out of 12 studies, seven found that ‘priming’ nudges were effective for influencing the selection of food and beverage choices. However, for the other five studies, they either did not influence behaviour, or increased selection of the non-nudged option. There was some evidence to support that more visible, accessible and/or available products were selected more often, which relates to the decreased amount of time and effort required to mentally and physically access an option. Yet, the lack of a consistent or predictable effect (whether there was an effect at all) across all studies is important to note.

‘Salience’ nudges were changes to the labelling on food and beverage items (i.e. calorie content, traffic light or descriptive labels) and other verbal cues aimed at raising consumer awareness of a recommended choice. Of the 11 ‘salience’ nudges tested, again the results were mixed. Five did influence behaviour, increasing the selection of the nudged options, while the remaining majority of studies had no effect or increased the selection of the non-nudged option. The most effective ‘salience’ nudges were those that provided information about taste or health attributes of food and beverage items through presenting a simple message (i.e. short claims and traffic light labels).

The trend towards products being chosen more when they were more, accessible, available, or had a visual element that might capture consumer attention, is consistent with the Institute’s findings. Brands that are more prominent in purchase and/or consumption situations (i.e. more physically available) are more likely to be bought.

Priming nudges were more effective than salience nudges. However, a combination of the two is the most effective approach. Three studies tested both ‘salience’ and ‘priming’ nudges combined, where traffic light labels were introduced, and the visibility, accessibility and availability were altered. These studies were limited to a cafeteria setting. A combination of these nudges resulted in a more consistent effect, with more purchases for the nudged options and reduced purchases of the non-nudged options. The consistency in their effect on the intended behaviour suggests that a combination of nudges (i.e. making an option of mentally and physically available) may have a more reliable and predictable influence on behaviour. A lack of predictability is important given that the definition of nudging suggests that a nudge should influence behaviour in a predictable way.

Interestingly, none of the studies had tested nudging in retail settings such as convenience stores, supermarkets, hypermarkets or online stores. However, consumers relate accessibility to physical accessibility, which may be the visibility, proximity to or ‘ease of reach’ of an option. Thus, making options easier to physically access increases consumer preference for these options, regardless of the retail format.

The key finding from our review is that the evidence for different nudge strategies is scant, and for those nudges that were tested across a variety of settings, there is a lack of consistent and conclusive findings for individual nudges and their influence on food and beverage choices. It could be that multiple nudges are required, that nudges have not been implemented well, or that they have short-lived effects (Wilson, 2015). It is also possible that their effect on behaviour is too subtle in contemporary environments that are cluttered, overwhelming, and filled with multiple cues all aggressively competing for consumers’ scant and distracted attention. Overall, nudges can facilitate some behaviour change, but in an unpredictable way, which suggests that nudges are not a reliable marketing tool. However, the inconsistent influence may also demonstrate the probabilistic nature of consumers which may be due to other factors, such as pricing and personal preferences (i.e. entrenched loyalties) and habituated behaviour.

The life of a nudge

Prior studies were conducted over shorter periods of time (a couple of weeks at most). Therefore, their effectiveness in the longer-term has had minimal investigation. To test the effectiveness of nudges over a longer period, we employed another high-quality method: a randomised control trial. Participants were allocated to one of two groups. One group received a letter each month (control group), whereas the other group received between four and six nudges every month for six months (intervention group). Several nudges were used to maximise their effect across multiple points of food and beverage-related decision-making (i.e. around the home, in the supermarket, when out and about). Examples include a mug with images of healthy breakfast options, a shopping bag with an image of fruit and vegetables, and a shopping list which had a large green section for fruit and vegetables and a small red section for snacks. The ‘self-nudging’ approach gave the consumer the control of implementing the various nudges in their daily lives. However, this intervention did not have a consistent influence on behaviour. While those who used more of the items were more likely to engage with the nudged behaviour, for the majority of people, the nudges were ineffective. An important finding was the diversity in what nudges people used and responded to – what was found to work for some people did not appear to work for others. Overall, even when combined and evident across many environments, nudges have a very subtle, if any, influence on behaviour.

Nudge – Is it just a sexy name?

Interestingly, we found that the strategies claimed as ‘nudging’, are in fact, similar to other behaviour change tools used in different disciplines. We note that nudging has been used to describe point-of-sale promotions (but not price discounts) that have been used for many years in marketing. Examples include retailers increasing the prominence of brands by placing items at eye level, allocating more shelf space, or placement in more visible shelves, marketers using claims on packaging to highlight a product’s attributes, and public health implementing the traffic light and calorie labels to try and encourage healthier choices. Given these similarities, the results are not so surprising. We know as marketers that point-of-sale promotions alone are not sufficient for growing a brand. They can have a subtle influence on behaviour (but importantly only of those, relatively few people, who are reached), but a brand also requires ongoing mental and physical availability across many consumer environments.

While nudging as a concept is increasingly popular in industry and public policy, we conclude that nudging is not a new concept, but rather just a new, sexier name given to existing behaviour change (and marketing) strategies. Perhaps the appeal of nudging and the reason for its hype (despite a lack of conclusive evidence for its efficacy) is due to the catchy name and simple, non-discipline specific terminology which makes it easy for everyone to understand – it has mass appeal!

Key insights

• There is inconclusive evidence for the efficacy of ‘priming’ (i.e. prominent place of shelf) and ‘salience’ (i.e. changes to packaging) nudges. Indeed, some nudges increased the selection of competitive, less desirable options. So proceed with caution.
• Using multiple nudges simultaneously may be more effective, but further testing is required.
• Nudging appears to have a short-lived effect. Nudges may require continuous delivery to gently nudge individuals behaviour over time, and to maximise the likelihood of reaching new, previously non-nudged individuals.
• Nudging is not dissimilar from other marketing tools (apart from price promotions) which target similar psychological constructs: physical and mental availability.
• The effectiveness of nudging supports much of what we already know about consumer behaviour and the effect of marketing efforts. Advertising is not a persuasive tool, rather it aims to have continuous, wide-reach to subtly nudge people’s buying propensities over time, while in-store activities can have short-lived effects due to their limited reach over time.

Summary

While there are many nudging strategies available, our research suggests that the evidence for nudging is scant, and that nudging alone may not be an effective strategy. By all means experiment, but don’t put all your faith in nudging effects. Instead, we urge you to stick to what you already know: develop products and services that meet consumer needs, ensure broad reach to help with customer acquisition, focus on advertising that increases the mental availability of your brand, and ensure that your brand has good physical availability across various retail platforms.