Understanding why - the importance of behaviour science in driving positive change

Date : 22 July 2020

Hannah Skeggs

Nutrition & Scientific Affairs Manager

In this article Nutritionist Hannah Skeggs explores how understanding consumer behaviour could be the key to empowering positive change. She discusses how science can be applied in real life settings to shift consumers towards healthier and more sustainable diets


As humans, we don’t always make rational decisions. Food is especially emotive, as while we need it to survive, we also see it as a source of pleasure; we use it to mark celebrations like birthdays and Christmas  and we  use food to reward and sometimes console ourselves and others. 
This means our eating habits go beyond just functional fuel and are often complex, personal, and hard to understand.

Food is not rational. Food is culture, habit, craving and identity.
Jonathan Safran Foer, Author

It’s because these decisions are multifaceted that education alone is not usually sufficient to change people’s behaviour1. Generally, we know what we should eat, the risks associated with smoking and why we should exercise regularly, but we’re all guilty of not following that guidance all the time. 

To get under the skin of how we can influence consumer behaviour, we need to understand people and why they really do what they do: what motivates this person, how do they feel and how does that influence their decisions?

All of these can be explored through the lens of behavioural science, which is increasingly used by government, academia, NGOs and leading businesses. When we consider ‘cognitive biases,’ or how our brains prefer to work, we can predict which interventions may be most impactful when changing habits.

Behavioural and social science research is also proven in many cases to reduce conditions such as obesity, or to provide non-drug interventions for managing chronic diseases, by promoting healthy habits2. Used effectively, it offers huge potential to improve the health of the population. 

Behaviour science in practice

Small nudges can have great impact. For example – did you know that experimental psychologist, Charles Spence found that changing the type or colour of cutlery used to eat a yogurt could significantly impact the perceived taste and texture?3 But let’s step away from food for a moment to understand why decisions aren’t always rational.

An example of one of the UK government’s most successful behaviour change interventions in recent years has been the introduction of the carrier bag charge, which is estimated to have reduced use by over 300 million bags in its first year. 

That works out as 19 bags used per person in England in 2016, compared to 140 bags the year before the 5p charge in 2015 – an impressive 86% reduction4.

What’s really interesting here is the mechanism for inspiring change. Mathematically and logically there isn’t much difference in offering customers a 5 pence discount for bringing their own bags (which a few stores had previously implemented) or charging 5 pence for each bag - but in practice it makes a big difference.

Imagine you are at the checkout and someone offers you a 5p discount off your £40 grocery shop. The discount feels minimal. But when the cashier wants to charge you 5p on top of your £40 shop suddenly it feels like a cost. This is because behaviourally losses feel greater than gains. Loss- aversion theory suggests that the pain of losing is psychologically about twice as powerful as the pleasure of gaining5. It’s the same reason why charging for a coffee cup is more successful than giving you a discount when bringing your own.

The challenge with using behaviour science in research is that there are hundreds of cognitive biases - just like loss aversion - to consider. 

Behaviour shortcuts

To make the science more accessible, we partnered with behaviour change experts at Walnut Unlimited. Walnut has developed a simple framework that we applied throughout our research. It brings together five key shortcuts that our brains make when making decisions. 

The five shortcuts are based on principles from behavioural economics, psychology and social sciences. 


Think about



How are the options presented?


Framing losses

How choices are presented, whether it be as a loss or as a potential gain affects the choices we make.

Example: Actively marketing only diet varieties of soft drinks has been shown to make them more appealing to consumers than the regular varieties.

Framing the healthier choice as a positive, rather than missing out, helps shift purchasing.


Are there any social influences present?


Social Proof

People use the behaviour and attitudes of others to influence their own.

Example: Products with higher online ratings are more appealing than those with a low weighting.


People give weight to customer reviews and testimonials. They give even more weight to the review of a friend or family member.


What are the emotions evoked?


Loss aversion

The pain of losing looms much longer than the joy of a gain of equivalent value.

Example: A 5p carrier bag charge is significantly more successful for reducing plastic than a 5p discount for bringing your own bag.


We try harder to avoid losses than to receive gains of equal value.


How easy it is to understand and to action?


Chunking and sequencing

Information grouped into familiar, manageable units is more easily processed and remembered. We are more likely to take action when complex activities are broken down into smaller tasks.

Example: Telling people to reduce meat can seem hard.

Inspiring them to give up meat each Monday and providing recipes to do so feels more manageable.

We find it easier to take small, defined, sequenced tasks.


Is there anything that motivates to do it again?


Feedback Loops

We are motivated when we see how our actions modify subsequent results.

Example: A product claim ‘20p from your purchase will benefit a local charity’ can encourage purchase.

We are motivated when we see how our actions create subsequent results.

Using the model to shift consumers towards healthier and more sustainable diets

Over recent years, we’ve seen an explosion of high-profile literature looking at how we can achieve a healthy and sustainable diet, some examples include Eat Lancet6, WWF Livewell7 and the BDA’s One Blue Dot8. Despite this topic being broad and complex, all these studies acknowledge an urgency to act, as no matter what a healthy and sustainable diet may look like – we are a long way from achieving it.

Unfortunately, we know that educating people, or simply telling them what to do, will not be sufficient to create the sustained behaviour change required. So, at IGD, we’re using behaviour science to identify how we can make this transition easier for people and help to deliver positive change for not only consumers but also the planet.

Each time we eat and drink, we vote for the world we want to live in
Emmanuel Faber, CEO Danone

In 2019, we used both qualitative and quantitative research to explore the concept of healthy and sustainable diets with over 1,000 nationally representative shoppers. By partnering with Walnut Unlimited, we’ve gained a deeper understanding of the conscious and subconscious drivers behind consumer decisions. We found that 66% of consumers of people are thinking about or already changing their diets, and they want help to do it. And from this, we identified the most effective levers that food retailers, manufacturers, and foodservice can pull on to promote behaviour change.

Looking at the results from both the qualitative and the quantitative stages, we identified five key approaches to encouraging change, which I’ll be exploring through more detailed articles over the next few weeks.

A summary of these is:

Ease: Make the first steps easy. We are more likely to act when complex activities are broken down into easy tasks, e.g. Meat free Mondays is seen as an easy, achievable way to take a simple step

Signposting: Use signage to make the right choice easy and highlight the potential gains over perceived loss, for example, use labels to highlight healthy and sustainable options

Placement: Prime positioning encourages more browsing for those who do not typically eat this type of food and allow for comparison. For example, placing plant-based options side-by-side with meat products provides proximity and ease. Online suggestions can also play a key role for many who are looking to make changes to their diet.

Product: Ensure healthy and sustainable options are appealing and inspiring for example plant-based meat alternatives are an easy switch for those who eat little meat, offering convenient meals that they know.

Influence: Inspiring ideas and influencers can play a key role, for example, recipe cards and online influencers can motivate and inspire change

How can we activate this in real life settings?

This year, we began a conversation with stakeholders from retail, manufacture, out of home, academia, and government to explore how we could apply these theoretical levers to real life situations and measure the impact. 

While COVID-19  has impacted timelines, we’ve heard from industry that healthy, sustainable and affordable diets are more important than ever, both in meeting consumer demand and in the efforts to build back better after the pandemic?

IGD has established a project group of key manufacturers and retailers to help test and share the most effective solutions to drive behaviour change. This will help us to take positive action, and shift consumers towards healthier and more sustainable diets both now, and in the future.

Get in touch to learn more: [email protected]

Balmford, A., Cole, L., Sandbrook, C., Fisher., B 2017. The environmental footprints of conservationists, economists and medics compared. Biological conservation. Volume 214, pages 260-269. Available here
2 Office of Behavioral Social Sciences Research. Information for the public.  Available: http://obssr.od.nih.gov/Content/Research/BSSR_Guide_To_Grants_at_NIH/ [Reference list]
3 Harrar, V & Spence, C., 2013. The taste of cutlery: how the taste of food is affected by the weight, size, shape, and colour of the cutlery used to eat it. Available: https://flavourjournal.biomedcentral.com/articles/10.1186/2044-7248-2-21
4 DEFRA, 2018. Plastic bag sales in 'big seven' supermarkets down 86% since 5p charge. Available: https://www.gov.uk/government/news/plastic-bag-sales-in-big-seven-supermarkets-down-86-since-5p-charge
5 Kahneman & Tversky, 1979. Prospect Theory: An Analysis of Decision under Risk. Econometrica, Vol. 47, No. 2 (Mar, 1979), pp. 263-291
6 The EAT-Lancet Commission. Can we feed a future population of 10 billion people a healthy diet within planetary boundaries? Available: https://eatforum.org/eat-lancet-commission/ [Accessed Feb 2020]
7 World Wildlife Fund, 2017. Eating for 2 degrees. New and updated Livewell Plates. Summary report, revised edition. Available: https://www.wwf.org.uk/what-we-do/livewell [Accessed Feb 2020]
8 British Dietetic Association, 2019. One Blue Dot. Available: https://www.bda.uk.com/resource/one-blue-dot.html [Accessed Feb 2020]