Welcome to the second in a series of articles explaining the biases, nudges and heuristics influencing behaviour and changing the way we think as marketers and this week's focus is Commitment - public pledge bias.

So, what is Behavioural Economics?

The field of behavioural economics blends elements of psychology and economics, and provides some valuable insights into why individuals are not behaving or making decisions in their own best interests.

Every week, we’ll be getting into the nitty gritty of a bias, nudge or heuristic, giving you a bit of insight into what it is and how it’s been applied. This week, it’s Commitment – public pledge bias.

What is Commitment - public pledge bias?

The more public pledge is the more likely we are to keep it.

So, what does that mean?

We tend to be consistent with what we have previously done or said we will do, particularly if this is in public. The more people that know about our pledge, the less willing we are to change it. Inconsistency is not seen as an admirable trait and we don’t want to disappoint those around us by going back on our promise. So, if we commit to something publicly, we are more likely to stick with it.

“Commitments are often used as a tool to counteract people’s lack of willpower and to achieve behaviour change… the greater the cost of breaking a commitment, the more effective it is”

(Dolan et al., 2010)

Classic examples of Commitment bias…

John Lewis are a cut above the rest when it comes to commitment. Since 1925, they’ve been leading the way with their price promise pledge, ‘Never Knowingly Undersold’. In their own words, it’s “the heart of everything we do and part of the service you’ve come to expect of us”.

They’re committed to pricing their products fairly and if it’s available at a lower price somewhere else on the market, they’ll happily match the price. The reasonable, thoughtful and customer-centric approach means people are bound to build brand trust.

Behavioural Economics, John Lewis
2012 TV ad still for John Lewis' Never Knowingly Undersold campaign

Who’s using it now?

More and more brands are branching out into the world of commitment, giving their brand a human, compassionate, approachable edge.

In 2004, Dove showed their commitment to redefining beauty with their campaign, “Real Beauty”, which featured real, everyday women. The campaign came off the back of their “Real Beauty Pledge”, which is a promise aimed at women all over the world:

  1. We always feature real women, never models
  2. We portray women as they are in real life
  3. We help girls build body confidence and self-esteem
Behavioural Economics, Dove Real Beauty campaign
Dove 'Real Beauty' campaign, 2004

The campaign photographs were shot by renowned photographer and Creative Director, Mario Testino. Featuring 32 real women from over 15 countries, all aged 11 to 71, the campaign perfectly reflected Dove’s pledge. And since then, the definition of beauty has taken on multiple meanings, fully embracing real women.

With the environmental-warrior coming out in a lot of us off the back of plastic pollution, Iceland have shown their commitment to the cause. They pledge to remove the plastic packaging from its own label products by 2023 simply “because we care”, making a bold commitment to something that pulls at a lot of consumer’s heart strings.

Stick to your commitments…

Although most brands are using public pledges successfully, some have also missed the mark. Countless companies guarantee that they’ll deliver products within a certain timeframe, which for customers, when it works, it works wonders.

Toys R Us however infamously failed to deliver packages on time during the festive season. As a result, they not only angered parents and disappointed children, but they damaged their reputation in the process. So, lesson learnt. If you’re going to commit to something, stick to it.


Behavioural Economics has been around since the 60s and their value and relevance in explaining why we make the “mistakes” or choices we make as consumers is compelling.

As an agency, influencing behaviours is core to what we do and applying Behavioural Economics to marketing communications is a natural progression. Find out how we used Commitment bias for the Buildbase Club Renovation Programme by reading our case study.

If you are interested in understanding more about how we do this get in touch now.

Be sure to check out next week’s post when we’ll delve into another bias or heuristic. And read last week’s Authority bias post here.

By Melissa McPhillips