If you say something publicly, you’re more likely to stick to it.

What is the commitment public pledge bias? 

The commitment – public pledge bias is the theory that if you tell people you’re going to do something publicly you feel like you have to stick to your guns. Take a new year’s resolution or race for life, once we’ve told people we’re doing it we have to follow through.

This also works with brands. You’re more likely to trust a brand that publicly states an opinion or value – be that commitment to the environment or better cleaning in-store. Once they’ve publicly pledged their stance, it’s hard to go back on it.

The evidence it works

Disney used the commitment bias on hotel guests, asking them to pledge to reuse their towels with a free ‘Friends of the Earth’ pin to wear. 

Guests were 25% more likely to reuse their towels once they’d pledged to – meaning an estimated annual saving of washing 147,000 towels. Leading to 700,000 gallons of water saved or $51,000.

Where it fits in our behavioural model – The ‘means’ METRIC

The three core principles of our Behavioural Model is that every behaviour has to have a motivation, trigger and the means.

The means are the resources to get what you want. This isn’t just money – choosing and buying also costs time and effort, thought and worry.

In theory, the means depend on what’s in short supply. So if we’re short of time, we’ll spend money. If we don’t want to take a risk, we’ll invest more thought. If everyone else is doing one thing, we’d rather join the queue and spend time, than feel like the odd one out.

But our judgement of these things is often flawed. For example, we can only judge numbers in comparison with other numbers and we’re inclined to not waste energy, so the easier something seems the more likely we are to choose it (like joining the queue). Which forms the basis of our Behavioural Model.

The means model is split into six different sections: Money, Effort, Time, Risk, Individuality, and Conscious thought. Which handily spells METRIC.

Commitment – public pledge falls into Individuality. People often choose brands who align to their individual views or values, and trust brands who are prepared to state those views publicly – because they’re more likely to stick to them. 

How we've used it with clients


The more public our stance or commitment, the more likely we are to carry it out consistently, which was the aim with our Covid-19 posters.

By making a commitment on the poster (and signing it) we’re providing certainty from the management about regular cleaning, reassuring customers that their health and wellbeing is important.


The commitment bias to help you stop drinking

Macmillan runs Stoptober each year – a public commitment to stop drinking usually made over social media. 

As well as public commitment in front of friends and family, adding fundraising gives people even more willpower. It’s hugely successful, raising vast amounts for the charity every year.


How we can help you

We’re an agency that makes your marketing more efficient with behavioural science. To find out how we can help you reach your goals, get in touch now.

By Ellen Jackson

Creative Copywriter