Social Proof

Robert Cialidi first wrote about the power of 'Social Proof' back in 1984.

Today you might know that term as the bandwagon effect, conventional wisdom or crowd psychology.

Cialdi often refers to it as the "click whirr" response, like the press of a button.

While the social proof principle in the wrong hands can have negative consequences, it can also be used for good.

To prove his theory could be used to promote environmentally friendly behaviour, Cialdini set up an experiment trying to convince hotel guests to reuse their towels.

He split the guests into two groups, setting up a different sign in each room.

Group A's sign read, "Help save the environment by reusing your towels."

Group B's sign (using the principle of Social Proof) read, "Join your fellow guests in helping to save the environment."

Amazingly, guests in group B reused their towels 44.1% of the time, whereas guests in group A reused their towels only 35.1% of the time - a statistically significant result!


"The Blue Planet II Effect" is probably one of the most well-known cases of Social Proof being used for positive environmental change in modern times.

In the last episode viewers were shown images of a turtle tangled in plastic netting, and mother birds feeding their baby chicks plastic.

David Attenborough's Blue Planet II ended with this message,

"Never before have we had such awareness of what we are doing to the planet, and never before have we had the power to do something about that."

A study conducted shortly after the series aired found that 88% of people who watched Blue Planet II had since changed their behaviour as a result.

Unfortunately, as explained on page 1, many other studies have shown there to be an attitude-behaviour gap even for those who described  themselves as 'Green'.

Why am I telling you all this?

Because we all need reminders to make the right decision.

Because the choices we make have a huge impact on the environment.

And because using Social Proof you can trigger a response in others, urging them to follow through on their green intentions.

Reusable products can certainly help get people into the reusable mindset, but unless the message is EXPLICIT it is often lost.

We need reusable and sustainable products that SHOUT, "I am sustainable. Act sustainably!"

Then the message changes from "buy reusable products because it's the thing to do" to "buy eco-friendly products and services because we CARE about the environment".

'Click Whirr' 

This can have a cascading effect on buying behaviour.

People might decide to change their home energy to something more sustainable.

They may begin to opt for more sustainable food choices.

They may even begin cycling to work.


Now what if there was a coffee cup out there that created a 'positive' environmental impact directly after purchase, while generating Social Proof from the moment it was unboxed?