Principles of Persuasion: Social Proof

Principles of Persuasion: Social Proof

In his book ‘Influence: The Psychology of Persuasion’, Robert Cialdini describes 6 principles of persuasion:

  • Social Proof
  • Reciprocation
  • Liking
  • Commitment and Consistency
  • Authority
  • Scarcity  

These principles can be used to nudge citizens into behaviours that are beneficial to them. This blog post will discuss the Social Proof principle. 

An introduction to Social Proof

In March 2021, the BBC reported a sting from ‘Which?’ highlighting how UK businesses are buying 5-star Google reviews (BBC, 2021). Why are companies doing this?

They are doing it because they are aware of Social Proof.

Social Proof is the discovery that ‘humans assume the actions of others to reflect correct behaviour for a given situation’ (Lua, 2022). 

In short, humans follow what other people do. This is highlighted in Milgram’s famous street corner experiment in 1969. With two other psychologists, Bickman and Berkowitz, Milgram asked individuals on a street in New York to look up at the sky for sixty seconds whilst monitoring the behaviour of passersby. They found that if one person was gazing at the sky, around 40% of passersby would also look up, but none would stop. However, when fifteen people were staring at the sky, 80% of passersby would look up, and 40% would stop what they were doing and join the crowd (Milgram et al, 1969). 

People follow people. 

How has it been used?

David Halpern, the head of the UK Government’s Behavioural Insights Team (BIT), has used Social Proof to help local authorities in England influence the behaviour of its residents to pay their Council Tax promptly. 

The BIT team did this by changing the content of a late payment letter. They added the truthful line that ‘nine out of ten taxpayers pay on time’, increasing the payment rate by 4.5%. Then, the BIT team developed this message to ‘most people with a debt like yours had already paid’. This raised the payment rate by 16% because people are more likely to follow people similar to themselves (Halpern, 2015). 

How can it be used digitally?

Many organisations use the Social Proof principle in their online services. For instance, Amazon has a ‘What other items do customers buy after viewing this item?’ section. This feature highlights to the user the behaviours of other users who have viewed the same product. Additionally, Amazon has a reviews section. This feature offers users the opinions of other users who have previously purchased this product. 

By doing this, Amazon is nudging the behaviour of its users to follow the opinion and behaviour of other users who have previously purchased the product they are viewing. 

What to be careful of  

Social Proof can unintentionally encourage negative behaviour. This often happens when communications try to encourage positive action by highlighting negative social behaviour. For example, Cialdini, in partnership with Sagarin and Barrett, found that messaging in Arizona’s National Park that was trying to prevent visitors from stealing wood had an adverse effect. It highlighted how frequent stealing by people was a problem. This made wood stealing a social norm in readers’ minds, thus increasing the amount of wood stolen (Cialdini et al, 2006). 

This should be considered when designing content. For instance, highlighting how poor voter turnout is a growing problem will likely have the opposite effect that we hope. However, highlighting how most people who voted are happy they did (Blais et al, 2017) may provide us with the desired outcome. 

How can this help Welsh local authorities?

Welsh local authorities can utilise Social Proof to alleviate the stigma surrounding certain life events for citizens. Our research has shown how disabling the stigma associated with poverty can be. It contributes to citizens not accessing help for significant periods, sometimes for up to a year. 

Participants in the research mentioned that they felt more confident when they saw other people accessing services. By highlighting that other citizens in the area are accessing services like Council Tax Reduction or Free School Meals, it will help relieve that stigma and nudge citizens to ask for help at their earliest opportunity.  

How do you think Social Proof can help citizens? Let us know in the comments. 

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