OPINION25 August 2015

Bias in the spotlight: social norms – part 1


We have a common tendency to adopt the opinions and follow the behaviours of the majority to feel safer, to avoid conflict or simply to be more cognitively efficient in our decision-making.


We might do this for two different reasons:

  1. We use what others do as shortcut for decision-making. We don’t always have time to fully research choices and cannot be experts in everything. So sometimes it can be useful simply to copy others.
  2. We like to conform to peer pressure to fit in. Humans are amazingly social beings and we feel happier conforming rather than facing disapproval from the group.

Social scientists have identified two types of social norms:

  • Descriptive social norms – doing what everyone else is doing, e.g. buying the latest iPhone that everyone seems to be getting, saving energy in the home because you’ve heard all your neighbours are.
  • Injunctive social norms – what others believe or what others approve of and therefore what we know we should be doing e.g. tipping a waiter is a cultural norm, as is adhering to the speed limit on the highway.

In this article and the next, we look at two applications of descriptive and injunctive social norms – the first to nudge people to use sunscreen, the second to get them to pay their overdue taxes.

Everybody should wear sunscreen

As Baz Lurhmann, says in the song ‘Everybody’s free (to wear sunscreen)’, “If I could offer you only one tip for the future, sunscreen would be it. The long term benefits of sunscreen have been proven by scientists.”

And yet many of us don’t wear sunscreen – sometimes we forget, sometimes we are lazy and sometimes we simply don’t wear it because we feel that the risk of skin damage is far smaller than it actually is. And yet skin cancer is the most common form of cancer in the US and causes more than 10,000 deaths, while two thirds of Australians will be diagnosed with skin cancer before they are 70. Might leveraging social norms nudge people to behave differently and use more sun protection?

A team of researchers at the sun-drenched University of California, San Diego tested two different nudges both designed to encourage people to use more sun protection.

In the first nudge they showed people a UV photo of themselves which depicted underlying sun damage to their skin and made the skin damage more vivid.

In a second nudge given to some participants the researchers also showed messages leveraging social norms:

  •  an injunctive social norms message: using information about preventing photo-ageing to remind people that they should be protecting their skin from the sun;
  •  an inflated descriptive norms message: stating the number of their peers who were currently using regular sun protection e.g. ‘85% of college students say they use sunscreen on a regular basis’.

Showing people the UV photo of their skin and both the injunctive and descriptive social norms messages led around 60% of participants in the study to increase their sun protection behaviours.

While Baz Lurhmann’s lyrics are great, it seems that there are simpler ways to nudge people to wear sunscreen…

Crawford Hollingworth is founder of The Behavioural Architects