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The Timeless Power of Social Norms

by Karen Christensen

Interview with Kristen Duke, Professor of Marketing, Rotman School of Management

How do you define ‘social norms’?

Social norms are our understanding of what is expected of us and what is appropriate in particular situations. Some people describe them as informal ‘rules of behaviour’. We learn these over time as we encounter other people and observe how they behave and hence what is expected of us. For example, in different cultures there are different expectations around tipping behaviour. In some places you tip the server a certain percentage, while in others you might just tip a few cents. Another example is norms around how we interact with strangers in different places around the world — such as whether we look them in the eye and smile at them on the street.

Norms are enforced by our peers’ interactions with us. When we follow norms, we get social approval; we get to fit in, and we feel comfortable. When we violate norms, we may be penalized socially. As social animals, we have a strong desire to fit in and not to be left out of the group. That’s why norms so powerfully influence our behaviour. 

Why are social norms of interest to organizations?

Like all human behaviour, workplace behaviour is often dictated by social norms. For instance, workers might have expectations around punctuality and when they should be in the office, and there may be norms around who can speak up in meetings. When we think about trying to get people to behave in a particular way, we often think about which rules we should put in place, whether it be official structures or incentives. But in fact, social norms are implicit, subtle cues that people share with each other, and they can be even more powerful at shaping behaviour due to our deep-seated desire to fit in. Essentially, changing people’s perceptions of social norms is a pathway to changing their behaviour.

Efforts to shift social norms towards healthy behaviour often involve explicit messaging. Does this work?

Research shows that explicit messaging campaigns can be really powerful. For instance, there is evidence that they have reduced binge drinking on campuses as well as public littering, and they have also increased recycling and other pro-environmental behaviours. But these campaigns can also backfire. One study looked at what happens when you tell people how much energy they’re using in comparison to their neighbours. For example, you might receive a notice saying that you use 70 per cent more energy than the guy next door. That might make you feel bad, and you might change your behaviour appropriately. But of course, some people are doing better than average — for example, using less energy than 70 per cent of their neighbours, and when they learn that they’re exceeding this social norm, it can actually lead them to conserve less energy. This is one possible downside: a ‘boomerang effect’ can occur when you provide people with norm information.


As social animals, we have a very strong desire to fit in.Tweet this


There is also the general possibility that people recognize ads as ads. If I encounter an advertisement telling me why I should or shouldn’t do something because of a social norm, I might purposely ignore it because I view it as a blatant attempt at persuasion. Some people might be annoyed by the fact that someone is trying to tell them how to behave. So there are pluses and minuses to explicit messages.

What are some of the most effective incentives for changing social norms?

Typically, when people think about changing norms, they think about what we just discussed with explicit messaging. There has also been some interesting work showing that laws can inadvertently change perceptions of norms. For example, researchers tracked Americans’ perceptions of whether they think other Americans oppose or support same-sex marriage during the period of the U.S.  Supreme Court decision around it. When the law passed, perceptions shifted, because people assumed more of their fellow citizens approve of it as well. So people can learn norms from observing others, from explicit messaging campaigns, and from laws and regulations.

In your research you looked at how incentives ‘leak’ information about social norms. Please elaborate.

We noticed that there were more and more small incentives designed to encourage pro-environmental behaviours. Some coffee shops were offering discounts for people who brought their own mugs; some grocery stores were offering discounts for people who brought their own bags or bins. And on the other side, there were also surcharges being imposed at certain places. Some coffee shops charge you extra for a paper cup, and some grocery stores charge you for plastic bags. These incentives affect people’s behaviour for many reasons.

The obvious one is that people care about money, so if they perform a desired behaviour and they get a reward for it — like a discount — this is incentivizing, because people like to earn money. On the flipside, if they are penalized for not performing a behaviour, they may have to pay a charge, which is painful because people don’t like to part with their money.

We found that beyond those monetary considerations, the way the incentives are set up actually affects people’s understanding of the social norm. If I encounter an incentive that is set up as a surcharge, I will infer that the desired behaviour is more common among the customers who frequent that location — that it is a descriptive norm. I will also infer a stronger prescriptive or injunctive norm, which is that the behaviour is expected and appropriate. The way these incentives are structured subtly reveals information about what other people believe is the proper behaviour.

The way incentives are framed also conveys important information. Describe the difference between ‘advantaging policies’ and ‘disadvantaging policies’.

You can set up a policy in a way that you give an advantage to people who perform a desired behaviour. If you do nothing, then nothing happens to you; but if you do something desirable, you get some benefit. And you can also set up a policy to be disadvantaging — so if you fail to perform a desired behaviour, you are penalized or disadvantaged relative to the rest of the group. Interesting work by Ellen Evers and her colleagues showed that advantaging policies are seen as more acceptable by people if they are tied to voluntary behaviours, and disadvantaging polices are more acceptable if they’re tied to obligatory behaviours.

In our studies, we extend this work: we view surcharges and discounts as small incentives that share this structure of being disadvantaging or advantaging. We felt this idea of policy acceptance might translate into what people perceive when they encounter these incentives in daily life. So, advantaging polices might be seen as indicating that in general, people do not perform a behaviour at a high rate and disadvantaging policies might show the opposite. And that is indeed what we found. surcharges seemed to show people that the desired behaviour was quite common and socially expected, while discounts showed that it was less common and expected.


Changing people’s perceptions of social norms is a pathway to changing their behaviour.Tweet this


You also found that exposure to incentives influences people's behaviour not just initially, but down the road. Tell us about that.

Most people think of incentives as being effective solely for monetary reasons. There’s classic work on loss aversion showing that losses loom larger than gains. If I have to pay a $0.10 charge, it will affect me more strongly than if I receive $0.10 back as a gain. This work would suggest that surcharges will always be more powerful than discounts just because they are stronger monetarily. But we found that because these incentives are leaking information about social norms, they can affect people’s behaviour not just when they experience the incentives, but also later down the line. If I learn from the presence of a surcharge that there is an expectation in my community that people will perform a behaviour, then even in another situation where I don’t have any incentives, I will likely follow what I’ve learned and spontaneously carry out the previously incentivized behaviour.

As an illustration, we ran an experiment offering people a chance to purchase gum. Since it was during flu season, we incentivized participants to use hand sanitizer. In one condition, they could get a discount on the gum if they used hand sanitizer, and in the other, they had to pay a surcharge if they did not use it. After this purchase opportunity, participants completed various unrelated activities. On their way out of the lab, we watched whether people would spontaneously use the hand sanitizer that had been left at a table near the door. We found that the people who had earlier seen the surcharge (vs. discount) were more likely to spontaneously use the hand sanitizer — as if they had learned that this is how they are ‘supposed to behave’. 

For readers who want to put your findings into practice, what are the key takeaways?

The main takeaway is that we should think about incentives not just as affecting motivation in monetary terms, but also as vehicles for conveying information to people. When we consider instituting incentives in different environments to try to change behaviour, we should think not only about how people will react to the monetary input, but also, how this information might affect social norm inferences and behaviour down the line. As indicated, there can be ripple effects.  

Kristen Duke is an Assistant Professor of Marketing at the Rotman School of Management. She won the 2019 Robert Ferber Award for co-authoring the best dissertation-based article published in the Journal of Consumer Research, “Guilt Dynamics: Consequences of Temporally Separating Decisions and Actions”, co-authored with On Amir.

This article appeared in the Spring 2020 issue. Published by the University of Toronto’s Rotman School of Management, Rotman Management explores themes of interest to leaders, innovators and entrepreneurs.

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