For the second interview of the initiative “Meet the Experts” we talked with Paulius Yamin, a behavioural scientist with a background in cultural and anthropological studies who researches the possibility of achieving behavioural change by intervening on social norms. He is currently the Managing Director of the Center for Social Norms and Behavioural Dynamics at the University of Pennsylvania and a Visiting Fellow at the Department for Psychological and Behavioural Science at the London School of Economics and Political Science. In the past, he has been a Co-founder and Managing Partner at the Behavioural Lab (Lithuania), an External consultant to the International Labour Organization (UN Agency), and the Manager of the National Behavioural Change Strategy for Public Servants at the Colombian Government. We had a chat with him about his research and his experience in the field.
How do you define social norms and how are they related to behavioural change?
Social norms can be defined in different ways. The definition I like the most and I use in my work is “the perceptions people have of what is typical and acceptable in society, especially regarding behaviours”. A very important element of social norms is the expectation we have about how others will act and react to our own behaviour. Social norms are basically about what is acceptable or desirable to do (or not to do) in certain situations for certain groups. They are related to behavioural change since it seems that they are important for determining our conduct in the real world. They are not the only factor involved, but they are largely relevant. So, consciously influencing existing social norms or creating new ones affects people’s behavior.
What are the main anthropological and cultural factors that affect social norms?
It is surely important for the survival of species to have some social proof of what is typical and acceptable. Social norms helped in the reproduction of cultures via shared rituals and meanings, but I think that today they are important especially because they allow us to live in both small and complex societies, as they are useful to communicate what the expected behaviour should be. There’s clearly debate here about the role of power, control and discipline, but people from developing countries, like myself, know that laws are never enough because not everybody will comply with them if they are not supported by any social regulation.
Why does the approach based on social norms seem to be one of the most effective among those to address behavioural change (from nudging to enforcement)?
I think this happens because as a species, humans care a lot about what others do and think and we are always paying attention to this either consciously or not. Sometimes it’s just because we do not have enough information about whether doing something is dangerous, therefore we can only rely on what others say to guide our decisions. Sometimes there are more complex forces involved, like power, but in any case, we always seem to care a lot about social norms.
Which are the main fields that can benefit from this approach based on social norms?
The way I see it is that in almost any field or situation in which compliance from the people (citizens, employees, clients and so on) is needed, behavioural interventions and social norms are very useful. Some methods that have been used to try to make people do certain things are not optimal. Indeed, humans are not computers that receive an instruction and automatically comply with it. A lot of times we do not respond well to direct orders without explanations. So there is a different level we should work on and this can be applied to many fields. We can have a proof of the broadness that this approach can take by looking at the list of topics that institutions are working on around behavioural science and social norms more specifically: it is a list with more than a hundred different topics, from recycling to corruption, retirement, savings, domestic violence, and many others. However, the common objective is to create some adherence to specific rules.
Which are the main techniques adopted, practically speaking, to influence social norms?

First, we need to have a clear understanding of the goal we want to achieve and to differentiate between beliefs, attitudes and actual behaviours. Going a step further I would say that targeting actual behaviours is extremely important because sometimes people can change their beliefs but not their actions and behaviour is what we mostly care about. Second, we have to understand and measure the norms and the groups we want to work on. If we do not know how many people in a group believe something or how many specific subgroups there are in a group, we could be doing something that is not effective. Many initiatives in behavioural sciences often take this approach, but I think that before starting with interventions it is necessary to understand social norms and the networks that are behind them. Another important point is to work with people. Of course, it is possible to apply nudges without people’s knowledge or understanding but, at least in my experience, it is very important to involve the stakeholders. In terms of specific techniques, in the last couple of years I published a systematic review of the main tools used until now, from TV campaigns, workshops and fliers to sending people to speak with their neighbours. In general, we have to consider three big elements to influence people’s behaviour: the physical side, the psychological side and the social side. Moreover, there is a distinction between campaigns that just give group summary information and those that communicate what is typical and acceptable through direct interactions or by showing what other people do.
Social norms are very group and situation specific, so interventions should be specific as well. How can this diversification be addressed when trying to design interventions for universal issues, such as environmental sustainability or healthy habits?
There is a lot of debate around this. What I believe in general is that the perceptions and expectations on which social norms are based are group and population specific, but it is difficult to measure how big the group is. It could be a building, a neighborhood, a city or a whole country.
In theory, if you wanted to change a social norm around the whole world, you could do a representative survey for the whole world and then apply one or more interventions which would affect the majority, but the effect would probably be unequally distributed. The same happens at the country level, we have not found a way to change the hundred per cent of the population.
Can you provide an example from your experience of successful intervention?
The Centre [for Social Norms and Behavioural Dynamics] right now is working on a big project in India with the Gates Foundation trying to study and change norms around sanitation and open-air defecation. We are currently starting the evaluation of a large randomized control trial, related to a campaign for the introduction of descriptive norms around toilet use in few areas of India. We do not have the results yet, to officially say that the intervention is successful, but I am quite confident that we will get good results.
Another example from my own research is the work that the former mayor of Bogotá has done to achieve policy goals such as reducing domestic violence and homicide rate. Among other things, they sent actors in the streets of a specific city, created a telephone line for people that were jealous, distributed red whistles for people to call for help if they saw domestic violence happening. At the end of the two-year intervention, they had effectively reduced the rate of domestic violence in that city by 40%. It’s a matter of doing it with the people, being creative and measuring in the right way.
Is the concept of social equality a social norm? If so, can intervention on this social norm be effective to tackle social inequality?
It surely can be, as there are beliefs about how typical and desirable inequality or equality is in a society. At the Centre we study the perceptions of people towards inequality in the US and how they affect their behaviours. We must also take into account if people even perceive inequality or not and what is inequality to them. If we make inequality less acceptable for people, we can encourage them to take specific actions to tackle it.
The Covid pandemic distorted the world we used to know. What are the effects of the pandemic on social norms? Is it possible that social distancing and lockdowns altered individuals’ tendency to conformism?
It’s difficult to say it now without first analyzing the data. However, I believe there have been changes in social norms and behaviours, for example in the desirability of remote work or in the compliance with the safety measures. We did a study at the Centre on a representative sample of nine countries, trying to explore the social norms behind the safety measures and we found out that social norms are relevant in this case only if people have trust or interest in science. We still have to understand which groups exactly were affected and the scale of this impact.
Which suggestions would you give to students interested in this field?
I chose to study and work in this field because of a political motivation, wanting to understand how we can make the world better and how we can improve policy outcomes in complex contexts. I gradually realized that most policy objectives have an important social, cultural and behavioural dimension. My suggestions to students would be to keep exploring, since it is always possible to find a behavioural dimension. One thing I really like about social norms and that I think it is really powerful is this idea of mutual regulation: it is not about an authority deciding and taking action, but it is about social strength, power and responsibility. Behavioural sciences have the potential to change the world, and we must use it. It is depressing for me to see studies and experiments that are good in theory but are not applicable in practice. We cannot rely only on studies conducted in universities in the US and Europe, but we have to collaborate and start to take seriously also the ideas and the experiences coming from all the other places.