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Reconciling conflicting interests


Combining different disciplines, Leiden University researchers work together to formulate innovative solutions to societal problems. Below is an example from the field of societies around the world.

Overview research dossiers


Promoting cooperation between people, groups and states

If a society is to be secure, sustainable and resilient, conflicting interests must be reconciled. Researchers at Leiden University study the behaviour of individuals, groups and states in relation to this issue, and use their knowledge to promote equality within and between communities.

Reconciling differences

Wherever people live together, conflicts arise: between individuals, between groups and between countries. How can those conflicts be managed, so that societies are organised on the basis of equality? What is the best strategy for getting both sides to accommodate each other’s interests? To answer these questions, we need well-substantiated knowledge of human behaviour. Researchers at Leiden University contribute to this knowledge base by studying the behaviour of individuals and groups in complex arenas and with conflicting interests. They conduct this research from the perspective of different disciplines within the social sciences: political science, anthropology and psychology.

Human rights

Conflicting interests can be studied at various levels. Psychologists observe how individuals in a laboratory situation relate to the common good or to each other. They combine this with physiological research, to find a link between responses in the brain and the decisions that people make. Anthropologists go into the jungle and record what happens when the way of life of indigenous peoples is threatened by mining, or when their knowledge is stolen by Western companies. They use their expertise in such contexts as advising the Dutch government on buying sustainable timber, for example. Political scientists research the discussion about human rights between authoritarian states, international organisations and NGOs, seeking answers to such questions as how the various parties assert their rights. They talk to everyone concerned and discover that totalitarian regimes are becoming smarter in terms of gaining influence within international organisations. With this knowledge, scientists can pass on insights to diplomats and human rights activists to help them take the next tactical step.

Self-interest versus group interest

People are less willing to give up an interest when in a negotiation situation than when they can do it of their own free will, as Leiden University psychologist Eric van Dijk discovered. Knowledge of this kind can be used by policy makers, for instance, to motivate people to adopt certain desirable behaviour.

What decisions do individuals make when they have to weigh their immediate self-interest against a long-term collective interest? And what factors influence these decisions? Leiden psychologists design experiments to discover how people deal with social dilemmas, in an attempt to find patterns in human behaviour.

Self-interest versus the common good

It’s very tempting to be guided by self-interest: keeping vital information to yourself, making 

Research on behavioural economics: how much money do you put in the pot?

Research on behavioural economics: how much money do you put in the pot?

long-distance flights whenever you like,not declaring income to the tax authorities. Yet we all benefit if everyone also thinks about shared interests. After all, if no-one paid taxes there would be no hospitals, and without cooperation there would be no profit.

Behavioural economics

Economics is based on conflict. To understand how people weigh up their decisions, you need insight into both economics and psychology. Leiden University offers research and teaching at the interface between these two fields. Behavioural economics is a new discipline where economics meets psychology, exposing the fundamental structures of human social behaviour. Insights from behavioural economics first started to be taken seriously by policy makers about eight years ago. It may have been because they were trying to motivate people to reduce energy consumption, or to minimise food waste. What are the strategies that work? This is the question that behavioural economists try to answer. In order to discover the principles of social decision making, psychologist and economist Eric van Dijk designs games. For example: in a group of experimental participants, everyone is given ten euros. Each of them must then decide how much of this to put into a collective pot. The total amount put in will be doubled and shared out equally among all the participants. Someone who decides to put nothing into the pot will lose the least of his/her own money and still gain just as much as the other group members from the doubled pot. In other words, a lucky winner. Unless, of course, all the other participants also decide to put nothing in. Then the whole group will miss out on a big reward.

Mutual dependence

Experiments of this kind are deliberately done in the laboratory, where the participants receive feedback via a monitor and do not see each other. Any context that might distract from fundamental choices between self-interest and other people’s interest is stripped away. After all, the experiment is not about who is environmentally aware, or whether participants like each other. The aim is purely to find out what mutual dependence does to a group of people. Negotiations, the effect of sanctions, trust… all these social phenomena can be modelled in a game. One of the surprising results of this kind of research is that different norms apply when participants have to contribute to a collective pot than when they can take from a collective pot. In the latter case, everyone takes the same amount and this is generally regarded as fair, even if some group members are richer than others. In the former case, however, people are expected to put in according to their means, therefore the rich more than the poor. Another Leiden discovery is that people are less inclined to give other people money in a negotiation situation than if they can just give it to them. In a negotiation situation, they try to get as much as they can for themselves. But if the other person has no power, people tend to be generous. It has also been found that economic sanctions for selfish behaviour can sometimes have the opposite of the desired effect, because they undermine people’s trust in each other.

Group behaviour: one for the team

Researchers at Leiden study group behaviour. One of their findings is that when people make sacrifices for another member of their group, it is probably instinctive. Insights of this kind enable us to better understand and influence the social processes in a neighbourhood or company.

We derive some of our identity from the groups with which we feel a connection: our family, circle of friends, department or sports team, for example. Leiden psychologists study group behaviour. They want to find out how an individual relates to the group, and what happens in the interaction between groups. With this knowledge, we will be more able to understand and influence the social processes in a neighbourhood or company, for instance.

Evolutionary advantage

Living together has given people many advantages. Close-knit groups, in which people support and complement each other, exchange favours and perform complex tasks together, find it easier to survive than solo individuals. But group dynamics can also be counterproductive. People are excluded or bullied, group members fail to cooperate properly, or groups make life difficult for other

Group behaviour: one for the team

groups..Leiden psychologists conduct experiments with behaviour, measure physiological responses and look inside the brain. They aim to obtain a fundamental understanding of the group processes that we see all around us: at school, in the village, in the mosque or at the office, with the ultimate goal of making such processes more controllable.

Group status affects heart rate

Psychologist Daan Scheepers conducts research on status differences between groups and group members’ responses to these differences. It is known that in a dominance contest the heart rate and blood pressure increase more in the members of the ‘inferior’ group than in the members of the dominant group. Scheepers discovered that it is not only the group status itself that is important here, but also how legitimate that status is. If rumours are spread during an experiment, suggesting that the low status was not legitimate – ‘people are cheating’, ‘ the referee is rubbish’ – then the members of the inferior group exhibit a better physiological response and they also perform better in the next round. The opposite effect can be seen in the members of the winning group. If their status was called into question, they felt less sure of themselves, which was reflected in their heart rate and blood pressure.

Altruism as instinct

Studies have shown that individuals are willing to sacrifice their self-interest if this benefits a member of their own group. Research is conducted in Leiden into the roots of this phenomenon. Is altruism a conscious, rational decision or an intuitive, almost instinctive response? Psychologist Carsten de Dreu has found indications for the latter. He discovered that experimental participants who make a decision favouring a member of their group do this faster than participants whose decision is in their own favour. And participants also make an altruistic decision faster if they are working on a cognitively demanding task, such as solving a maths problem, at the same time. This suggests that the altruistic decision to help a group member is an unconscious response. Giving priority to self-interest uses more cognitive capacity. De Dreu also discovered that when we make altruistic decisions the hormone oxytocin activates the parts of the brain where our emotions are regulated, and not the parts where rational consideration takes place. It seems that solidarity with fellow group members has become deeply rooted in our brain during the course of evolution.

Group interests: rights of indigenous peoples

Industrialised countries extract natural resources in the territories of indigenous peoples, and appropriate the knowledge and culture of these peoples. Leiden anthropologists work to protect the rights of indigenous peoples. Their knowledge and advice enable governments to source sustainable products.

The affluent lifestyle in industrialised countries demands enormous quantities of natural resources, . resources that are often extracted in the territories of indigenous peoples, thus endangering their way of life. And companies in industrialised countries also appropriate the knowledge and culture of these peoples, while giving nothing in return. Leiden anthropologists research the interaction between indigenous peoples and other parties, and how the rights of these peoples are handled in practice.

The Agta in the Philippines. Photo: Gerard Persoon

The Agta in the Philippines. Photo: Gerard Persoon

Nickel and chromium in the rainforest

Mayo Buenafe – herself a Native Filipina – is conducting PhD research with the Agta, a nomadic people who live as hunter-gatherers in the tropical rainforest on the most northerly island of the Philippines. The Agta are dependent on water; rivers and the sea give them drinking water, food and transport routes. Buenafe wanted to research their language, traditions and management of water resources, but found herself in a conflict between the Agta and a mining company. This company has a permit to mine nickel and chromium in the Agta’s territory, and its activities are polluting the water and endangering the livelihood security of the native people. The interest of rich consumers in the cheapest possible products is here in conflict with the Agta’s right to live in their own way on their own land, or at least to receive financial compensation.

The voice of the Agta

Buenafe followed the Agta during their protest actions, recorded the events and became indirectly involved in a court case brought by human rights activists to make the mining company compensate the Agta. After obtaining her PhD, she hopes to go back to the Agta and share the results of her research with them. She would like to produce a video in which the ancient Agta traditions are recorded for future generations and to organise workshops with non-indigenous administrators. Buenafe hopes that, as a result, when officials are making new plans for the area, the voice of the Agta will be heard.

Intellectual property

Not only natural resources, but also the culture and knowledge of indigenous peoples are simply appropriated by industrialised countries, often without payment. Artists from affluent countries draw freely on ‘ethnic’ music and art, which are not protected by copyright. In 1998 a British pharmaceutical company patented the cactus plant Hoodia Gordonii, used for centuries by the South African San or Bushmen as an appetite suppressant. The company wanted to use it to combat Western obesity, without respecting the San’s intellectual property. The Leiden anthropologist Gerard Persoon is one of the researchers who for several decades have been studying inequality of this kind worldwide, and publishing the results. There is now better protection of the rights of indigenous peoples, for example through the United Nations Declaration on the Rights of Indigenous Peoples (2007). Persoon is currently researching what effect such declarations have in practice.

Sustainable timber

The specialist knowledge of anthropologists about relatively inaccessible areas and cultures makes them valuable consultation partners for organisations where sustainability is a high priority. For instance, Gerard Persoon is a member of the Dutch government’s Sustainable Timber Committee, which reports to the Minister for Infrastructure and the Environment, who is responsible for buying sustainable timber on the government’s behalf. In which countries are forest workers provided with decent housing and sufficient food? Where are the rights of indigenous peoples respected? Persoon is able to give a realistic answer to these questions. This process has helped to achieve a substantial increase in the use of ecologically and socially sustainable timber in the Netherlands.

A mining company at work in the territory of the Agta. Photo: Gerard Persoon

A mining company at work in the territory of the Agta. Photo: Gerard Persoon

Interests of states: insight into global politics

All players on the world stage operate strategically in order to safeguard their interests. Political scientists at Leiden University cast light on this volatile interplay of forces. Their research helps voters, NGOs, governments and international organizations make smart choices in this complex and rapidly changing world.

States in a globalizing world

How can human rights and human dignity be protected in a world so often plagued by violence and intolerance ? Are authoritarian regimes regaining the initiative? Will the European Union overcome the multiple challenges of economic change, human migration, geopolitical turmoil and voter discontent? How can interconnected societies deal with violent extremism? What factors shape the foreign policies of rising democratic powers like Brazil and India? These are just some of the critical questions being addressed by political scientists at 

Eleanor Roosevelt showing the Universal Declaration of Human Rights (Wikipedia Commons)

Eleanor Roosevelt showing the Universal Declaration of Human Rights (Wikipedia Commons)

Leiden University. Their research helps voters, NGOs, governments and international organizations make smart choices in this complex and rapidly changing world.

How to promote respect for human rights?

Since the Holocaust and the end of the Second World War, governments have negotiated and signed many treaties committing them to treat all people humanely. Leiden political scientist Daniel Thomas has conducted ground-breaking research on how these treaties empower activists and social movements pressing for change by authoritarian states. Focusing on the contribution of the 1975 Helsinki Accords to the demise of Communist rule in Eastern Europe and the Soviet Union,  Thomas found that international human rights norms provide a language of reform that is accessible to a wide range of societal actors and a legal justification for their reform efforts that is difficult for the state to repudiate, even when its rulers prefer to maintain the status quo. This ‘Helsinki-effect’ explains that even though international law provides no quick-fix for the problem of repressive rule, it can transform the terms of debate between state and society and thereby lay the groundwork for enduring political change.

Interests of states: insight into global politics

Authoritarian regimes are however not passive and Thomas is now examining their efforts to reverse the Helsinki effect by reclaiming the agenda in international law and institutions.

Can the Responsibility to Protect be regarded as an international norm?

Where human rights treaties are binding, the Responsibility to Protect (R2P) is not the governing principle. Nonetheless, R2P makes a real contribution to making the world a fairer place by defining what ‘should’ happen. A state is expected to protect its inhabitants against mass genocide and war crimes, for instance. University lecturer Theresa Reinold studies the role of influential states, such as America, in promoting R2P as an international norm and the implications of this standard for state sovereignty and international legislation. According to Reinold, R2P cannot yet be regarded as an international norm because it is not clear what such a norm should comprise of. Nor is it clear whether the international community bears the same

responsibility as the host country and exactly what powers are needed  to protect citizens. In spite of this lack of clarity, Reinold believes that R2P has ensured that it is difficult for the international community to ignore humanitarian crises when they occur.  Similarly, states that violate human rights cannot assume that they will not be subject to intervention from outside.

Will the EU survive?

Long considered a bulwark of peace and prosperity in Europe, the European Union (EU) is now wracked by multiple and seemingly intractable crisis. Leiden political scientist Hans Vollaard is examining whether and how the EU might collapse. His conclusion is clear: most member states will stay in the EU, as they do not see a proper alternative outside it, however critical they are 

Interests of states: insight into global politics

about the present EU. On the other hand, member states might cut their financial contribution to the EU or refuse to comply with EU principles and legislation. So while Vollaard expects the EU will muddle through its current difficulties, it could emerge as a less tightly integrated union.

What is the threat posed by violent extremism and how can inter-connected societies protect themselves?

Almost every day we hear reports in the media on the threat to individual security and social stability posed by violent extremists in Europe. “Radicalisation” and “violent extremism” are new ways to label the old phenomenon of political violence, says Leiden political scientist Francesco Ragazzi, who studies whether counter-terrorism policies may have unintended and undesirable effects. Recent policy responses to terrorism in Europe have tended to focus on one specific group of the population, which exacerbates polarization, exclusion and marginalization, and may thereby reinforce the problem of violent extremism. Furthermore,  as these policies increasingly reach beyond the traditional scope of law enforcement to involve teachers, doctors, social workers, and religious leaders, they pose serious questions about how violent groups’ activities can be disrupted while preserving the freedom of expression, education and religion that are the basis of democratic societies.

What factors shape the foreign policies of rising democratic powers like Brazil and India?

Though most observers agree that emerging powers will play a major role in the twenty-first century, the fact that Brazil and India are democracies has been overlooked in the rush to study China. Leiden political scientists Nicolas Blarel and Niels van Willigen are studying how regional parties use their leverage in political coalitions to shape the country’s foreign policy orientation, resulting in policy outcomes that are difficult to predict. Insights from the Indian experience could help understand the foreign policy choices of other states that emerged from authoritarian rule (Bangladesh, Brazil, Indonesia and Pakistan) or that transitioned to coalition government after a long period of democratic but single party rule (Japan, Mexico).


Scientists working in this multidisciplinary research area

  • Violet Benneker Msc
  • Nicolas Blarel
  • Mayo Buenafe
  • Carsten de Dreu
  • Eric van Dijk
  • Wilco van Dijk
  • Corinna Jentzsch
  • Erik de Kwaadsteniet
  • Esther van Leeuwen
  • Sabine Luning
  • Tessa Minter
  • Emma ter Mors
  • Gerard Persoon
  • Theresa Reinold
  • Daan Scheepers
  • Daniel Thomas
  • Hans Vollaard
  • Ekoningytas Wardani
  • Niels van Willigen

Violet Benneker MscPhD candidate in Political Science

Topics: Human rights, social norms, and conflict in the Middle East

+31 (0)71 527 2727

Nicolas BlarelUniversity Lecturer in Political Science

Topics: International relations, foreign policy analysis, security studies, South Asian politics

+31 (0)71 527 3952

Mayo BuenafePhD candidate in Cultural Anthropology and Development Sociology

Topics: Indigenous knowledge systems, water use and management, food and water security, Agta hunter-gatherers, Philippines

+31 (0)71 527 2727

Carsten de DreuProfessor of Social Sciences

Topics: Group processes, love within groups, conflict

+31 (0)71 527 2727

Eric van DijkProfessor of Social and Organisational Psychology

Topics: Negotiation, social dilemmas, decision making, behavioural economics

+31 (0)71 527 3709

Wilco van DijkProfessor of Psychological Determinants of Economic Decision Making

Topics: Conflict between self-interest and group interest

+31 (0)71 527 6844

Corinna JentzschUniversity Lecturer in Political Science

Topics: Civil wars, community mobilisation against violence

+31 (0)71 527 3456

Erik de KwaadstenietUniversity Lecturer in Social and Organisational Psychology

Topics: Social dilemmas, tacit coordination

+31 (0)71 527 4109

Esther van LeeuwenUniversity Lecturer in Social and Organisational Psychology

Topics: Intergroup helping, employer loyalty, corporate reputation, intergroup relations

+31 (0)71 527 1303

Sabine LuningUniversity Lecturer in Cultural Anthropology and Development Sociology

Topics: Africa, economics, religion, corporate social responsibility, resource politics

+31 (0)71 527 6614

Tessa MinterUniversity Lecturer in Cultural Anthropology and Development Sociology

Topics: Southeast Asia, Agta hunter-gatherers, livelihood strategies, adaptation to environmental change, environmental decision making

+31 (0)71 527 3816

Emma ter MorsUniversity Lecturer in Social and Organisational Psychology

Topics: Attitudes, information processing, trustworthiness, acceptance of decisions

+31 (0)71 527 4075

Gerard PersoonProfessor of Cultural Anthropology and Development Sociology

Topics: Environmental anthropology, nature conservation, human-environment interactions, natural resources management

+31 (0)71 527 6826

Theresa ReinoldUniversity Lecturer in Political Science

Topics: International relations theory, international law, African Union, security studies

+31 (0)71 527 6869

Daan ScheepersSenior Lecturer in Social and Organisational Psychology

Topics: Group processes, intergroup relations, identity, psychophysiology, challenge and threat

+31 (0)71 527 3642

Daniel ThomasProfessor of International Relations

Topics: International relations, politics of international law, politics of human rights, international organisations, humanitarian intervention

+31 (0)71 527 1263

Hans VollaardUniversity Lecturer in Political Science

Topics: EU policy, process of integration and disintegration

+31 (0)71 527 4673

Ekoningytas WardaniPhD candidate in Cultural Anthropology and Development Sociology

Topics: Food security, indigenous peoples, Southeast Asia, rural and agricultural development, sustainable livelihood

+31 (0)71 527 3961

Niels van WilligenUniversity Lecturer in Political Science

Topics: United Nations, international security operations

+31 (0)71 527 3632


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Leiden University has a long tradition of teaching in the area of the social sciences. The Faculty of Social and Behavioural Sciences offers students a thorough social science training in the disciplines of cultural anthropology, education and child studies, political science and psychology. The bachelor’s programmes provide students with a strong scientific basis to prepare them for leading positions in a complex society. They are trained as researchers, and learn skills that are invaluable for careers both within and outside the academic world.

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