Classroom Materials

Sustainability and Behavior

Global goals require collective action

Today's global society faces major challenges in achieving the Sustainable Development Goals, including sustainable resource use, social equality, and providing access to good education, health and human well-being for all.

Image source: UN Department of Public Information (Guidelines)

Which sustainable development goals are most important to humans in the world? Which goals are most important to you?

In a global online survey of the United Nations people can submit their opinions.

Classroom ideas:

  • Students in the class submit their anonymous responses, and the whole class analyses the results (creating a bar chart).

  • Afterwards, the results of the class are compared with the global results, or with the results of your own country or other subgroups. What similarities and differences are there? Why could the results of this survey be different between different groups of humans?

  • What do the results of this survey tell us about the challenges and opportunities for addressing global sustainability issues (e.g. climate change)?

These challenges require an unprecedented level of cooperation at every level of society, including the global scale. What can we learn from the communities of the world, from our evolutionary history, from our everyday behaviors and experiences, and from other living beings about how to navigate these challenges of cooperation? Research from biology, psychology, economics, anthropology, behavioral and sustainability science provides insights into the conditions and principles for sustainable cooperation across a diversity of contexts. In this light, an understanding of the origins and complex dynamics of human social behavior can help students understand today's challenges of collaboration and collective problem-solving around our shared interests in a better future.

Teaching Materials Database

This database contains all of our current teaching materials related to Sustainability and Behavior, which are featured on this page further below.

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The "Tragedy of the Commons" and strategies for sustainability

Sustainable development is about working together to create and sustain shared natural and social resources .

Common-pool resources (also known as a commons) are resources that are shared by a community and are limited in some way. Often, the more someone uses the resource, the less there is left for the others in the community. Examples of commons are groundwater supplies, fisheries, forests, the atmosphere, public roads and parks, the budget of a community project, even the amount of time in a classroom can be considered as a shared resource in this way. There is often a dilemma in using such resources: the individual may have an interest in using as much of the resource as possible (or contributing as little as possible to preserving the resource or achieving a project's goal). After all, their behavior has no immediate negative consequences. Problems can arise when too many people in the community do so, potentially endangering the entire resource, with negative consequences for all.

This is called the 'tragedy of the commons', an important concept in evolutionary, behavioral, and sustainability sciences.

Many communities rely on a shared or common-pool resource (the 'commons'). What prevents some individuals from taking as much of the resource as possible?
If some are taking more from the resource, this entices others to increase their resource use as well. After all nobody wants to be "the fool".
However, if everyone takes more and more, resource availability is jeopardized for all. This is the tragedy of the commons.

The ecologist Garret Hardin popularized the dilemma of the commons in a 1968 published article "The Tragedy of the Commons", using the example of a village pasture shared by several farmers. Hardin suggested that there are only two possible solutions to ward off tragedy: enforcing rules by a central government ("Freedom in the commons brings ruin to all."); or privatization of the resource ("Private property plus inheritance is injust... but injustice is preferable to total ruin.").

Hardin assumed that in a situation of common usage, we can not simply rely on the conscience or "moral feelings" of individuals. After all, selfish individuals would have a (selective) advantage, and conscientious users would be exploited.

Garret Hardin

Image source: Garret Hardin Society

However, in the 1990s, political scientist Elinor Ostrom and colleagues studied a variety of commons around the world, such as fisheries, shared irrigation systems, forests, and pastures. She wanted to find out how communities in the world manage their common resources, and to what extent they are able to ward off the tragedy of the commons.

She found that certain factors and conditions, including of the user's resource and social circumstances, as well as user community institutions and behaviors have a strong impact on whether communities can successfully use and manage their resource in a sustainable way. From her work, Elinor Ostrom identified eight important "design principles" for the management of community resources.

Evolutionary biologists and anthropologists have recognized that these design priniciples can be transferred to understand cooperation among various human groups and other living beings more broadly.

In 2009, Elinor Ostrom was the first woman to receive the Nobel Prize in Economics for her work on understanding democratic strategies for solving the tragedy of the commons across so many contexts.

Elinor Ostrom

Image Source: Holger Motzkau 2010 / Wikipedia/Wikimedia Commons / CC BY-SA 3.0

Ostrom's 8 principles for successful cooperation

1 Group identity and common goals: It is clear and accepted locally, who belongs to a group, and all members have common goals.

2 Fair distribution of costs and benefits: The costs incurred by members of a cooperation are distributed in proportion to their benefits from the cooperation.

3 Collaborative decision-making: Most individuals in the group can participate in decisions that affect them, set or change the rules of the game.

4 Monitoring agreed upon behaviors: The community observes and monitors how a resource is used by all, how its condition develops, whether everyone behaves according to the rules, and to what extent common goals are achieved.

5 Graduated responding to helpful and unhelpful behavior: Rewards for valued behaviors and sanctions for misbehaviors start at a low level (e.g. friendly discussion), and are increased in proportion to the contribution or detriment of the behavior towards the group.

6 Fast and fair conflict resolution: There are local arenas and mechanisms for the quick, efficient and direct resolution of conflicts among members or with other groups.

7 Recognition of rights and autonomy: the group has a minimum of rights to set its own rules in relation to its sphere of common purpose.

8 Nested institutions: Groups are nested on many levels, with each level requiring principles 1-7 (polycentric governance).

Depending on context, further auxilliary principles can be important for group cooperation.

Source: adapted from Wilson, Ostrom, Cox (2013) ; Atkins, Wilson, & Hayes (2019)

Further environmental and socio-political conditions, as well as factors of the resource and user community, can influence how easy or difficult it is for a community to implement the principles of cooperation and sustainable resource management.

We can explore how these factors interact through real-world case studies, as well as through computer simulations and experiments that model specific dynamics in common-pool resource situations.

Source: adapted from Ostrom, E. (2009).

The importance of social emotions and intuitions for human behavior

Homo oeconomicus or Homo sapiens?

For a long time in economics, the model of homo oeconomicus was considered an acceptable approach to describing human nature and behavior: According to this model, humans are mostly self-serving, rational maximizers of material profit, primarily interested in drawing as much of it as possible from the environment and from relationships with others in the short term. If one wants people to behave in a certain way, one only has to create enough material incentives, e.g. through discounts, bonuses, penalties, taxes, etc.

Garrett Hardin's prediction that the sustainable use of a common-pool resource can be realized only through privatization or central government was based on the assumption that people generally act in the pattern of Homo oeconomicus.

However, in the last two-three decades, this model and its utility has been more and more questioned. The research field of behavioral economics has begun to investigate how people actually behave in relationships and interactions with other people - does their behavior reflect the model of Homo oeconomicus?

Some findings from behavioral economics:

  • Humans often do not act as "selfishly" as had been assumed. Humans seem to care about having a good conscience, prosocial values ​​and respecting social norms. Humans do not seem to be only striving for material profit. Even the meaning of the terms "selfishness" and "altruism" had to be rethought (e.g. is it selfish when someone helps another person because it feels good?).

  • Humans often do not act as "rationally" as had been supposed. People often act intuitively, guided by (social) emotions, intuitions and internalized social norms (e.g. an intuitive sense of "How do others around me behave? What behavior do others expect from me?"). Even the meaning of the term "rationality" had to be rethought (e.g. is it irrational if someone acts by a gut feeling, when the consequence of the action nonetheless contributes to the person's long-term well-being?)

  • Humans care a lot about what other people think of them and their social identity. Humans care about status, standing out and/or fitting in.

  • Humans are often (but not always) capable and willing to organize collectively for the common good (e.g. for the sustainable use of community resources, or contributing to the creative commons), without private property or top-down management, and they accept personal costs for doing it.

  • Material incentives (e.g. monetary rewards) can "backfire" or become a "self-fulfilling prophecy". People can become material profit maximizers (i.e. homo economicus) if they feel that other people are also self-interested material maximizers or if it is perceived that social preferences, values ​​and social norms do not matter to other people around them.

Most of these findings are actually familiar to us from our own everyday experience.

The question is what factors influence people's behavior - what role do emotions, beliefs and intuitions, individual experiences, genes, growing up in a particular social and cultural environment with certain norms, institutions, and technologies, and immediate environmental conditions play? And how can or should we use answers to these questions to promote the achievement of societal goals for human well-being and sustainable development?

The death of Homo economicus

Interview with behavioral and evolutionary economist Sam Bowles

Nudging human behavior

Our behavior is strongly influenced by external environmental conditions, even if we are often unaware of it.

In behavioral economics, the method of nudging uses this fact. Nudging is a method of predictably influencing people's behavior without resorting to "carrot and sticks" methods like direct prohibitions, imperatives, or economic incentives, but rather by slighly changing environmental conditions or messages in order to nudge people's intuitions. The goal of behavioral change should be in the interest of the affected individuals and/or in the interest of wider society. Thus, e.g. cigarette advertising is not a nudge (because the intended behavior is mainly in the interest of the cigarette manufacturer), while warnings on cigarette packets are nudges (because the desired behavior is in the long-term interest of the affected individual and society). Those nudges that aim to promote more environmentally friendly or sustainable behavior in people, are often called green nudges.

The justification of nudging lies in the fact that human behavior is strongly influenced by unconsciously perceived environmental stimuli, whether we like it or not. Thus, the strategic change of environmental factors may help people to make decisions and behave more according to their actual goals and values.

However, the principle of nudging is also much debated and criticized because it lurks the danger of justifying behavioral manipulations that may not correspond to the interests and values ​​of those affected.

(There is also a philosophical question around the concept of "autonomy" - what do insights of cognitive and neuroscience tell us about how much of a "free will" or autonomy we really have...)

more on this:

Behavioral scientists study through which measures we can influence people's behavior concerning their use of resources: to what degree do financial incentives, social norms, or moral appeals influence their behavior?

Transcript English

Ted Talk with subtitles

Possible discussion questions:

  • Is the method of nudging ethically questionable because the behavior of people is deliberately manipulated, or is it harmless or even desirable because the aim is to nudge people without coercion towards prosocial or other positive behaviors, without causing physical or psychological harm?

  • Could the method of nudging be enough in order to change people's behavior towards sustainabiltiy? What might be the additional role of helping people to consciously change their behavior, for example by raising people's awareness about the factors that influence human behavior, or by helping them reflect on their personal values?

  • Think about how many nudges you encounter in your environment everyday. Think for example about your way to school (information signs, signposts, warnings, billboards?), various places in the school (laboratory, toilet, cafeteria, courtyard, doors?), supermarket (signs, display of items?), your home (notepad, calendar entries , shopping list?). Students may be asked to collect and document a series of nudges they encounter in their daily lives as homework assignments and share them with the class.

    • Are there any examples that you were not aware of before?

    • What effect may these environmental influences have on your behavior?

    • Which examples may not be nudges because they have the goal of influencing your behavior against your own and community (long-term) interests and values?

  • How could one use the method of nudging for oneself to change one's own behavior in a direction that is in one's own interest (e.g. to change habits, live a healthier or more sustainable lifestyle, learn new things, remember things better, ...)?

Our moral intuitions

Sense of fairness

Fair distribution of resources, costs and benefits among members, as well as fair processes of decision making and conflict resultion, are among the conditions for the sustainable development of a community (see above, Ostrom's principles 2, 3, 5, 6).

Because of the importance of group life in the course of human evolution, a sense of fairness is part of our evolutionary heritage. Our sense of fairness is one of our human "moral intuitions". Almost all people, regardless of their culture or social background, seem to have a sense of fairness, even if groups and humans vary in how it manifests itself and in what situations it is expressed.

What seems fair is often dependend on the context, the affected group, and one's own role in a situation. For example, people care about fairness in relation to different kinds of groups, sometimes people care more about fairness as "equal benefits for everyone", sometimes people care more about "benefits in proportion to contribution", sometimes people care more about "more benefits for those in need", and probably many of us feel something in between depending on the situation. Because of these different and context-dependent meanings of fairness, there is often disagreement between people about what is"fair". In many conflicts in everyday life and in society, our sense of fairness comes into play.

In addition to the sense of fairness, social psychologist Jonathan Haidt has identified a series of other, possibly universal, moral intuitions of humans around the world. These moral intuitions shape our reasoning about what is good and bad, normal and unnormal, right and wrong, important and unimportant. Moral intuitions have a strong influence on our opinions and behaviors, especially regarding ethically-charged issues in human groups, including issues of sustainable development.

Understanding a little bit about how our evolved social brains process moral questions and ethical dillemmas provides one bridge to having a more flexible conversation about the complex issues that face every level of society.

Applying our understanding of human behavior towards well-being and sustainability

So through behavioral science, we now know about the conditions that favor or hinder humans to cooperate towards shared goals, including sustaining shared resources and many other sustainable development goals.

We also now know a lot about the aspects of human evolved behavior that favor or hinder humans to behave in a way that is best for themselves and everyone in the long term. Can we use this understanding to actually affect change in the world - in ourselves and in our communities?

Prosocial is one approach that is doing just that.

see more under:


  • Atkins, P. W. B., Wilson, D. S., & Hayes, S. C. (2019). Prosocial. Using Evolutionary Science to Build Productive, Equitable, and Collaborative Groups. Oakland, CA, USA: Context Press.

  • Basurto, X., & Ostrom, E. (2009). Beyond the Tragedy of the Commons. Economia Delle Fonti Di Energia e Dell’ambiente, 35–60.

  • Bateson, M., Nettle, D., & Roberts, G. (2006). Cues of being watched enhance cooperation in a real-world setting. Biology Letters, 2(3), 412–414.

  • Bowles, S., & Polanía-Reyes, S. (2012). Economic incentives and social preferences: Substitutes or complements? Journal of Economic Literature, 50(2), 368–425.

  • Cialdini, R. B., & Schultz, W. (2004). Understanding and motivating energy conservation via social norms. William and Flora Hewlett Foundation.

  • Cohn, A., Maréchal, M. A., Tannenbaum, D., & Zünd, C. L. (2019). Civic honesty around the globe. Science, 8712(June), eaau8712.

  • Felsen, G., & Reiner, P. B. (2011). How the neuroscience of decision making informs our conception of autonomy. AJOB Neuroscience, 2(3), 3–14.

  • Haidt, J. (2012). The Righteous Mind: Why Good People Are Divided by Politics and Religion. New York, NY, USA: Pantheon Books.

  • Hardin, G. (1968). The Tragedy of the Commons. Science, 162(June), 1243–1248.

  • Henrich, J., Boyd, R. T., Bowles, S., Camerer, C. F., Fehr, E., & Gintis, H. (2004). Foundations of Human Sociality. Economic Experiments and Ethnographic Evidence from Fifteen Small-Scale Societies. New York, NY, USA: Oxford University Press.

  • Koomen, R., & Herrmann, E. (2018). Chimpanzees overcome the tragedy of the commons with dominance. Scientific Reports, 8(1), 10389.

  • Koomen, R., & Herrmann, E. (2018). An investigation of children’s strategies for overcoming the tragedy of the commons. Nature Human Behaviour, 2, 348–355.

  • Ostrom, E. (2009). A General Framework for Analyzing Sustainability of Social-Ecological Systems. Science, 325(5939), 419–422.

  • Thaler, R. H. & Sunstein, C. R. (2008). Nudge: Improving Decisions About Health, Wealth, and Happiness. Yale University Press.

  • Wilson, D. S., Ostrom, E., & Cox, M. E. (2013). Generalizing the core design principles for the efficacy of groups. Journal of Economic Behavior and Organization, 90, S21–S32.