The Fragility of International Cooperation

Stable cooperation requires trust and verification.

Posted Sep 14, 2020

The United States has recently made a number of unilateral decisions with some of its closest allies—including unilateral announcements closing borders to international travel to slow the transmission of COVID-19, and unilateral declarations pulling the U.S. out of cooperative treaties that range from the Paris Climate Accord to missile treaties with the Russians. And then there’s recent talk of the U.S. pulling out of NATO, upending a 75-year joint defense pack that brought together both allies and former adversaries that ultimately was influential in European reconstruction and security after World War II.

We study the evolution and maintenance of cooperation in animals and know that we should be cautious when it comes to breaking cooperative agreements and alliances because they are remarkably fragile—easy to break but potentially difficult to restore. The benefits of cooperation can be tremendous, but when your society depends on those benefits, the breakdown in cooperation can be catastrophic. If you’ve seen the TV series Meerkat Manor, you’ll know how the survival of an entire clan can turn on the effectiveness of cooperation. And in the long, cold, actuarial logic of natural selection, animals evolve to shun cooperative ventures that don’t provide them with tangible benefits. Chimpanzees prefer to cooperate with individuals they know “cooperate well.” And why not? Crucial tasks require reliable partners.

The economics of cooperation are clear: individuals should cooperate when the payoff to cooperating exceeds the payoff to not cooperating. Many species face common predatory threats and work together to eliminate the threat much in the same was as competitive nations form an alliance against a common threat. In nature this sometimes leads to initially counter-intuitive alliances. For instance, competitors are often seen cooperating to chase predators away. You’ve probably seen this in the spring when a number of smaller species, like chickadees, nuthatches, and titmice join together to chase a crow or raven away from their nests. Such inter-species mobbing behavior is risky but it benefits all individuals. Changes in the vulnerability of an actor in these circumstances changes the benefits of cooperation.

But cooperative systems are ripe for exploitation. After all, wouldn’t it be better to let someone else do the work and experience the risks associated with predator mobbing? All cooperative systems can tolerate some cheating, but with too many cheaters, the system falls apart. One way to stabilize a cooperative venture against cheaters is to identify them, and punish them quickly.

The late Nobel Prize winning economist Elinor Ostrom’s pioneering work on human cooperation identified a number of key principles about common pool resource management. Whether it was water use in competing Southern California municipalities, or managing an artesian fishery with a number of competing independent fishing boats, for people to cooperate, they needed information about the behavior of others, and they needed immediate punishment of those that violated agreed upon quotas. Effective punishment, Ostrom found should be both immediate, scalable, and forgiving.

Yet trust and reputation are built up over time, they are Bayesian processes. Too many violations leads to reduced trust and reduces one’s reputation. Even yellow-bellied marmots know this. Experiments have shown that when they hear another marmot alarm calling when no predator is around, their assessment of that individual’s reliability decreases. Marmots, it turns out, have the ability to evaluate the reliability of others! Remarkably, further experiments have shown that when they hear a reliable caller making a mistake, they look up briefly, but then get back to what they were doing. “Trust but Verify” has its roots in our non-human ancestors.

But there’s a catch. Small birds, and probably even marmots, have a fairly limited ability to remember who’s who—which individuals played the game fairly last time, and who cheated. Forgiveness is very easy when you can’t remember who the guilty party was, and this forgiveness stabilizes the cooperative venture. Not so with all species. Chimpanzees have to remember large amounts of information on social interactions: who fought with whom, who won, and importantly, who helped in the fight, and who chickened out. Cheaters and cowards are identified and remembered by all. Partly as a result of this, chimpanzee societies are prone to violent upheavals – dominance hierarchies can be overturned in a day, and the social order needs to be rebuilt from scratch. As you can imagine, this is all the more so in human society.

Animals are more likely to be trusting and forgiving of cheaters and scroungers when they share a common interest—lions in the same pack, for example, who stand to lose everything if their territory is overrun by rivals. But when groups are competing, as nation states do, there is little incentive to be quite so forgiving of each other.

The world is a safer place because of international defense alliances, and such alliances are going to be essential in solving the existential threats caused by climate change. Repeatedly violating alliances is likely to reduce the reputation of the nation who violates them and this will reduce the perceived benefits of cooperation. After all, who wants to cooperate with a cheater? In nature, a group of animals whose cooperation is undermined by cheating may die out. This is not the result we hope for humanity. In the realm of international relations immediate and forgiving punishment may help maintain a relationship. But imposing tariffs and boycotts are longer-lasting punishments and may further degrade a relationship, creating a positive feedback that will accelerate the loss of cooperation.

NATO was created in the ashes of WWII and brought together former adversaries. Missile treaties were created to address the on-going existential civilization-killing threats associated with nuclear weapons and have successfully reduced US and Soviet/Russian arsenals. We’ve learned from animals that conditions to create alliances are not always present. Thus, keeping existing alliances intact may ultimately be more beneficial than breaking them apart and hoping to create a new one at a moment’s notice.


This is co-authored with my colleague, Arik Kershenbaum who is a college lecturer, tutor and director of studies at Girton College, Cambridge University and the author of The Zoologist’s Guide to the Galaxy.

Please cite this as: Blumstein, D.T., and Kershenbaum, A. (2020). The fragility of international cooperation. Psychology Today, URL.

Goodall, J. (2010). Through a window: My thirty years with the chimpanzees of Gombe. HMH.

Grinnell, J. (2002). Modes of cooperation during territorial defense by African lions. Human Nature, 13(1), 85-104.

Melis, A. P., Hare, B., & Tomasello, M. (2006). Chimpanzees recruit the best collaborators. Science, 311(5765), 1297-1300.

Ostrum, E. (1990). Governing the commons: the evolution of institutions for collective action. Cambridge University Press.