Although some species, such as ants, have an instinct to cooperate, I believe that it is only humans who have the ability to influence others’ choices concerning whether or not to co-operate. Moreover, I believe that it is the use of this ability that has made civilization possible. There is a quip in psychology that you never see two chimpanzees help one another carry a log. Humans are the primate species with the ability to cooperate in complex, sophisticated ways.

I claim here that humans have a fundamental rule of social morality, which is: Reward cooperators; punish defectors.1 The use of this rule is what enables humans to work effectively with strangers, making possible sophisticated economies and civilizations. However, this rule can cause problems when people mis-classify the social actions of others.

See Prisoners’ Dilemma, by Avinash Dixit and Barry Nalebuff, in the Concise Encyclopedia of Economics.

Generally, a cooperator is someone who obeys social norms without requiring coercion. A defector is someone who takes advantage of others by disobeying social norms. I borrow the terms cooperator and defector from game theory, as in the prisoners’ dilemma. In such games, each individual faces a choice. You can either do what is best for everyone (cooperate) or do what is best for yourself (defect). There is a better outcome when everyone chooses to cooperate, but there is a challenge in getting people to arrive at that outcome, because for each individual it appears to pay to defect.

Consider a circumstance where we might cooperate or defect. On a crowded subway, an elderly man or perhaps a pregnant woman gets on board. A cooperator will give up his or her seat. A defector will not. In this situation, if you give up your seat, others on the subway are apt to smile at you and say, “That’s nice.” If you refuse to give up your seat, others are likely to scowl at you and mutter curses. Their approval or disapproval follows what I am calling the fundamental rule of social morality.

In fact, people offer more than just verbal approval and disapproval. When you believe that you have been well treated in a commercial transaction, you will return to that business and encourage your friends to do so. Conversely, when you feel that you have been treated poorly, you will refuse to patronize that firm again, and you will tell friends to avoid it, too. I am sure that the reader can come up with many other examples of behavior that constitutes rewarding cooperators and punishing defectors.

In a modern society in which we must deal with strangers, we use signals to help us distinguish cooperators from defectors. In social interactions, our willingness to follow certain rituals, such as shaking hands, works as a signal that we accept social norms and can be trusted as cooperators.

Ara Norenzayan’s book, Big Gods,2 argues that belief in a powerful supernatural being with “policing powers” makes a person cooperative. Taking this one step further, if we know that people with the fear of God are likely to be cooperators, then we will look for signals that people have such a fear. Their willingness to follow religious rituals and to wear religious symbols becomes an important signal of cooperation.

See Crime, Education, and the NLSY: The Role of the Sheepskin Effect, by Bryan Caplan, EconLog, November 7, 2014.

Similarly, Bryan Caplan, writing on EconLog, argues that obtaining a college degree is a way to signal one’s willingness to obey social norms. Thus, the “sheepskin” becomes a signal that one is more likely a cooperator rather than a defector.

The principle of rewarding cooperators and punishing defectors can be extended to rewarding people who reward cooperators and punishing people who fail to punish defectors. That is, you are considered a cooperator if you are observed praising cooperators, and you are considered a defector if you are seen as acting tolerantly toward defectors.

For example, I have been on an airplane where the flight attendant announced that there were passengers on board who were serving in the military and asked us to give them a round of applause. If I had not joined in the applause, I would have felt like a defector, because I was not rewarding the cooperators (the military personnel).

Praising military personnel for “service to our country” and saying that deserters ought to be shot is an example of people following the fundamental rule of social morality. Serving in the military represents cooperation and deserting the military represents defections. However, a committed pacifist might have a different point of view. Or consider that if a military unit undertook a cruel massacre, then it could be the deserter, not the loyal member, who truly deserves praise.

“The fundamental rule of social morality can lead us astray whenever our intuition is mistaken.”

More generally, the fundamental rule of social morality can lead us astray whenever our intuition is mistaken about who is a cooperator and who is a defector. Unfortunately, I believe that this occurs quite often.

For example, our instinct seems to be to regard wealthy people as defectors. They have “taken” more than “their share” of economic bounty. Notwithstanding this instinct, however, their wealth could readily come from engaging in many transactions with people, each of which left the other parties better off. The owners of Walmart provided goods at low cost to millions of consumers. The founders of Apple, Google, and Facebook also succeeded by delighting tens of millions of customers.

Meanwhile, we seem to assess whether politicians are cooperators or defectors based on criteria of group affiliation or attachment to a cause. Many people regard politicians as defectors if they do not “support education.” In this case, a cooperator is someone who is eager to spend other people’s money on education, and a defector is someone reluctant to do so.

Indeed, the way that I look at it, this fundamental rule of social morality gets manipulated and abused often in the political context. Demagogues are very good at stimulating our sympathy for cooperators and our antipathy toward defectors. Meanwhile, however, the complexity of society seems to make it difficult to determine who is truly a cooperator and who is truly a defector.

Deirdre McCloskey, in books such as Bourgeois Dignity,3 argues that the social approbation of commerce was important in unleashing the Industrial Revolution. In terms of what I call the fundamental rule of social morality, you can only have capitalist development if people are able to treat merchants as cooperators rather than automatically viewing them as defectors.

For more on these topics, see the EconTalk podcast episode

Gordon on Ants, Humans, the Division of Labor and Emergent Order.

A major concern that I have with contemporary norms pertains to the notions of profit and non-profit. I see many young people who view working for a non-profit as inherently representing cooperation, while working at a for-profit firm carries with it a presumption of defection.

In fact, the truth might be the opposite. For-profit firms must serve customers, which means that they are necessarily providing goods and services that improve people’s lives. Non-profit organizations must only serve donors, and the goods and services that these organizations provide to clients may not actually be helpful.

In conclusion, the fundamental rule of social morality has its perils. On the one hand, it is what enables social norms to “stick,” binding humans together. On the other hand, unless our understanding of what constitutes cooperation and what constitutes defection is reasonably accurate, rewarding cooperators and punishing defectors has the potential to do more harm than good.


In my previous column “Libertarians and Group Norms,” I discussed various other thinkers on this topic.

Ara Norenzayan, Big Gods: How Religion Transformed Cooperation and Conflict. Princeton University Press, 2015.

Deirdre McCloskey, Bourgeois Dignity: Why Economics Can’t Explain the Modern World. University of Chicago Press, 2011.


*Arnold Kling has a Ph.D. in economics from the Massachusetts Institute of Technology. He is the author of five books, including Crisis of Abundance: Rethinking How We Pay for Health Care; Invisible Wealth: The Hidden Story of How Markets Work; and Unchecked and Unbalanced: How the Discrepancy Between Knowledge and Power Caused the Financial Crisis and Threatens Democracy. He contributed to EconLog from January 2003 through August 2012.

For more articles by Arnold Kling, see the Archive.