The evolution of human cooperation

Jun 17 JDN 2458287

If alien lifeforms were observing humans (assuming they didn’t turn out the same way—which they actually might, for reasons I’ll get to shortly), the thing that would probably baffle them the most about us is how we organize ourselves into groups. Each individual may be part of several groups at once, and some groups are closer-knit than others; but the most tightly-knit groups exhibit extremely high levels of cooperation, coordination, and self-sacrifice.

They might think at first that we are eusocial, like ants or bees; but upon closer study they would see that our groups are not very strongly correlated with genetic relatedness. We are somewhat more closely related to those in our groups than to those outsides, usually; but it’s a remarkably weak effect, especially compared to the extremely high relatedness of worker bees in a hive. No, to a first approximation, these groups are of unrelated humans; yet their level of cooperation is equal to if not greater than that exhibited by the worker bees.

However, the alien anthropologists would find that it is not that humans are simply predisposed toward extremely high altruism and cooperation in general; when two humans groups come into conflict, they are capable of the most extreme forms of violence imaginable. Human history is full of atrocities that combine the indifferent brutality of nature red in tooth and claw with the boundless ingenuity of a technologically advanced species. Yet except for a small proportion perpetrated by individual humans with some sort of mental pathology, these atrocities are invariably committed by one unified group against another. Even in genocide there is cooperation.

Humans are not entirely selfish. But nor are they paragons of universal altruism (though some of them aspire to be). Humans engage in a highly selective form of altruism—virtually boundless for the in-group, almost negligible for the out-group. Humans are tribal.

Being a human yourself, this probably doesn’t strike you as particularly strange. Indeed, I’ve mentioned it many times previously on this blog. But it is actually quite strange, from an evolutionary perspective; most organisms are not like this.

As I said earlier, there is actually reason to think that our alien anthropologist would come from a species with similar traits, simply because such cooperation may be necessary to achieve a full-scale technological civilization, let alone the capacity for interstellar travel. But there might be other possibilities; perhaps they come from a eusocial species, and their large-scale cooperation is within an extremely large hive.

It’s true that most organisms are not entirely selfish. There are various forms of cooperation within and even across species. But these usually involve only close kin, and otherwise involve highly stable arrangements of mutual benefit. There is nothing like the large-scale cooperation between anonymous unrelated individuals that is exhibited by all human societies.

How would such an unusual trait evolve? It must require a very particular set of circumstances, since it only seems to have evolved in a single species (or at most a handful of species, since other primates and cetaceans display some of the same characteristics).

Once evolved, this trait is clearly advantageous; indeed it turned a local apex predator into a species so successful that it can actually intentionally control the evolution of other species. Humans have become a hegemon over the entire global ecology, for better or for worse. Cooperation gave us a level of efficiency in producing the necessities of survival so great that at this point most of us spend our time working on completely different tasks. If you are not a farmer or a hunter or a carpenter (and frankly, even if you are a farmer with a tractor, a hunter with a rifle, or a carpenter with a table saw), you are doing work that would simply not have been possible without very large-scale human cooperation.

This extremely high fitness benefit only makes the matter more puzzling, however: If the benefits are so great, why don’t more species do this? There must be some other requirements that other species were unable to meet.

One clear requirement is high intelligence. As frustrating as it may be to be a human and watch other humans kill each other over foolish grievances, this is actually evidence of how smart humans are, biologically speaking. We might wish we were even smarter still—but most species don’t have the intelligence to make it even as far as we have.

But high intelligence is likely not sufficient. We can’t be sure of that, since we haven’t encountered any other species with equal intelligence; but what we do know is that even Homo sapiens didn’t coordinate on anything like our current scale for tens of thousands of years. We may have had tribal instincts, but if so they were largely confined to a very small scale. Something happened, about 50,000 years ago or so—not very long ago in evolutionary time—that allowed us to increase that scale dramatically.

Was this a genetic change? It’s difficult to say. There could have been some subtle genetic mutation, something that wouldn’t show up in the fossil record. But more recent expansions in human cooperation to the level of the nation-state and beyond clearly can’t be genetic; they were much too fast for that. They must be a form of cultural evolution: The replicators being spread are ideas and norms—memes—rather than genes.

So perhaps the very early shift toward tribal cooperation was also a cultural one. Perhaps it began not as a genetic mutation but as an idea—perhaps a metaphor of “universal brotherhood” as we often still hear today. The tribes that believed this ideas prospered; the tribes that didn’t were outcompeted or even directly destroyed.

This would explain why it had to be an intelligent species. We needed brains big enough to comprehend metaphors and generalize concepts. We needed enough social cognition to keep track of who was in the in-group and who was in the out-group.

If it was indeed a cultural shift, this should encourage us. (And since the most recent changes definitely were cultural, that is already quite encouraging.) We are not limited by our DNA to only care about a small group of close kin; we are capable of expanding our scale of unity and cooperation far beyond.
The real question is whether we can expand it to everyone. Unfortunately, there is some reason to think that this may not be possible. If our concept of tribal identity inherently requires both an in-group and an out-group, then we may never be able to include everyone. If we are only unified against an enemy, never simply for our own prosperity, world peace may forever remain a dream.

But I do have a work-around that I think is worth considering. Can we expand our concept of the out-group to include abstract concepts? With phrases like “The War on Poverty” and “The War on Terror”, it would seem in fact that we can. It feels awkward; it is somewhat imprecise—but then, so was the original metaphor of “universal brotherhood”. Our brains are flexible enough that they don’t actually seem to need the enemy to be a person; it can also be an idea. If this is right, then we can actually include everyone in our in-group, as long as we define the right abstract out-group. We can choose enemies like poverty, violence, cruelty, and despair instead of other nations or ethnic groups. If we must continue to fight a battle, let it be a battle against the pitiless indifference of the universe, rather than our fellow human beings.

Of course, the real challenge will be getting people to change their existing tribal identities. In the moment, these identities seem fundamentally intractable. But that can’t really be the case—for these identities have changed over historical time. Once-important categories have disappeared; new ones have arisen in their place. Someone in 4th century Constantinople would find the conflict between Democrats and Republicans as baffling as we would find the conflict between Trinitarians and Arians. The ongoing oppression of Native American people by White people would be unfathomable to someone of the 11th century Onondaga, who could scarcely imagine an enemy more different than the Seneca west of them. Even the conflict between Russia and NATO would probably seem strange to someone living in France in 1943, for whom Germany was the enemy and Russia was at least the enemy of the enemy—and many of those people are still alive.

I don’t know exactly how these tribal identities change (I’m working on it). It clearly isn’t as simple as convincing people with rational arguments. In fact, part of how it seems to work is that someone will shift their identity slowly enough that they can’t perceive the shift themselves. People rarely seem to appreciate, much less admit, how much their own minds have changed over time. So don’t ever expect to change someone’s identity in one sitting. Don’t even expect to do it in one year. But never forget that identities do change, even within an individual’s lifetime.

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