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Worth adding some nuance to the Wrangham framing here — he's not wrong exactly, but de Waal spent decades documenting the flip side: chimps reconcile, console each other, maintain coalitions in ways that don't fit the "demonic males" narrative cleanly. Both are true, and which one you see probably depends a lot on which population you're studying and under what conditions.

Ngogo (which I think this is) is in a fragment under real agricultural pressure. I'd be cautious about drawing evolutionary-psychology conclusions from a group that may be responding to a dramatically compressed territory rather than some baseline ancestral program. Same chimps in intact forest might look quite different.

It seems obvious to me - it's the combination of two ideas:

1. When competing for resources, killing your neighbour frees up resources, which you can take. Most species of animal and even plants do this to some extent.

2. By collaborating in a group, you can achieve more than individuals acting alone. This is the idea behind teams, companies, countries, etc.

Combine the two ideas, and you get war.

Given how easily we can separate people into "ingroups" and "outgroups" and always fall into the same behavioral patterns regarding them, even if the actual markers for the ingroups and outgroups are completely arbitrary, it really seems likely this is biological and not just cultural.

Back in the old days people were much more unabashed about such things. What's the purpose of your very small collection of city states? Obviously to expand, and smash any neighboring states. If you succeed, kill all the men and take their women as slaves. This was much of civilization for a long time.

> primatologist

sometimes I feel like that at work

Don't ant colonies also go to war? I've seen that happen before and it's quite interesting - I read a theory somewhere that part of the purpose of this was to prevent overpopulation, so in the long run _both_ ant colonies do better since they don't "cooperate" and end up overpopulating.

For whatever reason, bonobos living under similar environmental constraints don’t do this. This suggests to me that the behavior is strongly controlled by genetics. Makes one wonder about the warmongers in our own species if they harbor some warmonger gene.

I’m trying to find the source, but I remember a primatologist claiming that humans and chimpanzees are the only two species that embark on genocide. Not being satisfied with simply defeating the enemy, but actively hunting them down to ensure they can’t harm you again. In other words, precluding retreat. (Which creates its own game-theoretical backlash: never retreat.)

> a respiratory epidemic that killed 25 chimps naturally quickly, one would imagine that would have quite a societal destabilizing impact?

there were several seemingly destabilizing factors, sort of a perfect storm, each contributing to further disconnect and polarization.

the group grew too large (and displaced other groups), but then ended competing for the best food among themselves, and having trouble socializing and bonding in such a large group.

subgroups forming, first fluid but eventually creating a split

loss of older alpha males exacerbating competition between males

loss of the few individuals that still maintained some relationship with the other group (the last one doing so actually died in that epidemic while the split was already well underway)

it is indeed an amazing read. my take away is that the root cause was mainly the group becoming too large, this affected socialization and cohesion, and thus the group was unable to cope with everything that came after.

My initial instinct is that they were just reestablishing social order among the group after such a dramatic event.

Edit : I just read the paper and the discussion does a good job at laying out the entire landscape that contributed to the disruption. Pretty fascinating but also totally explainable due to the circumstances explained, which in and of itself is wildly fascinating!

I wonder if chimps are sophisticated enough to believe in omens? Perhaps they saw the sudden deaths are some sort of sign that the established structure was weak or immoral.

We tend to get a lot of things backwards when considering the hows and whys of behavior. The underlying nature is diffuse and chaotic, hard to describe or point at. These superficial differences are built on top of or used to leverage our inclinations and so provide perfect looking reasons.

I'd suggest reading some David Graeber. Viewing everything through the lens of game theory, as if it was some physical law, is very much off the mark.

> We can't overcome the force of game theory

Game theory isn't a force. It's just one way of modeling behavior through one sense of rationality, and it rarely maps neatly onto actual human behavior.

Prime directive doesn't apply because they are part of our home planet. Our actions or in-actions can improve or worsen their living conditions. Their natural world is gone anyway. We've changed it already.

That’s one way to look at it. It’s fairly common to view nature this way. I wonder where it comes from.

I remember the time, in some film I watched, researchers intervened to save penguins trapped in a crater. A holy moment that was.

> To the extent that they have good memory, they live in a world of finite resources, and their behavior was shaped by the forces of game theory as applied to tribes, this is more or less inevitable. You can read that as defeatism or just math. We can't overcome the force of game theory, but we can make it work for us by making our transactions increasingly transparent and repeatable, so that cooperation is more successful than defection.

Note that the conclusions of the paper, while acknowledging the problem of access to resources, are different. They also do not conclude that this is "more or less inevitable":

> The lethal aggression that followed the fission at Ngogo informs models of intergroup conflict. All observed attacks were initiated by the numerically smaller Western group, contradicting simple imbalance-of-power models that predict an advantage for larger groups. Persistent offensive success by Western males suggests that cohesion supported by enduring relationships can outweigh numeric disadvantage. Our observations are also relevant for predictions from parochial altruism. Because cohesion among the Western cluster preceded overt hostility, external threats may be unnecessary to foster cooperation. Cohesion among members of the wider Ngogo group, however, may have weakened when external threats from adjacent groups decreased after territorial expansion in 2009.

and

> This study encourages a reevaluation of current models of human collective violence. If chimpanzee groups can polarize, split, and engage in lethal aggression without human-type cultural markers, then relational dynamics may play a larger causal role in human conflict than often assumed. Cultural traits remain essential for large-scale cooperation, but many conflicts may originate in the breakdown of interpersonal relationships rather than in entrenched ethnic or ideological divisions. It is tempting to attribute polarization and war that occur in humans today to ethnic, religious, or political divisions. Focusing entirely on these cultural factors, however, overlooks social processes that shape human behavior—processes also present in one of our closest animal relatives. In some cases, it may be in the small, daily acts of reconciliation and reunion between individuals that we find opportunities for peace.

Which sounds kinda hopeful!

My own observations is that the preconditions for the split that led to open warfare between the two Chimp groups was:

1. The nonviolent (illness) death of a few key individuals that linked both groups, and...

2. The complete stop of interbreeding. Once the two groups stopped interbreeding, the split was finalized and they became truly hostile.

Stretching this a bit, it makes me think of those (usually white supremacists) who claim "multiculturalism" is to blame for all the world's problems, and if only every ethnic or religious group stayed in their lane and didn't mix with the other, we could all live in peace. But it seems to me the lesson from this paper is that this (isolating us in separate groups) would make the split complete enough that we would decisively start butchering each other.

There's also the 1,5h documentary Rise of the Warrior Apes which is sort of a "prequel" to Chimp Empire. It was filmed over a period of 20 years in the same location and documents how the researches originally came upon this unusual chimpanzee tribe. The production values are not nearly as polished as in Chimp Empire but in my opinion it was still an interesting watch if you find this kind of stuff fascinating. The researchers themselves talk a lot in this.

For those of us who are unlikely to make time to watch a 4-part documentary, are there any particular lessons about social/political dynamics that you learned that stuck out to you or felt particularly prescient?

Loved this series. It was tragic. The cycle of violence, trauma, isolation, male performance.

This is reality TV with animals. Like any reality TV show, the events and reactions are manipulated. I wouldn't put any credibility on this.

No, the outright political warfare in the US you are alluding to began much earlier than 2020. Things were getting quite ulhealthy already back in 2015/2016, probably even earlier. The "black swan" for this deep division was (I believe) not the epidemic, but the proliferation of the smartphone and social media, and the earlier transitioning of traditional news to infotainment format.

I mean, it's understandable; having to endure a lockdown _with_ Doordash was really rough on our civilization.

I am siding with the group that opens bananas from the bottom.

That depends on which side of "our values" you are talking about.

Are you orange team or green team?

negotiations on petrol rights still ongoing.

This got me thinking. Do chimpanzees try and mate with pre pubescent young or is that somehow nature gated?

The Western Ngogo are clearly trying to spread the values of democracy and equality to the backwards Central Ngogo society that also happens to also have resources important to the Western Ngogo

Central Ngogo has complained that every time it's tried to democratically elect a leader, that leader had been overthrown by Western Ngogo—creating an environment that is hostile to anyone other than WN having a so-called "democracy". CN has also criticized WN as ultimately just being "oligarchy with extra steps" and creating an empire that requires the subjugation of CN.

Sandel said he first noticed them polarising in June 2015.

I think the novelty here is that this was the same group which underwent a schism of sorts, and over the course of relatively few years became two completely separate groups antagonistic to each other.

edit: I'm rate-limited, so here's my answer to your comment of:

> I remember watching a nature documentary many years ago with exactly that scenario. The original group killed all the splitters.

Yeah, you're right. You probably remember this: https://en.wikipedia.org/wiki/Gombe_Chimpanzee_War

It does seem like a very similar scenario, so now I'm confused.

It makes sense. Convincing someone to go kill other people so they can take their stuff and rape their women isn't that hard. The personal benefit is front and center, it aligns easily with human nature.

Convincing someone to go kill other people so you can get their stuff is a lot harder. You have to get creative with the reasons, and even then you had better be giving those fighters their cut unless you've really managed to get them fully committed to whatever excuse to made up. It helps a lot if there is some kind of wedge issue you can exploit, which is where religion and ethnicity come in handy.

But... this isn't exactly news, is it?

We've known for decades that chimpanzees go to war, and during that war will happily slaughter each other.

https://en.wikipedia.org/wiki/Gombe_Chimpanzee_War

It's probably all about genes: my genes say I have to kill you now because you aren't spreading my genes. This might be a component of human ethnic violence, but not a strong one, since we can think thoughts, such as that would be a shitty thing to do.

yeah but some people still think "imagine" is profound and real

> That's a weird thing to say. Studies of primitive tribes showed decades ago that they only seem to fight each other for a handful of reasons. Religion, ethnicity and political beliefs aren't among them. Fighting over resources, women and blood feuds are.

Why is it weird? Religion, ethnicity and political beliefs are argued all the time, even here on HN, as the reason for why shit happens.

Also, what is a "blood feud" in the primates? Chimps seeking revenge for the murder of another Chimp? Why was the first Chimp killed then? I think "blood feud" is a good start, but why? The paper sort of explores possible reasons.

> Supposedly academic anthropology had difficulties accepting these findings, especially the Yamomamö studies by Chagnon where he documented them going to war to steal each other's women, as it contradicted the popular idea of the noble savage.

I don't know what you mean, the "noble savage" is a discredited racist trope. Chagnon is worth considering but surely you're aware of the academic criticism of his work and methods? It wasn't because of the "noble savage", that would be a lazy dismissal of the criticism. He didn't have the final word on the topic.

No religion other than Christianity and Islam fought for a man made religion. They haven't slowed down after wiping out thousands of cultures and tribes

Google tried, but no apes were impressed with nano-scale bananas.

Agreed. I came to the conclusion years ago that we are going to keep having the same problems until we engineer our way out of them by altering our biology-- either genetically or with implanted augmentation devices (or both).

I have yet to see a convincing counter argument to this hypothesis.

We both do it because chimps and humans shared a common ancestor only 8 million years ago.

That's a bit conceited.

Animals have inner lives as well. They have their own thoughts and feelings. And sometimes those feelings are anger and their thought is to kick the shit out of those assholes over there.

Fuck man, my cats occasionally scrap with each other. I know it's not anything they've learned from the people in my house because we don't go full Wrestlemania on each other.