This essay is about human culture and its relation to evolution. Some use culture to encompass useful information and skills that is passed down by education or imitation rather than by any biological mechanism. So, we see headlines like "Crows shown to have culture". Humans have always had this sort of culture since it already existed in.prehuman species. However here I use culture to refer to things which are arbitrary but learnt, like language, and which thus differ between groups. Indeed I'll argue that distinguishing groups is their evolutionary purpose. This form of culture arose relatively recently, perhaps 100,000 years ago, and 30,000 years ago it swept aside remaining precultural groups to become a universal and crucial aspect of human nature.
Culture is the jewel in the crown of human nature. We like to form groups based on aspects of culture: "We are the people who speak this language (with its tricky corner cases)"; "We are the people who dress like this, and wear our hair like this"; "We are the people who believe X, where X is based on faith not evidence, and perhaps explicitly disagrees with a neighbouring group's belief"; "We are the people who do this sort of cooking or pottery or art or music or dance or architecture or sport".
We are going to ask the question: "What, in evolutionary terms, is culture for?". But first we need a detour on cooperation.
Humans cooperate. This is clearly beneficial, and indeed essential. So, you wouldn't think it would need an explanation. But it does.
The problem with a species that cooperates is that a mutant individual who doesn't cooperate has a huge advantage. They get the same benefit from other co-operators, but they have extra resources to devote to their offspring because they aren't doing their share of providing resources to others.
The most plausible route to cooperation is within a group of closely related individuals. That is how bees and ants do it. In "The World Until Yesterday", Jared Diamond describes the villages as being substantially inbred, but with some outbreeding.
Andrew Bourke wrote in Nature News and Views on 2021-02-01: "in the early 1960s, the evolutionary biologist W. D. Hamilton came up with a solution to this ‘problem of altruism’ with his inclusive fitness theory, which shows that it is possible for altruism to evolve if socially interacting individuals are related. Writing in Proceedings of the National Academy of Sciences, Kay et al. conclude that multiple attempts to find alternatives to Hamilton’s solution have simply rediscovered it."
Before culture, humans were all in groups where everyone knew each other. To make cooperation work they must have been inbred. That gives our genes the incentive to cooperation, because the individuals we help have the same genes. The evolutionary change to promote cooperation occurs because of competition between these groups.
This is good, but not enough. To keep cheaters from taking over requires genes for relentless opposition to cheating. And so it is that we hate cheaters who don't pull their weight.
We admire the individuals who take risks and pay personal costs to stand up against criminals and other less extreme cheating. The key observation is that this courageous behaviour only exists because the benefit to the individual's genes outweighs the immediate cost from the inevitable risks of conflict. This works in an inbred group because it benefits other individuals with the same genes by benefitting the group as a whole.
Groups are in eternal conflict with neighbouring groups. This is how it is with our close relatives, the chimpanzees, and also with villages in "The World Until Yesterday". Groups that don't control non-co-operators will lose and be wiped out. Successful groups can expand and split when they get too big. We also presume that groups which are too inbred will lose, so there is a balancing act on bringing in, or just mating with, outsiders.
That was the human world before culture. Then evolution took an interesting turn, starting with the invention of culture.
It is not by chance that our cultures take years to learn proficiently. Languages, for example, are filled with special cases and tricky idioms. The effect of this is that someone who wasn't raised in the culture can't come in and pretend to be from it.
Before culture, groups were limited to the number of people who could all know and recognise each other. Culture allows us to build bigger groups. So, we love to form groups based on various aspects of culture, particularly language. The genes for culture spread because the larger culture-based groups were able to beat the smaller traditional groups. I used to think that this was about violent conflict, but I am convinced by Adam Rutherford's Darwin College Lecture, https://youtu.be/Me5LFbPrEe0, that what it was about was establishing the communication and trust that enabled more complex technology to be used and passed from generation to generation.
We love culture, but there's a problem:
When we stand up to criminals and other non-co-operators, we take a risk. That risk has to have a payoff -- not to us personally but to our genes. That worked when we were in small, inbred groups where our shared genes would lose out if we didn't maintain cooperative behaviour.
There's still a big payoff from opposing non-co-operators. The trouble, from an evolutionary point of view, is that the payoff goes to everyone, but the cost goes to the courageous individual. Those good guy genes are going to lose the battle, opening the floodgates for cheating to destroy cooperation.
Yes, I am saying that evolution has made a change which has been initially enormously successful, but which will, if left to its own devices, eventually destroy our species.
It is natural to personify genes because they seem to act purposefully. That's what Richard Dawkins did when he named his famous book "The Selfish Gene".
Our genes don't care about the individual or about the species. They care about themselves. But they are stupid and can make big mistakes.
"Empire of the Ants" is a documentary by David Attenborough. It shows two similar species of ants. In one of these the different colonies, each with one queen, fight each other to maintain and extend their territory. The other species have discovered cooperation. Ants from the megacolony help each other and don't fight. Attenborough suggested that ants have only recently discovered cooperation. But probably the real story is that ants have invented cooperation many times, and for a long time it is beneficial. But eventually cheaters take over, the failed co-operators lose out to fighters, and the cycle starts again.
If we understand the problem outlined here then we have some chance to avoid the consequences.
