Part Primate, Part Pig

In 1976, Richard Dawkins wrote: "Most of what is unusual about man can be summed up in one word: 'culture'."

Genetic differences between humans and chimpanzees would thus likely be explained by a theory of gene-meme coevolution. Or so I have assumed for a decade or so.

Now a rogue scientist has come up with a very different explanation for the differences between humans and chimpanzees. He substitutes "culture" with "pigs".

"Most of what is unusual about man can be summed up in one word: 'pig'. The hypothesis is that a pig and a great ape mated and produced viable offspring. Some of their genes persisted in the population and eventually came to dominate it. Their descendants are modern humans.

This is not a very new idea. Eugene McCarthy as been promoting it for over a decade. For a while. phenotypic similarities were the main evidence. However, now Eugene has performed a genetic analysis that he claims provides solid evidence for the theory. The paper is: "Human Autosomal Nucleotide Positions Differing from Bonobo Instead Match Pig".

It is an amazing, surprising result. If replicated it will likely turn much of our understanding of human evolution on its head. Eugene's data shows that the Y chromosome has a lot of pig influence, while the X chromosome doesn't have any. This implies that the pig males mated with monkey females - and not the other way around. The Y chromosome doesn't cross over, so it means humans basically have a pig's Y chromosome. How come nobody noticed this before? I don't know, but it does look as though the Y chromosome is similar to that of a pig. Various papers have pointed out its oddities.

The pig Y chromosome estimated to be 50Mb here. That is similar to human at 57 Mb. Different from chimpanzee at 25Mb. The conventional explanation is: more sperm competition in chimps generates selection pressure favoring small size. Another site says: ""Puzzlingly, in terms of shared genes and overall architecture, the human Y is more similar to the gorilla Y than to the chimpanzee Y even though human and chimpanzee have a more recent common ancestor."

The evidence from the sex chromosomes is interesting and it could be easy to verify. However the rest of the genome is where the main evidence lies.

Eugene's study needs to be reviewed and replicated - but it is looking as though this could be an important find for those interested in human evolution.

Update: Eugene checked - and the human Y chromosome is more similar to chimpanzee than it is to pig - according to his metrics. It is consistent with the hypothesis of the hybrid inbvolving a male pig - since the pig Y chromosome could still subsequently go extinct in the population.

For more on the gorilla-related evidence see here.

Memetic strategies

Here are a few lists of meme-related strategies. The first list was inspired bt an Alex Mesoudi paper that laid out a fairly conventional view aligned with the work of Boyd and Richerson. Sorry, no link today.

What strategies do people (adopters) use to acquire good memes from others (sources)?

• Are the memes popular?
• Are the memes repeated?
• Do the memes attract attention?
• Do the sources have high-prestige?
• Are the sources related to the adopters genetically - do they share genes with them?
• Are the sources related to the adopters in other ways - do they share memes or environment with them?
• Are the memes likely to benefit the genes of the adopters?
• Are the memes likely to benefit the existing memes of the adopters?

As well as sources resembling them, the adopters can sometimes be interested in whether the sources resemble the adopters in *relevant* ways.

Some of these strategies can be faked or corrupted. For example, high-prestige people could be being paid to appear to associate with the meme, in order to manipulate others into adopting it. This is a common advertising trick. What strategies do memes use to get acquired by others?

• Be memorable
• Be copyable
• Acquire and gain control over resources
• Promise to benefit the host - and deliver on the promise.

To persist in their new host, candidate memes typically have to pass additional hurdles once acquired:

Are the memes compatible with existing attitudes and beliefs?

Are the memes sufficiently memorable?

Prevent rival memes from being adopted

Destroy rival memes already present in the host

Do the memes cause conflict or trouble?

Are the memes useful or helpful?

If memes do not appear to be helpful, might they be so in the future?

Robin Hanson - Beware cultural drift

Robin Hanson has become interested in cultural evolution in 2024. He read Not By Genes Alone, The Secret of our Success, Cognitive Gadgets: The Cultural Evolution of Thinking - and a number of other books on the topic. He has also made some blog posts and videos in the area. Here's a recent video on the topic:

My picture seems significantly different from Robin's. I see meme reproduction at the expense of gene reproduction - likely followed by a machine takeover. I do not forsee innovation grinding to a halt - instead intelligent machines will promote innovation. Robots will become the main consumers. The economy is unlikely to go into decline. The Amish are irrelevant - their rise is too slow to make a difference. We didn't break civilization and civilization is unlikely to collapse. I suspect that the basic problem is that Robin's timelines for the development of machine intelligence are too long.

Rob Boyd & Pete Richerson - Cultural Evolution, Human Brain Increases, AGI, & Fertility Declines

A new Boyd & Richerson interview: