10 May 2022. Dunbar | Wealth
Why talking is more efficient than picking fleas out of fur.// How Elon Musk paid for Twitter.
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It’s a slightly lightweight Just Two Things today—I was a bit distracted when I was supposed to be writing it.
1: Why talking is more efficient than picking fleas out of fur
The Dunbar number is a pretty familiar thing. It says that 150 is the natural size of human groups, and Dunbar hypothesised that this might be the case in 1993.
A recent blog post by the software developer Matt Webb re-reads the paper goes into some of the theory that sits behind the number. (He also posts a pre-print of the original article).
The number itself is seen in all sorts of social organisations in different cultures and periods of history, from Mesopotamian villages to American Hutterite communities, to the basic organisational unit of the Roman army—and many others since. When AOL (the early internet service provider) was set up, 150 was the limit on the number of buddies you could have. So on the face of it there’s something to explain here.
(Bonnet macaque monkeys grooming. Photo by ‘AKS 9955’, via Wikimedia. CC BY-SA 4.0)
Dunbar started by looking at the behaviour of ‘catarrhine primates’—“Old World monkeys (baboons, macaques, mandrill, and 130 other species) plus the apes… tailless simians including gibbons, gorillas, chimpanzees, and humans", and realised that their social behaviour could be explained by the interaction of three things:
- Group size
- Time devoted to social grooming: a bonding mechanism (if you wanna have friends, you gotta spend time picking fleas)
- Neocortex size, being the amount of brain available for tracking the social group.
So he relates these three numbers via an equation, starting with non-human primates, and finds that the predicted size of a human social group would be 147.8. (Chimpanzee social groups are smaller, at closer to 50).
However, there’s a catch. That group size would require humans to spend 42% of their time on social grooming. In practice, it’s more like 15%.
Humans, says Dunbar, must have a method of social grooming that is 2.8x more effective than the method used by the nonhuman primates. But what is it? What is our ultra efficient bonding mechanism, better than caring, grooming, and picking fleas? It is LANGUAGE.
And one of the reasons why speaking is better than grooming is that picking fleas can only be done one-to-one, whereas language can involve several people. And that producers another hypothesis:
The interesting bit, for me, is about the “natural” size of a conversation group. Dunbar’s prediction, based on the estimated efficiency gain versus chimps: human conversation group sizes should be limited to about 3.8 in size (one speaker plus 2.8 listeners). And this holds up!
Restaurant bookings, for example, average out at 3.8: speaker plus 2.8 listeners.
And there’s more here—the reason it’s 2.8 is because of cognitive limits on listening—the distance at which speech becomes hard to hear. This extract is from Dunbar’s paper:
It turns out that there is, in fact, a psycho-physical limit on the size of conversation groups. Due to the rate at which speech attenuates with the distance between speaker and hearer under normal ambient noise levels, there is a physical limit on the number of individuals that can effectively take part in a conversation.
And obviously we don’t have 150 close friends. The 150 is made up of a series of layers (this extract is a summary that Matt Webb found in the MIT Technology Review:
Individuals, he says, generally have up to five people in the closest layer. The next closest layer contains an additional 10, the one beyond that an extra 35, and the final group another 100. So cumulatively, the layers contain five, 15, 50, and 150 people.
And it turns out that some research on actual human behaviour has borne this out as well. Researchers analysed 6 billion mobile calls made by 35 million people, and:
the average cumulative layer turns out to hold 4.1, 11.0, 29.8, and 128.9 users.
2: Now you see it, now you don’t: how Elon Musk paid for Twitter
Regular readers will know that I’m interested in the way that our financial and economic system is skewed for the benefit of the very rich, of the people who own the capital. It’s often quite hard to explain how this works, certainly not in everyday language, which, of course, is just fine as far as the very rich are concerned.
So kudos to Trevor Noah, the presented of the American show The Daily Show, for explaining the way that Elon Musk is able to finance his purchase of Twitter.
The clip’s only four minutes, but the ‘don’t have time to watch’ version goes like this:
Musk isn’t taxed on his Tesla shares, because he hasn’t realised the gain yet (in tax language, they need to be ‘crystallised’ to become taxable, by selling them.
But even though they’re not visible for tax purposes, they are visible for the purposes of buying Twitter, because he can use them as a security to borrow the money to buy Twitter.
Noah doesn’t use the phrase, but this is having your cake and eating it. And of course, those of us who merely earn wages and salaries don’t have this benefit.
j2t#312
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