Scalability, Communism and Dunbar Number

In his book, Filters Against Folly, Garrett Hardin cites a very interesting reason as to why communism doesn’t work. The one line summary: communism doesn’t scale up. Huh? What is scalability? Scalability refers to a system’s ability to work the same way as it gets bigger and bigger. Engineers and scientists know that most systems do not scale up: this is why a mouse cannot be the size of an elephant. Mathematically, it’s because:

“The weight of an animal goes up as the cube of its linear dimensions, whereas the strength of its supporting limbs goes up only as the square.”

Ok, but what’s the connection to communism? Let Shane Parrish summarize the scalability argument:

“The reason communism or utopianism can work at small scale is because of the tight knit nature of a small group…(but) The problem is that the system of communist distribution which worked for a tight-knit group of 4 people did not scale to 400. Each person, less visible to the group and less caring about others they rarely interacted with, decided in turn to cheat the system just a bit, and only when “needed.” Their cheating had a small individual effect initially, so it went unnoticed. But the follow-on effect to individual cheating is group cheating, and the utopian goal of To each according to his need, from each according to his ability had the effect of expanding everyone’s needs and shrinking their ability, aided by envy and reciprocation effects. Human nature at work.”

This would imply that people would work as a group selflessly upto a certain size, but not beyond that. Mostly because beyond a point, people don’t know everyone else; and cheating a little against people one barely knows is a lot easier than cheating someone they know well. So is there a maximum group size until which people can know everyone else?

Yes, there is: the Dunbar number! In his terrific book, Writing on the Wall, Tom Standage gave a great description of the Dunbar number. Take the ratio of the neocortex (a part of the brain) to the total size of the brain. Next, plot that ratio against the average group size that the animal lives in. It turned out that this ratio to average group size is close to a constant (among primates)! Given that we humans are primates, Dunbar calculated the group size for us given our neocortex ratio. The answer? 150.

But how do you check that? Facebook, of course! And it turns out this is pretty close to the friend count for most people. (Semi-)Jokes aside, the 150 number is close to the group size of many communities living far from civilization; so this would seem to be a fair estimate.

Does all this prove that the “To each according to his need, from each according to his ability” Marxist principle can only work for groups smaller than 150?