Inequality

We have some techniques for measuring the degree of inequality. For example, use of the Gini coefficient is becoming quite widespread. This is useful for thinking about whether the distribution of something is more unequal or less unequal than some other distribution. It isn’t perfect, but it’s a start.

Unfortunately, our mental heuristics† for assessing inequality have not caught up. On the face of it, equality corresponds to a single value of the Gini coefficient, zero, while inequality applies to all other values greater than zero and less than or equal to one (the coefficient is defined over 0 to 1). The thing is, these are point estimates. So, the probability of any distribution’s Gini coefficient hitting any value exactly is … zero. In some sense, we’re never likely to find equality (which is a fairly useful property if you like to complain about the pervasiveness of inequality).

In economic situations the typical heuristic is that the world we observe is too unequal because there are monetary/political/legal/social/cultural forces that have pushed us away from equality, and are capable of sustaining distance between how unequal things are and how equal we’d like them to be.

Now, let me modify that third paragraph with the implication of the second paragraph to get:

In economic situations a more realistic heuristic is that the world we observe is too unequal because there are monetary/political/social/cultural forces that have pushed us away from some more natural level of inequality, and are capable of sustaining distance between how unequal things are and how unequal we can reasonable expect them to be. [I’ve emphasized the modifications between the two paragraphs].

My point in this is that we can still be concerned about inequality while we go and explore the world for how much inequality is actually OK. That’s a premise that lots of people haven’t really considered, but it’s essential for things like, say music, where the inequality of tastes is what makes it worthwhile.

So, where to start? How about with “A Comparison of Wealth Inequality In Humans and Non-Humans”. The paper is behind a paywall, but this is excerpted from the abstract:

In many societies, the statistical distribution of wealth takes a characteristic form: unimodal, skewed to the right, and fat-tailed. …  we present the first description of inequality in material resources in an animal population … the shell distribution for the [hermit] crabs strongly resembles the characteristic form of wealth distribution in human groups. The amount of inequality in the crabs is more than that in some small-scale human groups but less than that in nations. We argue that the shell distribution in the crabs is not simply generated by biological factors such as survival and growth of either crabs or gastropods. Instead, the strong resemblance in the human and hermit crab distributions suggests that comparable factors, not dependent upon culture or social institutions, could shape the patterns of inequality in both groups. …  We also propose that inequality in hermit crabs could provide a baseline for examining human inequality.

For those of you that don’t know, hermit crab exoskeletons are not very serious defensive shells, so they move into harder shells of other creatures that have died. The crabs ability to grow is based on finding a shell that is big enough for them to grow into, but small enough for them to still maneuver. Since mollusks do not stop growing as they age, a hermit crab may go through several shells in its lifetime. Basically, their success as individuals is based on finding natural resources and using them in a rivalrous and excludable manner. And they result is inequality.

Sounds a lot like humans … except that there aren’t monetary/political/legal/social/cultural forces making it happen. This suggests that equality is not the null hypothesis we should be using for assessing human affairs.‡

† Heuristic is a good college level word that you should look up.

‡ Kurt Vonnegut’s short story “Harrison Bergeron” is a satirical look at what might happen if we did.