Tuesday, December 22, 2009

Status and Evolutionary Biology

Economists tend to judge in absolute terms. If my real income doubles that's a big win for me—even if yours triples. We find it odd and annoying that other people often prefer to look at relative measures. If the income of poor people doubles and the income of rich people triples, many will see that as the poor losing out, or at least falling behind. In Choosing the Right Pond Robert Frank, an original and interesting economist, explored the implication for economics of the fact that people care about relative as well as absolute outcomes. That fact suggests an obvious question: Why do we care about relative outcomes? To explain why humans are as they are, the obvious tool is evolutionary biology.

Humans, like other living creatures, are "as if designed" for reproductive success. Reproduction requires two sorts of inputs—resources and a mate. If you are a better hunter than I am you will get more resources than I will, making you better able to feed your offspring. But that doesn't make me any less able to feed mine. From our standpoint as members of a hunter/gatherer tribe, the environment in which humans spent almost all of their evolutionary history, game is out there to be hunted in effectively unlimited supply.

If you are a better hunter than I am, more generally if you have more resources, status, whatever matters in our society than I do, you will also be better able to attract a mate. Mates, unlike game, are in strictly limited—for practical purposes, perfectly inelastic—supply. The better you are at attracting one or more, the worse my chances of doing so are. That is a good reason for me to be concerned about relative as well as absolute results, to wish not only that I should succeed in the hunt but that you should fail. It might even be a reason for me to put some efforts into increasing the chance of your failing if suitable opportunities arise.

The late George Stigler taught me an important lesson when he rejected the original version of what was to become my first published journal article in economics. He told me that in order to be publishable, the article required not only a theory—in my case of the size and shape of nations—but also some way of testing that theory. In revising to meet that requirement I not only found evidence in support of my theory, I also, and perhaps more important, was forced to think through more carefully and precisely what the theory said.

I have done no testing of my theory of why we care about relative status, but I do have predictions. The first is that males should be mainly concerned about their status vis a vis other males, females about theirs vis a vis other females, since males are competing with males for mates, females with females.

The second is that males should be more concerned with relative outcomes than females. Reproductively speaking, wombs are a scarce resource, sperm is not. Even a not very successful female can expect to reproduce, although her success in mate search may determine how much help she gets raising her children. An unsuccessful male is likely to have no children at all, a successful one many. From the standpoint of reproduction, being male is a high risk gamble.

The third prediction is that people should be most concerned about relative outcomes in a range near their own level. If Bill Gates increases his wealth from twenty billion dollars to thirty billion, that has no effect on his ability to compete with me for mates; insofar as wealth is the relevant criterion, at twenty billion I've already lost, although that would be less true in a polygynous society, where his extra wealth might result in his bidding a few more potential wives away from me. If a homeless man finds a job at MacDonalds, that has no effect on his ability to compete with me for mates either. The people I ought to worry about—supposing that I am a male in the mate market, as most males were for most of their adult lives in the environment where we evolved—are the men at about my level, the ones who might beat me out in courtship if they were a little richer, or a little handsomer, or ... .

This is a blog post not a journal article; I haven't actually done the research to test these predictions, although I wouldn't be surprised if someone else has. If any readers know of such ... .

(It has been many years since I read Robert Frank's book and I don't have a copy ready at hand to check; it's possible that he came up with some or all of my explanation first.)

13 comments:

RKN said...

Testing each of the three predictions would require devising a quantitative measure of "concern", something that I expect would have a very large variance and be laden with assumptions.

In terms of modeling, I might turn to the field of human psychology rather than evo-bio, as a number of the underlying assumptions of the latter either no longer apply to modern humans or are practically irrelevant, with respect to the concerns you describe.

Phil Birnbaum said...

But if that's the case, why would anyone care that the poor are "falling behind?" People would WANT other people to "fall behind".

As you point out, if I'm making $30K a year, I won't care if people making $100K a year last decade are making $150K this decade. But they do. They talk a lot about the top 1%.

Anonymous said...

But if that's the case, why would anyone care that the poor are "falling behind?" People would WANT other people to "fall behind".

Sure, if people were simple and had only one impulse on any given subject. In reality, people have a drive to compete, and a drive for justice and fairness, and a drive for compassion and empathy, and a drive for greed and consumption,, and a drive for group altruism... most of which the evo-bio people have explanations for. In reality, people apply all of these conflicting drives in deciding what to do in a particular situation.

Peter A. Taylor said...

Bottom of p. 19: "Several reasons suggest that natural selection should have similarly favored those who were driven to seek high rank.... In general, whatever steps we take to move as far forward as possible in our social hierarchy will improve our access to a variety of other important resources that are in more or less fixed supply. Our changes or ending up with a desirable job, a sought-after mate, and other resources needed to raise large families are all enhanced by having high rank in our social hierarchy."

Peter A. Taylor said...

Oops. "changes or" should be "chances of".

Patri Friedman said...

I was just reading about some evidence like this. Male testosterone levels change in response to success or failure in tournaments, but female do not. And not just tournaments - also presidential elections, providing some support for the claim that our intuitive view of politics is based on tribal status competitions.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2760760/

Anonymous said...

I don't know how much mate selection can be based on material resources alone in the Evolutionary Biology of humans. For most of history, humans lived in groups of 30 to 100 based on natural resources density. There is no reason why each member in the group would be completely self sufficient. Some members could be better at fire, others spear points, others spear shafts, others tracking and killing, other at clothing, others at shelter, etc. This interdependence could have reduced the importance of material resources to females. Either the group had what it needed to survive or didn't. It's possible that females would look for males that focused their attention on others hoping that they would become helpful fathers in the future.

Jonathan said...

An interesting point, thanks. But I think finding a mate is not the only thing to consider. People naturally define normality by what they see around them. If I'm doing better but other people are doing much better, I look around me and wonder why I'm falling behind. Conversely, if I'm on half pay while everyone else is unemployed, I suppose I must be doing something right.

It's a way of evaluating your own strategy in playing the game of life.

Anonymous said...

you will get more resources than I will, making you better able to feed your offspring. But that doesn't make me any less able to feed mine
Since all tangible resources by definition are scarce, is that statement true? Won't your acquisition of resources somehow limit or complicate my acquisition of that resource?

Unknown said...

Phil makes a good point.
In Australia, where I'm from their has been a bit of talk about legally capping CEO's salaries. Most people arguing for it earn nothing near what the CEOs are earning. Not only that, most of the CEOs that would be capped are men. The proponents of the cap seem to be to be more or less women and men in equal amounts.

Evolution and survival of the fittest can probably explain how hunter gatherer societies work, but be careful when applying the same rules to the modern society which is overwhelmingly more complex.

Here's Noam Chomsky and an evolutionary biologist discussing how evolved self deception led George W to invade Iraq. Likening him to a gorilla banging his chest to intimidate a competing male. Applying natural selection to an extremely complex geopolitical situation and everything else is probably simplifying it a bit don't you think?

http://www.channels.com/episodes/show/123393/Seed-Salon-Noam-Chomsky-Robert-Trivers

A Life Long Scholar said...

I strongly disagree with the statement "The better you are at attracting one or more, the worse my chances of doing so are." Evolutionarily speaking, there is no reason for mates to be limited to one other partner. Every individual is free to mate with as many other individuals as they desire/are able to attract. While many human societies have chosen to add social pressures designed to limit the number of mates which are available, such limitations are naught but a social construct, and many humans choose to disregard them. (Some "ethically" by making certain that all of their mates are aware that they have more than one mate, others "unethically" by lying to each of their mates about their status.)

David Friedman said...

A Lifelong Scholar writes:

"Evolutionarily speaking, there is no reason for mates to be limited to one other partner. Every individual is free to mate with as many other individuals as they desire/are able to attract."

That might be true if we were talking about recreational sex, but "evolutionarily speaking" what matters is reproductive sex, and that is indeed limited to one partner at a time. If a woman is currently pregnant with your child she isn't pregnant with mine.

RKN said...

David Friedman comments:

That might be true if we were talking about recreational sex, but "evolutionarily speaking" what matters is reproductive sex, and that is indeed limited to one partner at a time. If a woman is currently pregnant with your child she isn't pregnant with mine.

She certainly could be. Dual paternity is rare in humans, but not biologically impossible. And indeed it's been observed in other species whose members only engage in reproductive sex.