It has been argued previously here that John McCain, among others, seems to harbor a pronounced dislike for economists.
Well, you don’t even have to be a politician to hate economists. Via Cory Doctorow at BoingBoing, here’s a fascinating bit from an old paper by Robert Frank, Tom Gilovich (best known for his hot-hand refutation, and this fun book), and Dennis Regan that assesses how economics students perform in cooperation games as compared to other people. It’s not pretty:
A study by Gerald Marwell and Ruth Ames found that students of economics are indeed much more likely to free-ride in experiments that called for private contributions to public goods.
Their basic experiment involved a group of subjects who were given an initial endowment of money, which they were to allocate between two accounts — one “public,” the other “private.” Money deposited in a subject’s private account was returned dollar for dollar to the subject at the end of the experiment. Money deposited in the public account was first pooled, then multiplied by some factor greater than one, and then distributed equally among all subjects.
Under these circumstances, the socially optimal behavior is for each subject to put her entire endowment in the public account. But the individually most advantageous strategy is to put all of it in the private account. The self-interest model predicts that all subjects will follow the latter strategy. Most don’t. Across 11 replications of the experiment, the average contribution to the public account was approximately 49 percent.
It was only in a 12th replication with first-year graduate students in economics as subjects that Marwell and Ames obtained results more nearly consistent with the self-interest model. These subjects contributed an average of only 20 percent of their initial endowments to the public account, a figure significantly less than the corresponding figure for noneconomists.
Among other things, this might explain why:
1. Economists carry a more dyspeptic view of human behavior than nearly anyone else; and
2. Why comments on economics blogs (though not this blog, which is more econ mutt than purebred) tend to be more cutting than average, by a factor of about 8,000.
3. Behavioral lab studies in general should be reviewed skeptically, for the deck can be stacked in oh-so-many ways.
(Hat tip: Therese Odell, and a few others.)
and 
. You can also watch it on 
I’m sure glad you brought up John McCain again at the top of this story. It was a vital piece of information necessary to the comprehension of this story.
Were there specific issues to be skeptical of in this study, with regards to the deck being stacked against economic students or in favor of non-economic students? Or was that more of a general warning? It would seem disingenuous to suggest there is or may be bias without direct evidence of any.
But it’s not even a prisoner’s dilemma scenario. If everyone puts in 100%, everyone gets more. Granted, you can screw people over by putting in less, but it’s hard to see the appeal of that over free money.
I think that you are right about the lab results, especially regarding the pd game.
Most pd games have either subtle clues about what the experimenter sees the point of the game to be, in the labeling of the strategy choices, which non economists might use to coordinate expectations.
(It has only been recently that experiments have even started using and controlling for different labels.)
People exposed to the nash reasoning might use it to coordinate expectations, instead.
In neither case, should make conclusions about self interest. We would have to know much more than we can get out of the lab pd game.
Hmm. Now let’s correlate that 20% figure with the graph I saw a couple of months ago that tax revenues to the Federal government always seems to be around 20% of GDP regardless of the marginal rates. Coincidence? Or a universal “sharing” constant hard-wired into the human brain with civilization-shattering implications? Let’s post some cutting comments about it.
“Why comments on economics blogs (though not this blog, which is more econ mutt than purebred) tend to be more cutting than average, by a factor of about 8,000.”
What does “more cutting” mean? How something judged more so by a factor of 8000?
I think you could substitute Libertarian for economist and get the same result.
blackpoliticalanalysis.com
Yeah… or 1st year Econ grad students more often had game theory in their undergrad coursework than, say english majors.