Last week, Tyler Cowen blogged on a story about a special ed program that uses electric shocks to make students to behave. His post included the somewhat cryptic remark that "I view this as a reductio ad absurdum on Bryan Caplan's view that mental illness does not exist."
What is Tyler getting at? As best as I can tell, he is alluding to my argument that if you can change someone's behavior by changing incentives, then he could have done differently all along. And if a person could do X but decides not to, it is silly to blame his decision - however weird - on a "disease." If an alcoholic stops drinking because his wife threatens to leave him, we can infer that heavy drinking was a choice he made, not a disease that happened to him.
So does this article reduce me to absurdity? I don't see why it would. The article shows that you can make the mentally retarded sit still by shocking them when they fail to sit still. Does this "prove" that mental retardation is a choice? Hardly. To do that, you would have to show that shocking them could raise their IQ up to normal levels - which it clearly can't.
So what does the fact that you can make the retarded sit still by threatening to shock them prove? It proves the obvious point that, besides being low in intelligence, the retarded also have unusual preferences. For example, they dislike sitting still more than the average adult does. They also probably prefer cartoons to opera. And if you raise the cost of satisfying their unusual preferences, the mentally retarded change their behavior, just like the rest of us. Big surprise.