Crime and Rationality

There was an article on "neurolaw" in the March 11 Sunday New York Times magazine. Nerolaw studies brain patterns to learn more about crime. One of the experts they quoted "wrote a widely circulated affidavit arguing that adolescents are not as capable of controlling their impulses as adults because the development of neurons in the prefrontal cortex isn’t complete until the early 20s."

This reminds me of something at the bottom of page 152 in the book The Economics of Public Issues. It discusses work by Steven Levitt on crime and mention that teenagers respond to incentives.

"In states tough on youth but easy on adults, violent crime rates rise 23% at age 18, but in states that are easy on juveniles and tough on adults such crime drops 4% at age 18."

I don't know if this accurately portrays Levitt's research, but it shows the opposite of what the expert said might be true. Teenagers might be able to control their impulses. In fact, economists have found that even people in mental hospitals can act rationally. For example, if doctors paid agoraphobics tokens to walk outside, very often they did (tokens that could be used to buy things in the hospital store). Patients also got paid for doing jobs or performing tasks. If no one would mop the floor, the pay for mopping the floor was raised and several patients came forward to do the mopping. That is completely consistent with economic theory. Offer a higher pay, more people will do the job (law of supply).

They aslo changed the prices of items in the store. If the price of an item was dropped, the amount purchased went up (and vice-versa). This means that even patients in mental hospitals follow the law of demand. When patients got paid for doing jobs, they did them. But when the hospital tried to get them to do the jobs without pay, the patients stopped working. In another case, if their pay in one job was taken away, they took a job that they liked less if the pay was still there.

The discussion of patients in mental hospitals comes from the book The Best of the New Worlds of Economics.