Slashdot Mirror
Crime Reduction Linked To Lead-Free Gasoline
Hugh Pickens writes "Even low levels of lead can cause brain damage, increasing the likelihood of behavioral and cognitive traits such as impulsivity, aggressiveness, and low IQ that are strongly linked with criminal behavior. The NYTimes has a story on how the phasing out of leaded gasoline starting with the Clean Air Act in 1973 may have led to a 56% drop in violent crime in the US in the 1990s. An economics professor at Amherst College, Jessica Wolpaw Reyes, discovered the connection and wrote a paper comparing the reduction of lead from gasoline between states (PDF) and the reduction of violent crime. She constructed a table linking crime rates in every state to childhood lead exposure in that state 20 or 30 years earlier. If lead poisoning is a factor in the development of criminal behavior, then countries that didn't switch to unleaded fuel until the 1980s, like Britain and Australia, should soon see a dip in crime as the last lead-damaged children outgrow their most violent years."
Levitt's book is cited in the first paragraph of the paper, which is very interesting, but rather hard to understand on a (very) brief reading. Essentially, she says that lead contributes 56% to the drop in crime, while the availability of abortions contributes 29%.
Reality is defined by the maddest person in the room
"Lead has also been associated directly with delinquent, criminal, and aggressive behavior. Denno [1990] finds that lead poisoning is the most significant predictor of disciplinary problems and one of the most significant predictors of delinquency, adult criminality, and the number and severity of offenses. Needleman et al. [1996] find a significant relationship between the amount of lead in bone (a good measure of past exposure) and antisocial, delinquent, and aggressive behaviors. Dietrich et al. [2001] followed a cohort of 195 inner-city youths from birth through adolescence, and found a clear linear relationship between childhood blood lead levels and the number of delinquent acts. In addition, Needleman et al [2002] showed that adjudicated delinquents were four times as likely to have high lead levels than non-delinquents, and several studies have shown that violent criminals exhibit higher levels of lead in their bodies than nonviolent criminals or the general population.25"
It seems to me that this environmental hypothesis is testable (and confirmed) far beyond what is attainable for most theories in the social sciences.
These statistical correlations are a complete crock. There are a million things that have changed over the last few years that could also be attributed.
One that was done piecemeal (so regression analysis could be performed) and which produced a strong signal under such analysis: Allowing law-abiding citizens to carry concealed weapons for self-protection against criminals. This drastically lowers the overall violent crime and injury/death rates (even if you DO count any crooks shot in self-defense as a "victim").
Interestingly, while many thought it might produce a short bloodbath (until criminals got the message that some of their victims might be armed), that didn't happen. Instead the violent crime rate just dropped, as criminals moved to less-armed areas, switched from muggings, armed robberies, carjackings, "hot" (occupied-dwelling) burglaries, to things like burglarizing UNoccupied homes and stores, or just found legal work. Rapes dropped like a rock, too (though they went up somewhat in nearby areas that hadn't yet liberalized their own laws.)
Turns out the crooks weren't SO stupid that they couldn't see the writing on that wall. And even those who didn't get the message right away usually weren't dumb enough to keep attacking, rather than run away, when they found themselves looking at the wrong end of a pistol.
(When Florida changed to non-discretionary CCW (i.e. the license has to be granted if the applicant jumps through the correct hoops and doesn't have a criminal record), one gang switched to hitting tourist in rental cars, on the assumption they'd be unarmed - both by airport regs and lack of a permit. Florida fixed that by removing the requirement that rental cars have distinctive markings/licenses and by issuing concealed carry permits to tourists. B-) Interestingly, even during the peak of the rob-the-Florida-tourists boom a tourist had less chance of being robbed in Florida than in California.)
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way