Even assuming a lag time of 20 years, how come the rates spiked in '90 to '95? Leaded gas had been around since 1920. On top of that, why did all age groups spike simultaneously? I would expect lead poisoning to basically accumulate until a standard tipping point; in the given theory: 19 years. You would have to try to find some explanation about the amazing lead resistance of earlier generations. And, that all wore off at the same time.
Another problem is that I would expect lead poisoning effects to linger. I would expect to see a tailing effect in the statistics, which is most prominently not the case.
Anyone looking for an explanation should not start by looking at why the crime rate dipped, but why it spiked. What kicked in around '88?
Or what the heck: what kicked in around '68-'69? Maybe chemicals are at fault, but I’m starting to think it might not be lead…
In fact, the crime rate started to rise in the late 1950’s, I think. Also, I wonder if we simply don’t have accurate crime rates from early years. I suspect that many crimes were simply never reported or were ignored by the police even if reported. They just considered that “those ignorant lower-class slime” were always robbing and killing each other and there was no point in making note of most of it.
We can’t * just* look at homicide, as increases in the success of medical intervention have resulted in stabbings and shootings being more survivable. Article in Saturday’s WSJ on this. Or maybe kids these days are just lousy shots.
You will be shocked to learn scientists are in fact familiar with the difficulty of showing causation rather than just correlation.
The article in the OP has links to some papers that use various techniques to suggest that the reduction in environmental lead is the cause of crime reduction.
I have to go on the record here and say I’m not convinced. It’s a lot like global warming: we have a trend; we have another trend; now let’s see if we can make them fit nicely together.
There’s more than just a single trend though. Crime rates fell in sync with differing national, regional and local timelines for phasing out leaded gas. That’s much more difficult for me to dismiss as simply coincidence.
The other compelling item was that during the time of lead use, violent crime per capita was higher in urban areas than in rural areas, urban areas being more lead contaminated. After the phase out of lead, per capita violent crime dropped in urban areas to more or less the same level of the in contaminated rural areas.
Australia banned leaded gas 10 years later than North America. There are other countries that didn’t follow in synchronization either. Show me some graphs from those countries that also follow along, and that aren’t attributable to other variants, such as demographics or increased police presence, or better first responder times, etc.
The science is a little dense for me, but it looks like that information is in the source paper, graphs and all, here, pages 319 to 324.
Again, I quote the MJ article…
Indeed, it seems to be very possible that it’s a spurious correlation in any one given region, but since the paper shows that same correlation in seven different countries with seven different lead phase out timelines, well, it seems much less likely that something like police presence would so similarly align with the lead timing in each individual case. And if I understand what I’ve read correctly, that correlation even applies within the US, based on different phase out schedules in different regions.
Add to that that modern day crime rates seem to correlate well with regional lead contamination down to the neighborhood level, well, it looks pretty damning to me.
I don’t see why the conclusions are so astonishing. Given that we know independently that lead preferentially damages structures of the brain responsible for executive functions, it’s not hard to draw the connection to young adults with, shall we say, poor impulse control among other things, no?
If you used to live in a leaded smog-filled hell hole maybe. I’ve never lived in a smog-filled hell hole and crime rates have dropped similarly. The air in a lot of Canadian cities, and especially rural places where crime has also dropped has never been an issue. It looks like a very specious theory to me.
I don’t think anyone’s posited that you had to have lived in a smog-filled hellhole to have been exposed to too much lead in the 50s-70s. Blood test levels of children everywhere were too high in that era. It doesn’t take much exposure, and unless one lived a Grizzly Adams lifestyle, there was plenty of opportunity to be exposed to automobile exhaust at unhealthy levels.
And, as the article and paper both point out, violent crime has dropped much, much less in rural areas as compared to urban areas. The trend has been for urban crime rates to drop to parity with rural crime rates, not for both to sink in parallel.
It’s not just trend-fishing. In both cases, very basic science tells us that changes in one variable should lead to changes in another. Just like we know that CO[sub]2[/sub] has a warming effect (we’d be dead on an icy snowball earth if not for it), we know that lead has certain effects on the brain. We then make predictions and see if the available data support them.
There are some issues with the methodology. The author had to rely on others’ models to estimate lead exposure where blood data are not available. (Gilsinn, J., 1972. Estimates of the Nature and Extent of Lead Paint Poisoning in the United States. US Department of Commerce, National Bureau of Standards [now NIST].) The author points out when and why these estimates fuzz the picture.
Mielke and Zahran focused on US cities and neighborhoods where we have good data going back to the 50s, and those data support the conclusion as well.
Remember that we’re looking at childhood lead levels. Not exposure in adults.
This entire thread is an excellent example that we can link to when people ask whether we should still teach science to children.
An article in Mother Jones makes a persuasive argument.
It goes on to talk about how the same correlation occurs in other countries, how the crime rates were higher in areas with greater automobile traffic, and how higher lead levels in individuals correlates with higher incarceration rates.