Crime is down because of less lead?

[wgbgator]

Seems crazy, but somewhat persuasive too.

http://www.motherjones.com/kevin-dru...ime-connection

I've written several posts recently about the idea that America's great crime epidemic, which started in the 60s and peaked in the early 90s, was caused in large part by lead emissions from automobiles. Long story short, we all bought lots of cars after World War II and filled them up with leaded gasoline. This lead was spewed out of tailpipes and ingested by small children, and when those children grew up they were more prone to committing violent crimes than normal children. Then, starting in the mid-70s, we all began switching to unleaded gasoline. Our kids were no longer made artificially violent by lead poisoning, and when they grew up in the mid-90s they committed fewer violent crimes. This trend continued for two decades, and it's one of the reasons that violent crime rates have dropped by half over the past 20 years and by more than that in our biggest cities. It's one of the great underreported stories of our time: big cities today are as safe as they were 50 years ago.

That's the short version of the story. The long version of the story is on the cover of the current issue of Mother Jones, and today it's available online for the first time. Click here to read it. The chart on the right illustrates the basic data that inspired the lead hypothesis: it shows lead emissions starting in 1935 overlaid with the violent crime rate 23 years later. The two curves match almost perfectly.

[Dreamliner]

Lead must be up in Chicago then.

[mdgator05]

There is a lot of good work that has been done on this issue, including some pretty solid predictive models around the world of when the dramatic dropoff in crime would occur.

A good example of the need for a solid environmental program and the existence of the tragedy of the commons, where people were victims of violent crime at a higher rate due to a decision that was individually rational but socially irrational.

[Dreamliner]

This is good news on another front. If it really turns out to be the environment, then we no longer have to bother with quaint terms like 'right and wrong' and 'good and evil.'

[wgbgator]

Originally Posted by Dreamliner

Lead must be up in Chicago then.

Eh, not really. Chicago fits the downward trend too.

1974: 970 murders
2012: 506 Murders (up from 2011's 435, the lowest # in decades)

[Dreamliner]

Originally Posted by wgbgator

Eh, not really. Chicago fits the downward trend too.

1974: 970 murders
2012: 506 Murders (up from 2011's 435, the lowest # in decades)

Yep, lead is up this year. It's the environment, stupid.

[mdgator05]

Originally Posted by Dreamliner

Yep, lead is up this year. It's the environment, stupid.

Lead exposure is an issue amongst children. That is why there is about a 20-25 year lag. It is unlikely that lead exposure is up this year. In fact, we are probably reaching the point where crime declines will slow somewhat, as the lead exposure in childhood for young adults has pretty much cratered to very low levels. We might get some slight continued declines due to the fact that crime likely has an autoregressive component, but we are likely to see more random movements in crime than we have experienced over the last 20 years due to the fact that lead levels had really cratered by the mid 1980s.



As for getting rid of the whole correlation does not equal causation counterpoint, the author effectively dealt with that:

Not only does lead promote apoptosis, or cell death, in the brain, but the element is also chemically similar to calcium. When it settles in cerebral tissue, it prevents calcium ions from doing their job, something that causes physical damage to the developing brain that persists into adulthood.

Only in the last few years have we begun to understand exactly what effects this has. A team of researchers at the University of Cincinnati has been following a group of 300 children for more than 30 years and recently performed a series of MRI scans that highlighted the neurological differences between subjects who had high and low exposure to lead during early childhood.

One set of scans found that lead exposure is linked to production of the brain's white matter—primarily a substance called myelin, which forms an insulating sheath around the connections between neurons. Lead exposure degrades both the formation and structure of myelin, and when this happens, says Kim Dietrich, one of the leaders of the imaging studies, "neurons are not communicating effectively." Put simply, the network connections within the brain become both slower and less coordinated.

A second study found that high exposure to lead during childhood was linked to a permanent loss of gray matter in the prefrontal cortex—a part of the brain associated with aggression control as well as what psychologists call "executive functions": emotional regulation, impulse control, attention, verbal reasoning, and mental flexibility. One way to understand this, says Kim Cecil, another member of the Cincinnati team, is that lead affects precisely the areas of the brain "that make us most human."

[Dreamliner]

It's also unlikely that lead was ever making us violent. Seriously, there is a poster on Too Hot who earnestly believes that fake blueberries are killing us.

[mdgator05]

Originally Posted by Dreamliner

It's also unlikely that lead was ever making us violent. Seriously, there is a poster on Too Hot who earnestly believes that fake blueberries are killing us.

Except for the fact that science has determined that lead exposure in childhood makes individual people more violent and the aggregate exposure rates seem to match up very closely with aggregate violence rates, a result that has been replicated across a wide variety of cultures, including our own.

If you are going to challenge pretty well established science, it helps to have something to work with beyond not wanting something to be true.

[Dreamliner]

Originally Posted by mdgator05

Except for the fact that science has determined that lead exposure in childhood makes individual people more violent and the aggregate exposure rates seem to match up very closely with aggregate violence rates, a result that has been replicated across a wide variety of cultures, including our own.

If you are going to challenge pretty well established science, it helps to have something to work with beyond not wanting something to be true.

So, did we get bored with all the other factors that may occasion violence ? Is lead exposure sexier ? It certainly sounds more insidious.

My advice would be to wait for critiques of this study to roll in. Also, factor in new and exciting theories such as the addition of flouride to water supplies over the last few decades. You know, the Nazis used it on the Jews as a tranquilizer.

[mdgator05]

Originally Posted by Dreamliner

So, did we get bored with all the other factors that may occasion violence ? Is lead exposure sexier ? It certainly sounds more insidious.

My advice would be to wait for critiques of this study to roll in. Also, factor in new and exciting theories such as the addition of flouride to water supplies over the last few decades. You know, the Nazis used it on the Jews as a tranquilizer.

The examination of a major factor in violence does not prevent the examination of other factors. But lead exposure has been researched for quite some time, leading to plenty of time for critiques to examine this issue. Here is an article from 2007 outlining the research done by an economist on lead exposure and violent crime across 9 different countries.

http://www.washingtonpost.com/wp-dyn...070701073.html

Nevin says his data not only explain the decline in crime in the 1990s, but the rise in crime in the 1980s and other fluctuations going back a century. His data from multiple countries, which have different abortion rates, police strategies, demographics and economic conditions, indicate that lead is the only explanation that can account for international trends.

Because the countries phased out lead at different points, they provide a rigorous test: In each instance, the violent crime rate tracks lead poisoning levels two decades earlier.

"It is startling how much mileage has been given to the theory that abortion in the early 1970s was responsible for the decline in crime" in the 1990s, Nevin said. "But they legalized abortion in Britain, and the violent crime in Britain soared in the 1990s. The difference is our gasoline lead levels peaked in the early '70s and started falling in the late '70s, and fell very sharply through the early 1980s and was virtually eliminated by 1986 or '87. In Britain and most of Europe, they did not have meaningful constraints [on leaded gasoline] until the mid-1980s and even early 1990s," he said. "This is the reason you are seeing the crime rate soar in Mexico and Latin America, but [it] has fallen in the United States."

The centerpiece of Nevin's research is an analysis of crime rates and lead poisoning levels across a century. The United States has had two spikes of lead poisoning: one at the turn of the 20th century, linked to lead in household paint, and one after World War II, when the use of leaded gasoline increased sharply. Both times, the violent crime rate went up and down in concert, with the violent crime peaks coming two decades after the lead poisoning peaks.

I have hit the four paragraph limit, but continue reading on the second page for a variety of other research projects that have examined this issue. The first shows that counties with higher lead exposure amongst children have 4x higher murder rates, controlling for socio-economic factors. Other studies show that violent criminals have much higher rates of lead exposure than the general population. As pointed out by the Johns Hopkins Prof, none of this stuff is seen as that controversial right now in scientific communities.

[Dreamliner]

Hmm, lead must be up (or flouride or abortions or violent video game sales up) in a number of US cities not cooperating with the trends.

[mdgator05]

Originally Posted by Dreamliner

Hmm, lead must be up (or flouride or abortions or violent video game sales up) in a number of US cities not cooperating with the trends.

As stated in the article I just posted, lead exposure cratered in the US in the mid 1980s. Applying the 20-25 year lag, you see that crime rates due to lead exposure in the US should have cratered about 2005-2010. Now we are likely seeing a return to a more random walk sort of time series, in which random effects increase and decrease crime in different locations. So while overall violent crime is still declining, a normally distributed change from a previous point will result in a greater number of local increases.

[Dreamliner]

Originally Posted by mdgator05

As stated in the article I just posted, lead exposure cratered in the US in the mid 1980s. Applying the 20-25 year lag, you see that crime rates due to lead exposure in the US should have cratered about 2005-2010. Now we are likely seeing a return to a more random walk sort of time series, in which random effects increase and decrease crime in different locations. So while overall violent crime is still declining, a normally distributed change from a previous point will result in a greater number of local increases.

And as I just stated, some cities are defying the trends. This is a confounder that has to be accounted for. And I doubt that these studies have controlled for 'social factors' at least as likely to contribute to fluctuations in crime.

[oragator1]

And when did the baby boomers go through their peak crime years? I think you will see another correlation not dissimilar from the lead chart.
I have no problem with lead being looked at, it's interesting and probably has some merit, I just think the chart is a bit simplistic for something that probably has dozens of contributing factors.

[mdgator05]

Originally Posted by Dreamliner

And as I just stated, some cities are defying the trends. This is a confounder that has to be accounted for. And I doubt that these studies have controlled for 'social factors' at least as likely to contribute to fluctuations in crime.

You don't seem to understand what is going on with this research. Again, crime due to lead exposure should have cratered between 2005-2010. So any variation now is unlikely to be due to lead exposure issues. Now we are likely looking at a random walk, since lead exposure has worked its way out of the environment for the most part in most of the US.

BTW, that isn't a "confounder." A confounding variable would be a variable that correlates with both the independent and dependent variable. You did not suggest a confounding variable nor provide any evidence of this confound.

These studies have controlled for a huge number of socio-economic factors or, in the case of Nevin, used an international dataset that allowed for the controlling of these variables through differences in countries. For example, it allows the author to rule out abortion because it was made legal earlier in Britain, but the increase in violent crime occurred in the 1990s, which coincides with the fact that British lead levels didn't start dropping until later than in the US.

[mdgator05]

Originally Posted by oragator1

And when did the baby boomers go through their peak crime years? I think you will see another correlation not dissimilar from the lead chart.
I have no problem with lead being looked at, it's interesting and probably has some merit, I just think the chart is a bit simplistic for something that probably has dozens of contributing factors.

It is possible that demographic issues was a secondary causal factor, but it is unlikely a primary cause as this relationship has been shown internationally at different points in time, which would not coincide with the Baby Boomer demographic change.

[oragator1]

Originally Posted by mdgator05

It is possible that demographic issues was a secondary causal factor, but it is unlikely a primary cause as this relationship has been shown internationally at different points in time, which would not coincide with the Baby Boomer demographic change.

Do you have any charts on other countries, I would be interested in seein them.

[Dreamliner]

Originally Posted by mdgator05

You don't seem to understand what is going on with this research. Again, crime due to lead exposure should have cratered between 2005-2010. So any variation now is unlikely to be due to lead exposure issues. Now we are likely looking at a random walk, since lead exposure has worked its way out of the environment for the most part in most of the US.

BTW, that isn't a "confounder." A confounding variable would be a variable that correlates with both the independent and dependent variable. You did not suggest a confounding variable nor provide any evidence of this confound.

These studies have controlled for a huge number of socio-economic factors or, in the case of Nevin, used an international dataset that allowed for the controlling of these variables through differences in countries. For example, it allows the author to rule out abortion because it was made legal earlier in Britain, but the increase in violent crime occurred in the 1990s, which coincides with the fact that British lead levels didn't start dropping until later than in the US.

You don't seem to want to acknowledge that a number of cities are simply not cooperating with your convenient hypothesis. There are cities where crime is, in fact, soaring and not rebounding to a 'normal walk', as you put it.

Now, lead exposure might be *a* factor in crime, but how much of a factor ? On the other hand, even studies showing lead exposure affecting IQ have been called into question.

I agree with oragator. This is far too simplistic. I could just as easily argue that government policy has exacerbated crime rather than ameliorate it.

[oragator1]

By the way, one other point on violent crime, it's been generally dropping for 450 years: