The Rise and the Fall of a Violent Society

How new research can explain the unexpected world wide trends in violent crime reduction.

When someone mentions ‘Lead’ what springs to mind? Chemistry enthusiasts are shouting arrogantly at their screens that, “it it has an atomic number of 82” and, “that the symbol for it is ‘Pb’ which comes from leads Latin name Plumbum”. Plumbers are well acquainted with Lead from their faithful solder, used to join copper pipes making a firm and water tight seal. Roofers will know lead only to well as its malleable surface is perfect for the flashing on the roofs of your houses. But for the rest of us, I can safely assume that we are thinking of a somewhat uninteresting lump of grey metal that isn’t all that good for us when it is in our bodies. But we are wrong! Lead is not an uninteresting lump of grey metal that is rather bad for you, but instead, the most aggressive violent criminal that society has ever seen…

Crime, in western society on a whole, is falling. In the UK there were 9.1m reported crimes in 2011/12, according to the Crime Survey for England and Wales. That is down from 9.7m the previous year, and a whopping 27.2% lower than ten years ago. It is not just the petty stuff. The Office for National Statistics agrees that violent crime had fallen by 7%, and the murder rate has fallen by 14%. Over in the States it is the same story. Murder and robbery rates nearly halved from 1991-98. This phenomenon has saved thousands of lives and spared many more potential victims of crime. The pace of the reduction slowed in the late 90’s but new FBI figures show another sharp drop in crime that began around 2008 and is still continuing now, despite the recent high unemployment. This trend is happening all over the world. But, why?

Many people have stepped up to the plate to explain why this is happening. The first person to stamp his claim that he was the reason the sharp fall in crime was the former Mayor of New York, Rudy Giuliani. In 1982, along with a fair few social scientists, he argued that repairing vandalism in urban areas prevented further crime, an idea known as ‘Broken Windows Theory’. This is still a prominent idea in criminology, but here at Reality Bites we are not buying it. Crime fell in a vast amount of cities over that period, and most did not change their policing policy in the slightest. Whilst this idea of nipping crime in the bud by clamping down on less serious crimes may well affect crime rates, it can’t be responsible for the overall reduction in worldwide violent crime. Sorry Giuliani, no credit for you on this one.

Unlike Rudy Giuliani’s claims, there are lots of proposed theories that are highly likely to be linked to this dramatic drop in crime. A study released last month by Researchers in Texas – working with the Centre for European Economics – suggested video games were keeping young people off the streets, and therefore, away from crime. John Conklin, a sociologist at Tufts University, argues a significant factor behind the fall in crime in the 1990s was the fact that more criminals were locked up and therefore making them unable to offend. A controversial theory was also put forward by economist Steven Levitt, arguing that the

in America after the Supreme Court ruling in 1973 on Roe Vs Wade meant that fewer children were born into socially deprived families. Levitt argues that this stopped unwanted babies in the 1970s and 80s from becoming adolescent criminals in the decades that followed. These can all explain parts of the trend but we are yet to see an argument that shows the driving force that is lowering the crime rate. That was until we came across research from Rick Nevin.

back in 1994 Nevin was working for the US Department of Housing and Urban Development seeing if there would be any befits from removing lead paint from old houses. Recent studies had indicated that Lead poisoning can lead to complications later in life, including lower IQ, hyperactivity, behavioural problems, and learning disabilities. Nevin was the first person to float the idea that maybe reducing lead exposure had an effect on violent crime too?

For the non mechanics among us, I must tell you about a man called Thomas Midgley. An Ohio born inventor who’s mechanical genius was only surpassed by a amazing ability for his inventions to, unintentionally, destroy the world. After inventing CFCs (a gas used in refrigerants, but you may have come across them before they was phased out in aerosol cans) which after he died scientist discovered were destroying the ozone, Midgley set his mind to a completely different problem. A long standing problem with diesel engine at the time was a problem called ’Engine Knock’, where a distinctive knocking noise is caused by the air and fuel mixture being too lean. Midgley realized that by adding lead to petrol solved the problem, but unknown to him, left large amounts of Leaded Gasoline in the air. This was later banned at various stages around the world, and we began to see atmospheric lead levels slowly decline.

Nevin realised this when researching crime rates so compared them to charts showing the rise and fall of atmospheric lead. The charts show Lead emissions rose steadily from the early ’40s until the early ’70s. Then, as leaded gasoline was banned, and unleaded was introduced, emissions plummeted. Violent crime rates mirrored this upside-down U pattern, only offset by about 20 years. The data showed in places where uses of leaded gasoline declined slowly, so did crime. Where it declined quickly, crime also declined quickly. Nevin concluded that if you add a lag time of 23 years, lead emissions from auto mobiles explain the vast majority of the variation in violent crime. Toddlers who inhale high levels of lead in the ’40s and ’50s really were more likely to become violent criminals in the ’60s, ’70s, and ’80s. His research showed this was not just in America. Everywhere he could get crime statistics, and data on atmospherics lead levels, you can see an identical situation. Further studies on this by Howard Mielke, working with Sammy Zahran, furthered this research and found that there was an over whelming correlation of atmospheric lead levels and crime even on a street by street basis. Looking at six US cities they found that even at this concentrated level, when they overlay maps showing high quantities of atmospheric Lead with the crime hot spot maps, they match up.

This idea is not only backed up by statistics, but by common sense. Top scientists have known for years that lead poisoning causes damage to our brains. In 1995, the American Academy of Paediatrics reviewed 18 scientific studies on the correlation between a child’s mental abilities and lead levels in their blood and found that the relationship between lead levels and IQ deficits was “remarkably consistent”. A study by Herbert Needleman in 1996 measured boy’s behaviour at age 7 and again at age 11and found that those who had more lead in their bones consistently had more reports of aggressive and delinquent behaviour, and problems paying attention. They were more likely to engage in antisocial activities like vandalism, truancy, and shoplifting. Furthermore, their behaviour got worse as they grew older. There is no end to studies that link lead to these types of behaviours. Modern research shows that lead poising tends to affect our use of our pre-frontal cortex – the part of the brain associated with personality expression, decision making and moderating social behaviour – so baring in mind this research, can we be surprised with Nevin’s findings?

This isn’t a problem that will be solved over night. Even if we did remove every drop of atmospheric lead from our streets we would not completely solve violent crime as there is a vast amounts of causes for it, but can we really ignore this? Like most good science, this has fallen on deaf ears. There is minimal political push around the world for this to be addressed. Most politicians, like good old Rudy Giuliani, are happy claiming that there policies are the reason for this drop in crime, but like usual statistics can expose what is really going on. There are two things we believe that everyone should take from this. First, around the world we are cutting Environmental health departments as we strive to save money, cut deficits and reduce country debts. But is this really saving money? If you add up the cost of processing all that crime; including policing, court fees, prisons, etc it would tower over spending on the environment. Support our environmental departments; don’t let politicians talk you into believing that we cannot afford to run them. And second, if you ever plan on being an inventor, please read more about Thomas Midgley and whatever you do, don’t follow in his footsteps.

One of the Graphs from Nevins study

One of the Graphs from Nevins study

Nevin – Understanding international crime trends: The legacy of preschool lead exposure

Howard Mielke – The urban rise and fall of air lead (Pb) and the latent surge and retreat of societal violence

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37 Responses to The Rise and the Fall of a Violent Society

  1. andersays says:

    lest we forget Rome and its lead pipes…

  2. Dan says:

    Another issue may be the reduction in reported crime in inner cities. While this is unlikely to be the case for murders, in some inner city neighbourhoods the perceived futility of reporting crimes may lead to stats looking better.

  3. Suzie says:

    Unfortunately, many lipsticks and other cosmetics contain heavy metals such as lead. Why aren’t people more alarmed?

  4. adunadura says:

    This is one long post lol

  5. Jack Curtis says:

    They tell me that murder rates have been falling for 100 years. Crime rates generally have been found to be high in cities before cars were prevalent as well as after. Crime seems to correlate well with the corruption level in a given society as well as with other factors like unemployment, education and Pb in the air.I’m guessing that the general morality of a society sets some sort of baseline and varies among different societies, but I don’t know that. We meed more research than we seem to get; adding lead to the list of booze and drugs seems progress…

  6. pzykr says:

    the backstory why lead was used in gasoline instead of the better, cheaper, and safer alcohol (which was already known to be better when they started using lead and which is now required by law) is very ugly, stinks of greed, and to this day taints the oil industry. in short — collusion between rich robber barons (duponts and rockefellers among others)…

  7. pzykr says:

    found a better link to the full article cited in my last comment — no need to sign up for trial membership to finish reading…

    “the secret history of lead”

  8. drenn1077 says:

    Let’s not forget mercury. It too can lower IQ’s and lead to such aggressive behavior. Also, did you know that tooth fillings contain mercury?

  9. Heavy metals and other environmental factors play obviously huge roles in violence. The Freakonomics guys claim the legalization of abortion was the key to the 90’s crime drop ( I’d also give a nod to the rise of feminism. One of the shockingly wonderful accomplishments of our generation sez me, is the fact that rape in the US has been reduced by more than 80%

  10. Jeevie says:

    Thank you for liking my blog, your blog is very interesting. You should read Better Angels by Steven Pinker, it is about the decrease in violence in recent times. I haven’t read it because I’m only 10 – It is over 800 pages long. But my dad told me about it and I read on Wikipedia what it’s about. You should read my post about video game addiction (

  11. It might be even more staggering to think of all the other pollutants of an industrial society and how they might be affecting people, maybe young people in particular. Lead is bad enough; there may be a lot of other additives to food, water and atmosphere that are having adverse effects too. Some of them we may suspect; others we probably have no idea about. Good article, and thanks for liking my post.

  12. reocochran says:

    I think you have some good writing and analysis style here! I appreciate your stopping by my blog, will get back after I make my way to work and then home in 10 hours today! Yikes! My hump day is always the worst day of the week at the distribution center!

  13. Thanks for checking out sciencesprings.

  14. pzykr says:

    btw — thanks for the great post!
    you turned my brain on with this high-grade info
    kick-started me into high gear
    left my manners behind…
    thx esp for including the links to the original research

  15. kyrian says:

    Thanks for sharing

  16. wodezitie says:

    Very interesting take on crime… Having lived in NYC for a long time, I’m not sure I trust the statistics here. People, mostly poor, where violence is higher in those populations, have been pushed out further and further as neighborhoods become increasingly gentrified. “The Wire” really hit home when it showed that, in many ways, society actually advocates a separate society and separate financial system for people who have been disenfranchised, and how are those statistics kept (or not)? The disenfranchised have far less opportunities for meaningful employment. As far as violence as a whole in our society or worldwide, I’m totally unsure about violence increasing or decreasing… But as you point out, lead exposure can be a real factor. Thanks so much for your interesting post!

    • We agree that the statistics may not be accurate for all crime, yet murder is slightly harder to juggle the numbers as you have a dead body that needs accounting for! Nevin took this into account on his study. Your other point we tend to agree with, although the research in that is still not certain. Thank you for commenting.

  17. xenophobia22 says:

    This was much more like a PhD thesis than a blog. (Which was fascinating for me.) I understand that pollution is a factor in violent behaviors, but over-crowding, exposure to violence on television, movies, and videos also plays a significant role. We should also teach morals in schools, so our children can have a clear picture of right and wrong. Most importantly, we need to teach our children to socialize. Staring at a computer screen, texting, emails, tweets… when do they have “FACE-TIME” with each other? We are breeding Robots.

    • Thank you so much for reading and contributing. We do disagree with your points though. There is no research that shows over crowding has any links to violence. If anything, work in economics show that highly populated area are safer than less populated ones (see Tim Harfords ‘The undercover economist’). In the famous bobo doll experiment where they looked at how people behave after seeing violence on tv they concluded that, while it could make children act slightly more aggressive, It was not a major influence in people becoming violent. Other study’s have backed this up. As for breeding robots

      • Hey Reality Swipe, I think you might be onto something, but I think this is something that could be extended further. I don’t have data to back it up, but I’ve been wondering about the physical basis of conditions like bipolar disorder, for instance. I had a friend with cyclical depression, who got depressed every year at the same time. It’s difficult to believe that this happened from merely psychological factors. I think there are physical factors at work too, but the little research I’ve done indicates that nobody is very sure how depression works on a physical basis. It makes me wonder if pollutants of various kinds (and we’ve got a lot of them in our environment now) doesn’t have to do with these and other conditions like chronic anxiety, autism, etc. Again, not enough data to say, but I do wonder.
        And thanks for liking my post.

  18. Waverider1 says:

    Add ‘Global Paradigm Shift’ to your list of potential ’causes’ for the drop in violent crime AND the increase in (generally unreported in MSM) acts of kindness and generosity and cooperation and unity — and that just might fill in the missing pieces. This year shall see it happen. Beginning RIGHT NOW.

    ‘People say I’m crazy, but I’m not the only one. . . . I hope someday you’ll join us, and the world will BE as One. . . . ‘ Welcome to the beginning of John’s Great Vision becoming our actual collective reality. Just a bit more patience, and active support for all that is Universally Good and Just, and we shall manifest a much better world — for ALL (even the oligarchal 1%!). A few words of hope from this fool on the hill. . . ..

  19. suenitz2013 says:

    Fascinating, and it does make sense. I wonder what lead levels would be for serial killers? Potentially very high.

  20. oogenhand says:

    Reblogged this on oogenhand and commented:
    Interesting environmental take on this, but it could also be that crime is less reported.

  21. Farm-Art-Think says:

    Thanks for an interesting and very convincing post!

    A few years back George Monbiot looked at a similar violence-link, to poor diet: Seems like lead is a major factor but possibly is not the only environmental cause for bad behaviour. What do violent offenders eat for dinner?

  22. beetleypete says:

    Thanks for the follow on my blog. ( Your blog is highly academic, and a world away from my efforts. I like this lead theory, as I like all theories about most things really. Good work, Regards from Norfolk (England). Pete

  23. gpicone says:

    Great post! Now we just need to get rid of Tuna fish!

  24. lubkin2013 says:

    Please read my blog: VIOLENT CRIME DOWN…I DON’T THINK SO!

  25. Pingback: A link between lead and violent behaviour? | Rodney Willett

  26. I like the broken window theory and how significant it is to prevent crime, great article

  27. ozob says:

    “First, around the world we are cutting Environmental health departments as we strive to save money, cut deficits and reduce country debts. But is this really saving money? If you add up the cost of processing all that crime; including policing, court fees, prisons, etc it would tower over spending on the environment. Support our environmental departments; don’t let politicians talk you into believing that we cannot afford to run them.”

    Is there enough data to estimate the related costs and relative cost savings of “investing” in toxic environmental cleanup for later crime reduction? That seems like a good next step to formulate a solid policy argument…

  28. Noitartst says:

    Neat article, Reality Swipe; made me muse.

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