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PRI's Environmental News Magazine

Lead and Crime: Profile of Roger Masters

Air Date: Week of December 10, 1999

Living On Earth travels to rural Vermont to meet a retired professor of government with some unorthodox ideas about crime. For the past six years, Roger Masters has been researching the link between heavy metal poisoning and violent crime. He is convinced he’s made important findings, but most scientists are skeptical.


CURWOOD: In a little farm house, near the Vermont-New Hampshire border, there is a man doing research that could forever change the way we look at crime. His name is Roger Masters. He is a retired professor of government at Dartmouth College, and he thinks crime rates are determined, at least in part, by toxic chemicals taken into the human nervous system. It's a controversial theory, one that is scoffed at by many scientists. But if Dr. Masters is right, it could have enormous implications for social policy, and suggest potential ways to reduce crime. So, we traveled up to Vermont to meet Professor Masters at his home.

(Door opens)


MASTERS: You can come in. Hi, Steve.

CURWOOD: Hi, how are you? Good to see you.

MASTERS: Hi, welcome. Good to see you again.

CURWOOD: The walls of Roger Master's office are filled with books on every conceivable subject: Shakespeare, Marx, deTocqueville. He's written on everything from neurotransmitters to the nonverbal behavior of politicians. But what brings us here is Professor Masters' pioneering work in the area of heavy metals and crime. It started around 1993, when Vermont's Commissioner of Corrections asked Professor Masters to look into the possible biological factors leading to crime. This led him to the work of a California businessman named Everett Red Hodges. Mr. Hodges had a theory that exposure to manganese, sometimes used to boost the octane of gasoline, also boosted the incidence of antisocial behavior. At first, Roger Masters had his doubts.

MASTERS: I was skeptical, because it seemed very, very far out. So I said, "Red, if you're right, where there's environmental pollution with manganese, there should be more crime." He said, "That's right." I said, "Well, I'll check that."

CURWOOD: Comparing data from the EPA's Toxic Release Inventory with national violent crime statistics, Professor Masters made a discovery. In communities polluted by manganese and lead from industrial sources, the crime rate was more than twice as high as in areas where neither toxin was emitted by industry. The difference held even after Professor Masters controlled for factors normally associated with crime, such as race, income, population density, and unemployment. Professor Masters was convinced he was onto something.

MASTERS: Usually in crime, we hear that, well, so and so did a good job as the commissioner of police in New York, or Toledo, Ohio, or so forth. But if you have a national trend in crime, it can't be just one chief of police. If you have national trend on three or four things, and they are all connected with controlling impulses, then there must be something at the level of the chemistry of the brain.

CURWOOD: Specifically, the parts of the brain that regulate impulses. Here's how it works. When heavy metals like lead and manganese get into the bloodstream, they reduce levels of dopamine, a neurotransmitter that helps people inhibit their impulses. So he says, you'd expect people with higher lead levels to have a harder time controlling their impulses. Dr. Masters also found that in communities already exposed to lead and manganese, crime rates were even higher, when you factored in that well-known disinhibitor, alcohol.

MASTERS: If you take the counties where there are all three of those risk factors, the crime rates are tripled. Over 900 per 100,000; the national average is a little under 300. And this always controlling for 24 other factors that are conventionally connected with crime.

CURWOOD: Nationwide, more than 50 counties fit this description. There are the usual suspects, like Los Angeles, Philadelphia, and St. Louis, but also plenty of smaller counties you might not immediately think of as high crime areas: places like Chesterfield, South Carolina; Neosho, Kansas; and Davis, Iowa.

MASTERS: The factors that we traditionally associate with crime are probably clearly associated with crime. Not every poor individual goes out and kills someone. Not everyone from a broken home kills someone. What we have to understand is that human behavior is usually the result of many factors, and that most of the competing explanations are probably all correct. My concern is that we need to look at why it is that within some poor families that are broken, where people are unemployed and living in poor environments, there are criminals, and in others there are not criminals.

CURWOOD: Then Professor Masters shows me a graph that at first would seem to contradict his theory. The drop in crime during the past decade, which he attributes to the banning of lead from gasoline in 1977. Professor Masters says it's no coincidence that the drop in crime followed the lead ban.

MASTERS: When you look at the curves, the decline is just plain extraordinary. It's a 15-year lag. That is, you have to take 15 years after the gas has no longer got lead in it, and look at those kids. It takes 15 years to grow a criminal.

CURWOOD: So far, Professor Masters' work has been largely ignored by the established scientific community. The Journal of the American Medical Association recently published an issue devoted entirely to new research on violence, but you won't find Roger Masters' work in there. And in the spring of 1999, many prominent scientists and researchers were invited to New York City to participate in a landmark conference on environmental influences on child development. The scientists sat on the stage and presented their latest research. When Roger Masters spoke, it was from an audience microphone on the floor.

WOMAN: Do we have a question? Over here.

MASTERS: (Speaking in microphone) My name is Roger Masters from Dartmouth College. I thought one thing was missing this morning, which was very dangerous to miss, which is the court's reversal of the EPA's air quality rules. We find that lead pollution is highly correlated with declines in -- or the rate of violent crime. I've just seen some numbers that some students...

CURWOOD: One researcher with concerns about Roger Masters' conclusions is Dr. Herbert Needleman, considered by many to be the father of lead research in this country. Dr. Needleman, a professor of psychiatry and pediatrics at the University of Pittsburgh School of Medicine, has done some of his own work in this area. In 1996 he published a study showing a correlation between the level of lead in bones and juvenile delinquency. But Dr. Needleman's work looked at the effect of lead on individuals, while Dr. Masters' work compares large groups. And Dr. Needleman says that approach is the fundamental problem with Professor Masters' work.

NEEDLEMAN: In order to prove causality, you have to measure the toxic agent in an individual and measure the behavior of that individual. Short of that, you can't say that there's a cause-association, and even if you have those two measurements you have to be very modest in saying that one causes the other.

CURWOOD: Roger Masters says he's not claiming that exposure to heavy metals alone causes crime, only that it may be one factor. And he isn't the only researcher saying so. Deborah Denno, a law professor at Fordham University in New York, has also researched the link between lead and crime, and has come to many of the same conclusions as Professor Masters. She says research like this that cuts across disciplines will always run into resistance from scientists who are protective of their fields.

DENNO: What do I know about lead? I'm a sociologist. I didn't take these data; I didn't take these measurements. They're absolutely right about that. I'm not a medical doctor. And, you know, my response is that's not the role I'm trying to take here. I'm a sociologist looking at correlation among variables.

CURWOOD: Professor Denno says any lack of attention or slighting of Professor Masters' work is mainly a case of professional territoriality. But she has strong praise.

DENNO: Well, I think very highly of him. I think he is innovative and creative and deserves a lot of credit for looking at this relationship, because I think he's gotten a bit of a hard time about it.

CURWOOD: Innovative, creative. Words often used to describe Roger Masters' work. But he'll be as quick to tell you, courage and creativity don't get you published in the major journals. It's a frustrating reality for him, but not defeating.

MASTERS: If I have to choose, in other words, between making the most decent effort I can to getting an answer to the question of environmental factors associated with crime or drug use, on the one hand, or getting into a prestigious journal on the other, I don't balance the second. I want to get it right. And, you know, that's what counts, and usually the prestige comes when it comes.

CURWOOD: A little of that prestige may have come last year, when the Environmental Protection Agency gave Roger Masters $50,000 to continue his research. But the grant is only a fraction of what would be needed to conduct the kind of detailed, controlled research that could rigorously test Dr. Masters' ideas, and prove or disprove that toxic substances contribute to crime.



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