For the past 70 years or so, crime has mainly been explained through socio-economic factors such as housing or level of education. Currently the focus has shifted more to neuroscience and biology – and the idea that a chemical imbalance might also cause someone to be more violent or prone to criminal behavior.
One of the most mind blowing studies in this field was conducted by economist Rick Nevins. Back in 2001, he found a direct causality between atmospheric lead (created primarily by leaded gasoline emissions and lead paint) and criminality as well as other psychological, physical, and behavioral damage. Exposure to lead in pregnant mothers, for example, can cause their child to develop schizophrenia once they grow up, while even small concentrations may lower the IQ of kids exposed to lead.
The causality is so blatant that Tulane University researchers Howard Mielke and Sammy Zahran found that when neighborhood maps of lead contamination and crime statistics in New Orleans were overlapped, they were nearly identical.
The time frame also coincided perfectly. American children in the 1940’s and 50’s were exposed to large amounts of atmospheric lead and later grew up to commit violent crimes in the late 60’s through the 1980’s. Lead wasn’t removed from gasoline until the EPA passed the Clean Air Act in 1970, which subsequently saw blood lead levels in children fall by 75% between 1976 and 1991. And because blood lead contamination has been linked to reduced IQ levels and aggressive and delinquent behavior, statisticians saw crime rates falling alongside lead levels.
The phenomenon was not limited to New York City or even the United States; Nevins found that in places like Australia, West Germany, Canada, Finland, and the United Kingdom, blood lead level graphs always matched up to violent crime graphs. Households and neighborhoods with high levels of lead contamination also have environmental factors that further contribute to criminal behavior: lower-income neighborhoods frequently fall victim to poor city planning, often being crammed between highways in bleak, industrial sectors of the city where unkempt streets and hallways produce great amounts of lead-ridden dust and debris.
More than a decade has passed since the Chicago Tribune published a front-page story stating that the legalization of abortion in the US in the 1970’s could explain 50 percent of the amazing decline in crime in the 1990’s. The idea: some of the children who were not born thanks to the legalization of abortion, were children who would have grown up to be individuals who were more likely to commit crime.The story, based on the then still unpublished manuscript by economists John Donohue and Steven Levitt, obviously ruffled some feathers – and still does.
In their book on the subject, titled Freakonomics, Donohue and Levitt note: “This theory is bound to provoke a variety of reactions, ranging from disbelief to revulsion, and a variety of objections, ranging from the quotidian to the moral. The likeliest first objection is the most straightforward one: is the theory true? Perhaps abortion and crime are merely correlated and not causal.”
Now, more than ten years later, much more research has been done in the field. Were Donohue and Levitt right? The jury is still out. In 2005, a team of economists from Lancaster University put the hypothesis to test in a different environment, namely the UK. Their conclusion: having more children in care means more crime, as well as higher unemployment rates. However, the authors note that they “are unable to say with confidence that abortion legalization in the U.K. significantly reduced crime in England and Wales some twenty years hence.” They conclude this because the crime rate in Britain dropped at the same time as it did in the US, while abortion legalization occurred about five years earlier.
Wellesley College Professor Phillip Levine, researches the impact of abortion policy changes on pregnancy, abortion, and birth. In an interview with The Atlantic, he does not go as far as saying the legalization of abortion was economically beneficial, but he does state that this had a dramatic impact on women’s fertility, which, in turn, affected the “kind” of babies that were born. “You observe increases in college graduation, lower rates of welfare use for the children themselves, reduced likelihood of becoming a single parent themselves. These are outcomes for the children who were born in the early 70s that we observe 20 years later, that we observe for the cohort as a whole. Because it’s a different group of children born relative to those who would have been otherwise. That’s not to say that’s a good thing, that’s just what happened.”
Science has long pointed out the health benefits for those who live in the proximity of trees, yet last year it became apparent that nature might also keep you safe. Researchers Geoffrey Donovan and Jeffrey Prestemon found that in Oregon, certain types of trees help lower property and violent crime rates.
Donovan and Prestemon used crime data from the Portland Police Bureau from 2005 to 2007. Their sample of 2,813 single-family homes experienced 394 property and 37 violent crimes. They compared these with additional data obtained from aerial photos and onsite visits, to determine the level of vegetation near these houses.
Their conclusion was certainly interesting: the presence of large trees was associated with a reduction in crime, while small trees were linked to an increase. “We believe that large street trees can reduce crime by signalling to a potential criminal that a neighborhood is better cared for and, therefore, a criminal is more likely to be caught,” Donovan said. “Large yard trees also were associated with lower crime rates, most likely because they are less view-obstructing than smaller trees.”
And the crime-lowering effect of trees is not just in Portland; a 2013 study conducted in Philadelphia showed similar results. However, it isn’t only large trees that have proven to be beneficial, grass and shrubs also show a positive correlation. The authors of this study therefore suggest the “tree-effect” is rooted in the fact that well maintained greenery encourages social interaction and community supervision of public spaces, as well the “calming effect” that vegetated landscapes might have on burglars-to-be. And hey – if it doesn’t fight crime, at least it looks nice. As researcher Donovan puts it: “Although a burglar alarm may deter criminals, it won’t provide shade on a hot summer day.”
The practice of name bullying is probably as old as time – and is not going away with baby names like Zealand and Yoga still being thrown around. A 2009 study suggests that having an odd name might eventually cause someone to fall into evil ways. The research, conducted by David Kalist and Daniel Lee of Shippensburg University, showed that youngsters with unpopular names, regardless of race, are actually more prone to committing a crime.
How did the researchers come to this unusual conclusion? They analyzed state data by comparing first names of male juvenile delinquents to first names of male juveniles in the population. With this information they created a popularity-name index (PNI). The most popular name (meaning most frequently used), for example Michael, has a PNI of a 100. A mediocre popular name, such as David, has an PNI of 50. Names such as Alec, Ernest, Ivan, Kareem and Malcolm only had a PNI of 1 – these were most likely to end up in juvenile detention.
The researchers found that for every 10 percent increase in a name’s popularity, there was a 4 percent decrease in the number of juvenile delinquents of the same name. The name-crime link is interesting, yet obviously is not always predictable. FBI’s current “Ten Most Wanted List”, for example, includes a David, as well as a Richard and a William. The authors of the study also stress that the names alone are probably not the reason these kids commit crimes, yet do indicate other problems associated with having a low socioeconomic status.
Still, they don’t exclude the option that having an unusual name in itself might cause problems, when children are bullied because of it, or when their peers consciously or unconsciously act out because of it. “First name characteristics may be an important factor to help identify individuals at high risk of committing or recommitting crime, leading to more effective and targeted intervention programs,” the authors conclude.
In line with the idea that ‘more trees means less crime’ is the broken window theory – just like the presence of trees and grass can have a calming effect, signals of urban disorder (graffiti, broken windows, garbage) increase the chance that people misbehave.
The theory, that was first mentioned by social scientists George Kelling and James Wilson in 1982, became subject of much debate – especially because it also became the foundation for new and more aggressive “order-maintenance policing” strategies, for example in New York City. Critics claimed that Broken Windows was racist, it harassed and criminalized the poor, and that it constituted cultural imperialism.
Whether these allegations are true or not, more recent research does suggest that environmental factors affect human behavior – in particular our tendency to break rules. In 2008, three researchers from the Dutch University of Groningen conducted six experiments that all confirmed that theory. In one of them, they set up a mail box that contained an envelop with five Euros inside. When the mail box was covered with graffiti, 27 percent of the people who passed by took the money. When the mail box was clean, only 13 percent did so.
The Dutch researchers support the Broken Windows theory, yet do believe it needs to be more nuanced than it was originally. “The misdemeanours in our research escalate from littering to stealing. Once disorder has spread to the level of stealing, simply undoing this by cleaning up is no longer an option. In that stage, it is necessary to again create support for the legitimacy of the rules. That process is much harder and takes much longer than simply sweeping the streets. “
References: Keizer, K., Lindenberg, S., & Steg, L. (2008). The Spreading of Disorder Science, 322 (5908), 1681-1685 DOI: 10.1126/science.1161405
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