Many theorize that environmental lead levels that began increasing in the 1960s, contributed to the increase in societal violence from the 70s through the 90s. Suspiciously, crime levels began declining in the 90s. One of the many facts pointing to this belief includes the amount of lead found in the environment. Another consideration involves concrete scientific studies indicating the affect that the metal has on behavior. Lastly, fluctuating lead levels and behavioral changes occurred worldwide.
Until the 1970s, manufacturers used Pb(CH2CH3)4, known as tetraethyl lead as a component in paint, plumbing and as an anti-knock constituent in gasoline. Research eventually revealed that lead had toxic effects and subsequently, the governmental initiated a ban on lead. The air, soil and water in many locations may continue harboring the toxic metal. However, levels do not usually reach the quantities commonly found in earlier decades.
Beginning in the 1970s, physicians determined that lead poisons the brain and causes irreversible damage. The metal decreases cognitive function, which lowers intelligence. Lead interferes with analytical and reasoning abilities. The metal traveling from the blood to the brain also inhibits decision-making ability while affecting attention span, emotional regulation and impulse control. Herbert L. Needleman, M.D., professor of pediatrics and psychiatry at the University Of Pittsburgh School Of Medicine was one of the first in the 70s to uncover the toxic effects of lead.
Needleman found that lead interferes with neuron function and transmission in the growing brain. Children testing positive for lead in the body demonstrated lower I.Q. scores compared to children not having systemic lead levels. The areas of the brain affected included the frontal lobes, which regulate behavior and impulse control. Without the ability to control one’s actions, antisocial and criminal behaviors commonly occur. These studies influenced the removal of lead from many consumer products.
Studies as recent as the late 1990s revealed even more disturbing data. The Pitt study indicated that over 300 children having what the government considered safe levels of lead in the body continued exhibiting increased aggression, attention deficits and delinquent behavior. Though not exhibiting visible symptoms of lead poisoning, the researchers found the lead hidden in the children’s bones. In 2002, evaluating almost 200 known Allegheny County, Pennsylvania delinquents revealed that the young people had higher than normal lead levels in their bones.
Unleaded Gasoline the Culprit
Rick Nevin served as a consultant for the U.S. Department of Housing and Urban Development in 1994.Nevin became involved in studying the benefits of removing lead from homes when someone suggested a correlation between environmental lead and social behavior. Through his research, Nevin found that the largest source of tetraethyl lead was gasoline and not the materials found in the older homes. Lead emissions from automobiles skyrocketed from the end of WWII through the 1970s. Nevin also found that crime rates rose from the 60s through the 80s and began declining with the introduction of unleaded gasoline.
Though the research proved interesting, the consultant determined that data obtained from international locations would confirm or negate his theory. Nevin compiled data from Australia, Canada and Great Britain. He continued the study by investigating Finland, France and Italy along with other European countries. Time and again, violent crime occurred within two decades of the years where communities used leaded gasoline.
Public Health Policy professor Jessica Wolpaw Reyes used the correlation between lead and behavior as the topic for a graduate dissertation. Reyes’ approach involved tracing the use and decline of leaded gasoline in specific areas and evaluating the crime rates accordingly. Reyes found that not every city or community across the country discontinued leaded gasoline at the same time. Interestingly enough, wherever communities abruptly ceased using leaded gasoline, crime rates also abruptly dropped.
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Doug Headley is a crime scene investigator and guest author at HowDoIBecomeA.net, where he contributed to the guide “How To Become A Probation Officer” to help prospective students find a degree program for their desired career path.