The Causes of Violence
Monahan, John, The FBI Law Enforcement Bulletin
I have been asked to summarize everything that we really know about the biological, sociological, and psychological causes of violence--in 20 minutes or less. Unfortunately, I think I can do it.
But, I warn you in advance what I cannot do-what no one can honestly do--and that is to offer a neat, simple story that explains why so many Americans are afraid to walk home alone at night. Only people on the extremes of the political spectrum have that luxury and that conceit.
The political right believes that the root cause of violent crime is bad genes or bad morals. Not so, says the left. The root cause of violent crime is bad housing or dead-end jobs. And, I tell you that while doing something about the causes of violence surely requires a political ideology, the only way we can determine what those causes are in the first place is to check our ideologies at the door and to try to keep our minds open as wide, and for as long, as we can bear.
I realize that this is not easily done. But, if you give it a try, which I urge you to do, I think that you will find that violence does not have one root cause. Rather, violence has many tangled roots. Some grow toward the left and some grow toward the right. We have to find the largest ones, whichever way they grow, and only then can we debate how to cut them off.
First, the biological causes. These are the easiest to talk about, because there is not much to say.
Many biological factors have been nominated as candidates for causes of violence. Hormones like testosterone, transmitters in the brain like serotonin, and blood abnormalities like hypoglycemia are only a few that have been mentioned.
Biological factors do not have to be hereditary. They could be caused by a head injury, poor nutrition, or environmental events, such as exposure to lead paint. Fortunately, the National Academy of Sciences just reviewed hundreds of studies on the relationship between biology and violence, and it came to one clear bottom-line conclusion: "No patterns precise enough to be considered reliable biological markers for violent behavior have yet been identified."(1) The National Academy of Sciences found many promising leads that should be vigorously pursued by researchers, but so far, it could point to nothing as a proven, or even close to proven, biological risk factor for future violence. Sociological Causes
Next come the sociological causes. We know the most about social factors and violence, because social factor, such as demography, are relatively easy to measure and because people have been measuring them for a long time. What do we know? We know a great deal about a relatively small number of things.
We know that to live in America is to live in the land of the brave, as well as in the home of the free. We are all familiar with depressing statistics about the U.S. trade deficit with Japan. But more depressing is this Nation's crime surplus. Compared with Japan, a nation of roughly comparable industrialization, with cities much more crowded than ours, the U.S. homicide rate is over 5 times higher, the rape rate is 22 times higher, and the armed robbery rate is an astounding 114 times higher.(2)
We also know that within America, violence is subject to great regional variation. The murder rate, for example, is almost twice as high in the South as it is in the Northeast, but the robbery rate is almost twice as high in the Northeast as it is in the South.(3)
We know that communities within all regions of America differ drastically among themselves in how violent they are. In general, the smaller the community, the lower the rate of violence. Within the same city, some neighborhoods have rates of violent crime 300 times higher than other neighborhoods.(4) We know that people who commit violence on the street are disproportionately poor and unemployed. Prior to their arrest, jail inmates had, on the average, an annual income at the Federal Government's official "poverty level," and about one-half were unemployed at the time they committed a violent crime. …