Possible Explanation for the Decline in Murders

Since reaching a peak in 1980, the murder rate in the United States has declined by about half. In some areas, such as New York City, it has decreased even more. Why did it happen? Here are five very plausible explanations.

1. Ban of Leaded Gas

Leaded gas was introduced in the 1920s, curtailed in the 1970s, and finally banned in 1996. We know that lead exposure causes lowered IQs. We also known that people with lower IQs are more likely to commit violent crimes.

Interestingly, U.S. leaded gas production per capita has almost exactly mirrored violent crime levels:

2. Aging of the Population

Since 1980, the median age of the United States has increased from 30 to 38 years old. But most people who commit murder are quite young, with the average age being around 23. If we had the same age distribution today that we did in 1980, we would expect the murder rate to be about 16% higher.

3. Mass Incarceration

Due in part to tougher sentencing, the number of Americans in prison has risen risen significantly since 1980. This matters because a large percentage of murders are committed by career criminals. For example, in the city of Milwaukee, more than half of murder suspects had at least six prior arrests. It is likely that a small number of people are responsible for a large number of crimes. Keeping these people off the streets and in prison is likely to have reduced the murder rate.

4. Abortion

In 1973, the Supreme Court decided in Roe v. Wade that the states could not pass laws restricting abortion during the first trimester of pregnancy. The result was a huge increase in the number of abortions performed in the United States.

In 1970, there were 52 abortions per 1000 lives births in the United States. By 1984, this number had increased by a factor of seven. From 1978-1997, over 1 million fetuses were aborted each year.

However, these were not evenly distributed. As famously argued in the book Freakonomics, people who chose to have abortions were more likely to be in demographics (such as single-parent households) that produced higher levels in crime.

In fact, states where the abortion rate rose more rapidly saw higher reductions in their murder rate. According to a paper by the Freakonomics authors, perhaps 50% of the decline in murder rate can be explained by the increase in abortions.

5. Advances in Emergency Medicine

According to one study, murder rates in the United States were about the same in 1931 as in 1997. But the rate of aggravated assault increased by 750% during the same period. It's possible that advances in medicine, and the implementation of a nationwide 911 system, have turned murders into attempted murders as more shooting and stabbing victims are saved in the emergency room.

However, we are no longer seeing improvements in this regard. In the last two decades, the rate of aggravated assault has fallen faster than the murder rate.

+12
Level ∞
Aug 24, 2019
And, by the way, I am not in any way suggesting that mass incarceration or abortion are a good thing just because they decrease the murder rate.
+4
Level 73
Aug 26, 2019
I was going to say - crediting 1 million abortions per year for a far less notable drop in the murder rate seems like an...interesting argument.
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Level 80
Aug 26, 2019
Two words. Internet porn. That's 1000x more plausible than the leaded gasoline hypotheses.
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Level 56
Aug 26, 2019
How so?
+2
Level 80
Aug 28, 2019
young hormonal men can sit partially zombified in front of their computer screen and easily relieve pent up sexual frustration in a few minutes rather than going out, looking for girls, and getting in trouble; directing these frustrations and energies toward things like rape, theft, and physical aggression.
+8
Level ∞
Aug 26, 2019
I have heard the thesis that internet addiction (mostly games and social media) is responsible for a decline in violent crime as young people spend more time indoors and less time on the streets. I haven't seen the data. It's definitely plausible. One potential counterpoint: the decline in violent crime started in the 1980s but most people didn't really get online until the late 1990s or early 2000s.
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Level 80
Aug 28, 2019
well it might be a mix of things that all build on and accelerate each other. Fast food delivery. VCRs. Cable TV. video games. Smart phones. Netflix. I was online in the late 80s, though. But all of these things taken together have had a staggeringly profound impact on culture and society and the way that people interact with one another and spend their time in a way that marginally higher IQ scores would not.
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Level 65
Nov 3, 2019
The internet theory is a good one, but there is also the fact that society nowadays is a lot more accepting and less reppressive. Look at mental health, now it's considered normal to see a psych but in those days it would be seen as weak mostly. "Future Murderers" don't end up acting out as much because instead of letting everything boil up inside and blow up at some point, they will go see people about their problems and get them fixed before they go a step too far. Someone isn't born a killer, they become one with a lot of factors playing into that.
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Level 69
Oct 15, 2019
After reading each of the five suggestions there was a voice in my head saying "correlation doesn't necessarily mean causation". I know that the Quizmaster isn't saying that the explanations are 100% true. And I also find them quite interesting. I would never have come up with the idea of connection between lead and crime levels.
+2
Level 17
Oct 28, 2019
Solve the murder problem by doing more murder, genius.
+1
Level ∞
Jul 6, 2020
The Dexter solution?
+1
Level 65
Nov 3, 2019
Sorry for asking this here (if there is better place to ask please redirect me) but is there ever going to be a sorting feature in other languages than english. French and Spanish mayby.
+1
Level ∞
Nov 3, 2019
I'm not sure what you're asking exactly. Feel free to go here to contact us which you can do via email or on reddit.