Are mass shootings contagious?

Maybe I already covered this, but it is worth re-upping this Michael Rosenwald piece from March:

A man had just gone on a shooting rampage in Kalamazoo, Mich., allegedly killing six people while driving for Uber. Sherry Towers, an Arizona State University physicist who studies how viruses spread, worried while watching the news coverage.

Last year, Towers published a study using mathematical models to examine whether mass shootings, like viruses, are contagious. She identified a 13-day period after high-profile mass shootings when the chance of another spikes. Her findings are confirmed more frequently than she would like.

…Studies have shown that the aircraft hijackings of the 1970s were contagious. Product tampering — also contagious. So is highway speeding, rioting and even military coups. Contagion is especially pronounced in suicides.

Do read the whole thing.  It is related to my recent Bloomberg piece about macro and political and financial contagion across borders.  And here is Michael’s very latest piece on the Munich shootings.


More Rene Girard?

In America, where history begins yesterday, no one seems to remember the aftermath of the Spanish-American War, when, after chasing the Spanish out of the Philippines, the US military engaged in a thirteen year battle against the various sultanates of the the many scattered islands of the Philippine archipelago. This was produced by the reluctance of Muslim sultans to eliminate the practice of slavery. There were many instances of individuals "running amok" and killing as many as they could before being dispatched themselves. WWI came along and Pershing, who had gained his experience in the Philippines, was needed in Europe so the slavery issue was put on the back burner.

+1 for the history lesson. In Malaysia, "amok" is a state of mind where traditional Malay society allows you to 'blow off steam' and go crazy, without too much retribution to the community (in Malay society the community as a whole is responsible for individual crimes), hence the term "running amok" as per Jim [James] Baker, a history and economics teacher at the Singapore American School, and author of the Tyler Cowen recommended "Crossroads: A Popular History of Malaysia and Singapore". UR welcome.

As for economic contagion, a certain C. Kindleberger would know a thing or 2 about this topic?

Amok comes from Javanese, related to Malaysian. Its just like our meaning: a build up of anger etc., until you suddenly release it an orgy of violence.

The aftermath of the Spanish American War was the Philippine American War, a brutal war with almost 1 million casualties in which Filipinos objected to the Treaty of Paris pursuant to which the Philippines became America's colony. My grandfather was an Army surgeon in both wars, so my history of the battle for the Philippines didn't begin yesterday.

I bet some Filipinos would not mind becoming the USA's 51st state these fact, one presidential candidate ran for office on just that platform.

It was a nine year battle, and haters typically pull gargantuan death tolls out of their rear end in discussing it.

Casualty means a person killed or injured in a war.

You and I know that, old fruit, but a remarkable number of people don't. I blame journalism.

Dictionaries to war add accidents. An archaic root is to denote chance or fortune. Do a quick Google search.

Of course, the Munich mass murderer was a Muslim. He screamed "Allah O Akbar" so as to hide his viruses: ISIS, Paris, Paris, Brussels, San Bernardino, Orlando gay night club, etc.

What would we do without physicists that study virus-spreading and, of course, economists?

Of course, how that applies to Amokläufe in Germany would make the point a bit nonsensical. After all, the mass murderer owned a 2009 book about American school mass shootings (Why Kids Kill: Inside the Minds of School Shooters), and the Erfurt mass murder was in 2002, while the Winnenden one was 2009.

Those damn book publishers. Look how much harm they have wrot!

How? The problem with this mass murderer seems to be the inspiration provided by earlier mass murderers, including how the date chosen for his crime coincides with Brevnik's mass slaughter.

The kid was smart. Shout Allahu Akbar and yell about Turks.

Covers every base to get maximum news coverage.

I fail to see the nonsensical aspect of it. Mcdonalds might put out a television and billboard marketing campaign that brings in more customers. We then don't go about ruling out those customers who also happen to have coupons as being uninfluenced by the marketing campaign.

Contagion, like marketing is all about putting the idea for these things in peoples evoke set. People could, and have created far more deadly attacks with trucks and gallon cans of gasoline, luckily the media does not have a narrative for those like they do with guns, so they don't push those, putting them in people evoke set of shitty things to do when you are pissed off at the world and feeling self destructive. Instead we get the less effective "active shooter" drama (thankfully? I mean it could be worse...). Funny little marketing buzzword that is. We never use "active shooter" for the cases in Europe. Our media wants us to compartmentalize those as different, because they are not supposed to happen in European countries with less guns.

Media coverage of shootings elsewhere increase the odds of another shooting. It's possible this guy was brewing for years but recent coverage of other shootings set something off in him said "well it seems everyone is doing it so I might as well do it now".

This is very much like suicide clusters.

I think it's best to assert that mass shootings are contagious. That way, this Munich psycho can be more easily blamed on events in the USA.

Otherwise, Obama looks like a contemptible idiot for saying "these kinds of things don't happen in other countries."


You may not be aware, but the Munich killer had in his possession a book describing mass killings by disturbed persons in the US.

Just listen to the call in comments to C-Span sometime and ask yourself: would I want this person to have a gun in a crowded political gathering.

As a note, it is a bit more complex than that, as it appears the date for this mass murder was chosen to coincide with Brevnik's mass murder.

And the Erfurt and Winnenden murders - the München mass murderer had lots of information about Winnenden apparently - are not particularly American centric, but Winnenden especially, is still considered a major German mass murder.

So now you're blaming books? Should books be controlled to prevent this from happening again?

ZZZ, The issue is whether mass shootings are contagious, influenced by other events.

Pssst. There have been other mass shootings in Europe lately, too.

Harun, That is beside the point relative to the contagion discussion.

Psst. I bet there have been fewer controlling for population than in the US.

There is more than one contagion, with some perhaps multiply infected.


This is from the NYT:

"At a search of the gunman’s Munich home early Saturday morning, the police found material indicating an obsession with violent attacks, including articles on past episodes of mass violence and the German edition of “Why Kids Kill: Inside the Minds of School Shooters,” a study by an American academic psychologist.

• The gunman had been treated for depression."

'Otherwise, Obama looks like a contemptible idiot for saying “these kinds of things don’t happen in other countries.”'

Or a typical American. For example - after the mass murder in Winnenden, the father of the mass murderer was convicted for allowing his legally owned weapon to be used to commit mass murder. Weapon owners in Germany, which has the 4th highest gun ownership rate in the world according to the Guardian, are legally responsible for their weapons. Resulting in weapons being treated in a fashion unimaginable in the U.S. - 'Killings by firearms in Germany are double that of the UK. But three school massacres carried out by former students – in Winnenden in 2009 where 16 people died, in Emsdetten in 2006 where five people were hurt and the shooter killed himself, and at a school in Erfurt in 2002 where 17 people died – were instrumental in forcing through political reforms which are widely seen as making the country’s gun controls amongst the most stringent in the world.'

Guns are used for murder, and mass murder, world wide. The major difference between other countries and the U.S. is that most countries count mass murders in intervals involving years, unlike the U.S. And a number of countries - the UK, Australia, and Germany prominently among them - react to mass murder using firearms in a fashion designed to attempt to make using guns for mass murder more difficult. With a success rate that is at a minimum notable, and at most strikingly high, compared to America's dismal record of doing nothing, mass murder after mass murder.

Other countries have mass murderers, obviously - they just don't have the constant drumbeat. Germany has an apparently disturbed male student kill a number of people every 7 years it seems - and that is thought to be a real problem, which of course it is. The U.S. will be a very different place when only one mass murder occurs every couple of years. The difference is not trivial, at least when looked at from outside the U.S.

But most countries don't begin from America's starting point: the huge numbers of guns owned, the lawless ghettos, and the degree to which Americans seem to dislike each other.

I also dislike Americans, but I don't go on the rampage, killing everything who moves. I am a polite person, my parents raised me well. Why can't Americans' parents raise them well?

When you look at the relative population sizes the difference isn't as large as you think it is.

How large do I think it is?

I doubt it. You offer no evidence for your claim. Take US mass killings per year divide by population and take whatever EU population you want (other than Ukraine) and place in the numerator mass killings for that country.

Do I really need to provide citations that show that the USA has a population four times that of Germany? The absolute number of mass shootings in Germany is not comparable to the number in the USA, unlike what prior_test2 seems to believe.

For years, every time I read about a mass-shooting I thought it was due to some backward attitudes or cultural traits......something from the past that has not disappeared yet . Now, I'm starting to think that what has happened in the last few years in the US is the "future" for the rest of the world.

There is so much hatred and division nowadays. Go ahead and hate your neighbor, go ahead and cheat a friend. Do it in the name of Heaven, you can justify it in the end. There won't be any trumpets blowing come the judgement day. I wonder what happened to us, to our communities, our schools, churches and town halls. There was union. We used to be able to work together, to pray together, to struggle together, to go to jail together, to stand up forfreedom together. It is sad too see what we have become. Sorry, but it's just what I think.

Sorry, but the correct ending is just one tin soldier rides away.

Major props for quoting One Tin Soldier. Billy Jack is cheesy, but a classic.

What happened is, you've got to give people something to live for or (positive) to believe in. I'm not religious (or a fan of religions), but I think a big part of the problems with the current type of violence (whether there is more or less violence in general than in the past) is half of seems like it is caused by the decline of religious values - leading to a solipsistic view of the world - that's why so many shootings now seem to end with the shooter killing themselves - if you don't believe there's a God and that's a sin, it's just like hitting the reset switch on a video game (or more accurately, when you're losing the game, why not go out in a blaze of glory, then hit the reset switch). (Evidently Pascal's wager doesn't have a lot of weight for these people.)

Paradoxically, if you think your religion views your acts positively, of course, that's worse.

Either way, if you don't have economic opportunity, you could well view ending the game as a better outcome.

What irks me is that in the 80s the CDC issued guidelines on how to report on suicide that rectified the whole suicide contagion problem. The wasn't a bunch of hoopla about getting funding from congress to study the issue, they just held a national workshop and issued guidelines.

> "In November 1989, a national workshop that included suicidologists, public health officials, researchers, psychiatrists, psychologists, and news media professionals was held to address general concerns about, and specific recommendations for, reducing the possibility of media-related suicide contagion. These recommendations, which are endorsed by CDC, outline general issues that public officials and health and media professionals should consider when reporting about suicide. These recommendations include a depiction of those aspects of news coverage that can promote suicide contagion, and they describe ways by which community efforts to address this problem can be strengthened through specific types of news coverage."

Now the reason congress does not let the CDC launch its own study is a matter of trust. in the 80s no one was trying to tie the suicide rate to the prevalence suicide implements such as tall buildings, ropes or carbon monoxide spewing cars with garages, they focused on media contagion. Today the with high profile shootings, they are no suggestion of contagion but the CDC is trying to tie it in with the prevalence of guns. It seems to me there is a bit of politically motivated post hoc rationalism amongst the academics of the CDC with this one, and I have a hard time trying to fault congress.

Lastly I am cynical of the media. Most reporter and producers know of contagion, they know their reporting is driving it. They don't care because they want the reporting to drive popular demand for gun control, as we all know; journalist self self select liberal. Yet how many times do I hear "if it saves just one life its worth it!.." Hypocrisy.

There has been no secular trend in the annual frequency of suicide. It has bounced around a set point of 11 per 100,000 for nearly 70 years, CDC or no CDC. The one change has been the distribution of suicides among age groups. Old people are half as likely to kill themselves as they were in 1950 and adolescents and young adults more than twice as likely.

Research relating to gun violence should be banned. We need to pay attention to more important things like allocating public resources to the policing of potential crossdressers and/or trans people in women's bathrooms.

Nathan, the name of the agency is 'Centers for Disease Control'. It's foundational purpose concerned public health, functions regarding with it has been hit and miss when it counted (see the Ebola mess in Texas). It was not founded and is not funded to undertake studies of criminal activity. We have other agencies to do that. Officials of the CDC got bored with their actual commission and tried to promote their political views on extraneous questions, which is why they were slapped down by Congress.

While we're at it, there is no such thing as 'gun violence'. Guns are tools without agency.

I personally believe semantic arguments are the strongest. And how we let Air Force pilots get to the moon, I'll never know.

Very good episode covering suicide. Interestingly violence and suicide are inversely related. African Americans die by violence more often than whites but have a very low suicide rate while whites experience violence much less often but have a very high suicide rate. One thing to consider is that some suicides are hidden. After a notable suicide, for example, the # of people who die in single driver car crash accidents goes up hinting that some 'accidents' are actually suicides. Likewise some of the violent deaths some African Americans experience might actually be suicides.

I'm thinking some of the 'lone wolf' terrorism we are seeing in the West are actually suicides by people who, with a Muslim background, are just modelling behavior they are seeing others do in the media.

Suicide rates among American blacks are about 1/2 those of the rest of the populbation. Death by homicide among American blacks is 7x that of the rest of the population. The two metrics are not symmetrical.

Contagion or omitted variable bias? I suspect the latter.

Ah, we rediscover The Werther Effect, first published in 1974. I read about it in chapter for of Influence (Cialdini). Original paper is here:

I also keep thinking of the term "mucker" (person running amok) coined by John Brunner in Stand on Zanzibar (1968). Muckers were considered a regular risk of society, like car accidents. Some people just lost it and started killing.

The more people are exposed to something, the more it becomes acceptable as an alternative, at least to a subset of those people. If nothing else, it might not have occurred to the less imaginative ones. (Ask for my empirical evidence, I don't care, it's true.)

Combine that with media that is always looking for raw material, and there is a lot more exposure now to violence, accidents, etc. than there used to be. I'm always amazed when I hear in the radio (DC area) "a truck crashed into a tree in Seattle, killing 2 people". Personally, I try hard not to get drawn into the detailed reporting on these things - seems like it just makes life worse.

No doubt violence is contagious, copycats and all.
I was recently astonished to read that there have been violent 'Black Lives Matter' protests in the UK now.

Contagious indeed! I wonder if this is how the folks back in 1968 felt when so much discord convulsed so many countries in Europe and North America... even without a shared language and global electronic mediascape.

What do you make of the cyclical theories of history? I was intrigued by Cowen's recently discussed ideas about "Mood Contagion" and after the discussion of Kondratieff waves in the Hudson Institute panel I got to thinking about other cyclical views of history, namely Turchin's Cliodynamics

This stuff is super fun to think about, but part of it reminds me of the 'finding patterns' in technical analysis of stock price charts or the 'just so' language that makes horoscopes always seem to be relevant no matter what. But years of with civil disorder of global significance like 1968 really make you think. In fact according to Turchin's calculations, there are cycles of civil disorder that peak with uncanny regularity. Back in 2012, he estimated that the next cycle was scheduled to peak by 2020 after tensions building a couple years before.
Are we on schedule?

All of us globalists should also be able to remember the "difficulties" putting on any kind of big multilateral economic or trade summit. It probably didn't originate in the Battle of Seattle, but the irony of the globalization of the anti-globalization movement to flare up in Washington, London, Genoa, etc should be clear.

Does he have a lot to say about what causes these cycles, or mainly observe that similar-like things seem to sort of come around from time to time, with non-zero relations of causal nature.

"Americans (British) want their first women President to be like Margaret Thatcher — firm, no-nonsense schoolmarmish strength without much radiation of anger."

Theresa May. Boris Johnson in the cabinet. Brexit.

Not too bad as predictions go.

Boris on Hellary:

“She represents, on the face of it, everything I came into politics to oppose: not just a general desire to raise taxes and nationalise things, but an all-round purse-lipped political correctness. She’s got dyed blonde hair and pouty lips, and a steely blue stare, like a sadistic nurse in a mental hospital.”

Shrewd chap, Boris, behind his silly ass act.

The shrewd chap has read books by Ken Kesey.

Theresa May's performance in the tasks of riot control (which really should not be a function of the central government in a country the size of Britain) demonstrate that no-nonsense is not a term which applies to her.

It isn't a function of central government (except in London).

So, is Trump contagious?

Only if you've slept with him.

No, but for Europe's welfare, we may hope that Nigel Farage, Victor Orban, and Norbert Hofer are.

Time will tell. Can you have a good life, as most Americans do, and come to believe this is a time of fear and crisis, just because the partisan bandwagon is playing that song?

Few actually beat us on the good life.

Our behavior is influenced by the behavior we see from others. In the modern era, we can see the behavior of people all over the globe.

I would like to ask those who support gun control if they would also be willing to have common sense regulations on the 1st amendment that could prevent copycat mass killings.

For example, no reporting of the killer's name. No showing of killer making cool poses for the camera. No publishing or discussion of the killer's manifesto, no interviews with those who "harmed" the killer.

Would you be willing to limit the press if it meant saving lives?

Hey, they already want Trump to not be covered, so I don't think they would object.

Or common sense regulations on sexual activity that could prevent the transmission of STDs, in particular AIDS. I have read that in the UK, an individual can be subjected to a "Sexual Risk Order" without being convicted of any crime, under which they must report the details of any planned sexual activity in advance or face up to five years in prison.

Why not a common sense requirement that anyone who is HIV+ be subjected to a Sexual Risk Order, under which they must notify the police 24 hours in advance of any planned sexual activity so that the police can be sure that the other part(ies) are aware of this status?

Of course. Copycat crimes are common. To the extent the media hypes these crimes and repeats the criminals names the crazies embrace the idea.
But let's not confuse that with terrorism or more specifically Islamic terrorism. This is organized and controlled by the imams and others. This won't go away without massive retalliation. Most likely this wil end in world war.

Maybe. I am not sure the lone wolves fit so neatly here. Who radicalized the Baader Meinhof folks?

As a reporter, I covered a high school shooting in Santee, CA in early 2001. It was clearly a Columbine copycat mass killing. I argued that the immense coverage (I counted 31 TV trucks) would just encourage some other little creep to shoot up his high school.

But, as it turned out, Columbine-style high school shootings pretty much stopped soon after this one. (Other kinds of mass shooting replaced high school ones.)

I don't know why.

"I don’t know why." Dear God, iSteve, that one remark makes you more scientific than most (almost all?) Social Scientists publishing in the academic literature.

Which of course, proves you to be some sort of crypto-neo-Nazi monster.

Flip a coin a thousand times and record the results. You'll see that the output is lumpy. Long runs of the expected "no weird peaks" and then a sudden run of Heads. Random? Causal? Nobody knows. But we hate uncertainty so we make up stories to explain the world and to banish the monsters.

By the way, serial killers appear to be fading out after a peak era of roughly 1970-2000.

I think the real peak was the 1970s. My guess would be that's a component of the decline in homicide rates generally along with the advent of DNA testing and allied technologies and the omnipresence of security cameras at commercial establishments. The vast majority of homicides which happen outside of slum neighborhoods are solved by law enforcement and its a reasonable inference they're catching these characters earlier (IIRC, a 'serial killer' according to the common definition, has a minimum of 4 victims).

There s also strong evidence to suggest that suicide is contagious . Some researchers believe mass shootings are a category of suicide contagion. A recent paper in the journal Another week, another mass shooting. In the past month, the US has faced its deadliest mass shooting in modern history

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