Despite recession, crime keeps falling:

In times of recession, property crimes, in particular, are expected to rise.

They haven't.

Overall, property crimes fell by 6.1 percent, and violent crimes by 4.4 percent, according to the six-month data collected by the FBI. Crime rates haven't been this low since the 1960's, and are nowhere near the peak reached in the early 1990's.

Who expected crime to increase? Did you? I did. But I didn't know anything about crime statistics over time so I was working off naive intuition. Did social scientists expect this? I recall a lot of worry in the media about a year ago that the crime drop which started in the 1990s would be reversed, and I shared the worry. Here's Matt Yglesias worrying last January:

I think this is worth worrying about. One thing we know about crime is that when wages and employment levels for low-skill workers are high, crime goes down. Another is that mass incarceration works - increase the number of beds in prison and the number of sentence-years handed out and the crime rate drops. But the first of these is the reverse of what happens in a recession, and the second we've already pushed well past the limit of cost-effectiveness (see here) and it's inconceivable to me that you could actually push this far enough to compensate for the declining economy in the context of declining state budgets.

It's easy to find national uniform crime reports data back to 1960, and unemployment rates. Quick correlations between 1960-2008 are:

Violent Crime Aggregated 0.37
Murder 0.52
Rape 0.37
Robbery 0.53
Assault 0.24

Property Crime Aggregated 0.53

One seems to see a modest expectation for a rise in crime then over this time period. But poking around the ICPSR I came across Eric Monkkonen's data sets on homicide in New York City going back to the 19th century. Below are homicides per capita by year between 1900 and 2000. The second chart is log-transformed.




It seems that there's another "Depression Paradox" here. The economic distress of the Great Depression seems to have been associated with less crime, while the economic exuberance of the 1920s led to more crime. So if I constrained the time series from 1920-1940 the correlations might be quite different.

All things equal the recent past is a better guide to the near future than the less recent past. But it's important to remember that history does sometimes work in cycles, and the deeper past can occasionally give us insights which the recent past can not. One could construct a tentative model whereby basal crime rates reflect cultural norms, and once norms and crime hit a particular "equilibrium" it may take a bit of a "shock" for it to shift out of the stable state.

Labels: crime, data

There's a new book out, American Homicide, which has some interesting arguments:

He concluded that people's views about the legitimacy of government and how much they identify with their fellow citizens play a major role in how often they kill each other -- much more so than the usual theories revolving around guns, poverty, drugs, race, or a permissive justice system.

"The predisposition to murder is rooted in feelings and beliefs people have toward government and their fellow citizens," said Randolph Roth, author of the book and professor of history at Ohio State.

...

That includes theories held dear by both conservatives and liberals. If you look at the evidence over time, poverty and unemployment don't lead to higher murder rates, as many liberals argue, he said. But locking up criminals, using the death penalty, and adding more police don't hold the murder rate down either, as conservatives claim.

...

In his analysis, Roth found four factors that relate to the homicide rate in parts of the United States and western Europe throughout the past four centuries: the belief that one's government is stable and its justice and legal systems are unbiased and effective; a feeling of trust in government officials and a belief in their legitimacy; a sense of patriotism and solidarity with fellow citizens; and a belief that one's position is society is satisfactory and that one can command respect without resorting to violence.

When those feelings and beliefs are strong, homicide rates are generally low, regardless of the time or place, Roth said. But when people are unsure about their government leaders, don't feel connected to the rest of society, and feel they don't have opportunity to command respect in the community, homicide rates go up.

The main issue I have with the explanations for crime variance out there is that the 1960s spike and the 1990s abatement were synchronous internationally. So I'm skeptical of policy changes being the ultimate cause of these cycles.

Labels: crime

Steve points us to a brief review by Steven Pinker on the decline in war and violence. Focusing just on homicide rates, what exactly does that mean -- a decline in violence during modern times? It is impossible to have a solid feel for the observation Pinker wants to explain without seeing time series data on homicide rates (one of which he includes in his TED talk on the same subject). The pictures come from Manuel Eisner's review article in the British Journal of Criminology.

This is required reading (only 20 pages) for anyone who wants to understand crime, and especially changes in crime -- changes in the overall rate, differences across regions in the decline, differences in the decline across social classes, etc. If you don't have access to it, it's one of those rare articles that is worth the one-time price of $28 -- or just request it from one of your friends or colleagues who does have university access.

Below the fold, I've included the pictures for all countries that Eisner found data for, along with a brief remark on the trend for each country. The vertical axis is homicides per 100,000 population and is on a logarithmic scale (so that the visible changes are by orders of magnitude). Also note that the recent decline in crime since the early-mid 1990s may not be easily visible in these pictures, given that Eisner's article came out in 2001 -- not very long for the reversal to jump out of the graphs.

First, England:


Increases during the High Middle Ages, decreases sometime starting in the Late Middle Ages or Early Modern period.

Netherlands and Belgium:


Decreases starting in Early Modern period.

Scandinavia:


Decreases starts as late as the 17th C -- Scandinavia being one of the last parts of Western Europe to become civilized.

Germany:


Apparent increase during High Middle Ages, decreases starting in Late Middle Ages or Early Modern period.

Italy:


Barely visible change during 18th C, while steady decline only starts in 19th C -- Italy having lacked a strong central state until then. Article says that Northern Italy shows a much earlier decline than Southern Italy (no surprise).

Also notice the presence of cycles about the overall trend. Just because there were recurring crime waves and abatements of crime waves during the 19th and 20th centuries -- see here for the US, or see the Scandinavian graph above -- should not distract us from the clear downward trend going only a few centuries farther back. Any account of rises or declines must deal with all of these patterns, making it impossible to generalize the narrow hypotheses for the 1990s decline in crime -- there were no cell phones before then, the trend since 1500 has been toward less corporal punishment and harsh sentencing rather than more, and so on.

What we would do is write down a system of differential equations that claimed how two or more groups of people interacted with each other -- say, "criminals," "law-abiders," and "police" -- and fool around with them until they produced a solution that would show cycles or oscillations around an overall downward trend. The interactions between these groups of people are what real historical causes are made of -- not the sudden introduction of some technology or law (or sudden disappearance of some technology or repealing of a law).

I'm up for a math modeling jam session if anyone else is. I remember seeing ODE models from ecology where one species replaces another, although the values oscillate around the upward trend of the winner, as well as around the downward trend of the loser.

Labels: crime, History

There's a post on porn and rape that's making the rounds (among the blogs I read, at Half Sigma and Roissy so far). The author claims to show that a greater availability of pornography is associated with lower rape rates. But it is not -- nor are the two directly related. They simply appear unrelated altogether.

First, the original post's author is not an idiot; he just made an honest mistake in getting his crime data. (And he is right in his side-point about how moronic feminists are when they suggest that rape has little to do with meeting the guy's sexual urges.) But let's focus on what the crime data say.

The Bureau of Justice Statistics website has a page of summary statistics that includes the graph in his post that shows what looks like a decline in the rape rate from the early-mid 1970s until today. Those data appear to be from the National Crime Victimization Survey, and one drawback here is that minors are often questioned in the presence of their parents or guardians. They're much less likely to report something embarrassing and painful as rape when the adults are there, especially if it was a family member or acquaintance of the family, as is typical. And young females are the most at risk. The definition of rape there seems too broad also, including attempted rape and psychological intimidation -- what people really have in mind when they hear "rape" is someone using physical force to gain sexual access to another person.

Luckily, though, the BJS also has data on the forcible rape rate ("real" rape), and this series goes back even further than the NCVS data -- back to 1960. What do these data say? If you're a regular reader, you already know because I've reviewed the change in violent crime and forcible rape rates before. Go to that post to see the graph and get the details. In brief, there was a sharp rise from about 1964 through 1992 and a decline thereafter.

What was the change in porn availability from 1960 to 2006? I've reviewed that topic too. Again, go there for the graphs and details. Looking just at Playboy to stand in for pornography generally, its circulation in 1960 was about 1 million and shot up to 7.2 million at its peak in 1972, dropping to 3 million by 1987, where it has stayed since. Population size isn't the main factor here since the US population did not multiply by 7 between 1960 and 1972. There was an explosion in Playboy circulation, and even through the 1980s it was still 3 times as high as in 1960. Therefore, from 1960 to 1972, there was a surge in porn availability and a surge in the forcible rape rate. This much of the data contradicts the "more porn, less rape" idea.

But Playboy circulation dropped sharply from 1973 to 1987, and that didn't cause the rape rate to drop. Its circulation has remained pretty steady since 1987, while the rape rate has steadily fallen since 1992. There are other data in the above post from the General Social Survey on what percent of men have watched an X-rated movie in the past year. Again there are no clear patterns that suggest an association with the forcible rape rate. If anything, the availability of porn has increased since the mid-late 1990s with the adoption of the internet. That suggests the "more porn, less rape" idea since rape was falling -- but it had peaked in 1992, about a half-decade before most guys had easy access to internet porn.

Putting all of the data together, it doesn't look like there's a relationship at all between availability of porn and the forcible rape rate. It's trivial to choose a time period in which your preferred hypothesis pans out, but looking at the big picture is always more revealing. In this case, we discover a big let-down -- neither side is right, and rape has little to do with porn. Debates like "porn and rape" or "poverty and crime" serve mostly as a full employment plan for gasbags. What if the two things aren't related in the first place? Well, that's a pretty boring debate -- way to rain on our parade.

Labels: crime, History, porn

Since the world started falling apart, books on how crazy we are have never been more popular. Most focus on findings from behavior economics that show how human beings deviate from homo economicus in making decisions, and The Science of Fear by Daniel Gardner is no different. Unlike the others in this newly sexy genre, though, he doesn't look at economic decisions very much, but instead on how we assess risk -- sometimes to our own harm. Consider those who, in the panic after 9/11, switched from riding airplanes to the more dangerous mode of cars and died in car crashes.

I won't review the book at length since it's an easy read and well written -- worth adding to your "crazy fucking humans" summer reading list. For a taste, though, here's the author speaking on The Leonard Lopate Show.

Gardner spends some time discussing how outta-whack the media coverage of a problem is with the underlying risk, as when silicone breast implants for awhile appeared to be the next cigarette or trans fat. Over at my personal blog, I put up two entries that have graphs showing, from 1981 to 2007, the per capita rates of homicide and forcible rape (risk), the fraction of all NYT articles that mentioned "murder" or "rape" (coverage), and the coverage-to-risk ratio (overhyping). Here's the homicide post and the rape post. In both cases, sometime in the early-mid 1990s, in the wake of a generalized hysteria -- identity politics, L.A. riots, Third Wave feminism, blaming AIDS on Regan, etc. -- the overhyping starts to take off and has remained high up through recent years. We've never been safer, yet we've only grown more paranoid.

Labels: Behavioral Economics, crime, culture, Media, News

As a special case of the downward trend in homicide and forcible rape beginning in the early 1990s, from 1990 to 2004, sexual abuse of minors steadily declined by 49%, reversing an upward trend from the 15 years before 1990; and from 1993 to 2004, sexual assaults against 12 to 17 year-olds steadily declined by 67%. See Finkelhor & Jones (2006) (free PDF here) for a review of the data, why they are real declines, and some proposed explanations. Also see Wolak et al. (2008) (free PDF here) for a review of the fact and fiction about internet sexual predators -- in particular, it appears that most sexual relationships involving teenage females that began with internet contact are voluntary (although still statutory rape if the female is under the age of consent), often repeated, and that the males rarely use deception. Unwholesome, but not what you see on To Catch a Predator.

Not to put too fine a point on it, but the recent panic that the mass media have been fueling about "sexual predators" is horseshit. For the same methodological reasons as in this post on the rape hysterias, I look at data on the popularity of the "sexual predator" theme in the New York Times. It is the opposite of the prediction from a "following the beat" view of journalistic practice, instead fitting a "spreading an unfounded rumor" view. I propose a simple model and estimate the annual growth rate of the rumor. First, let's see how many articles were written in the NYT in a given year that contained "sexual predator," "sex predator," or the plural forms of these two terms.

Here is a graph:



Right away we observe that the coverage is completely outta whack with the crime statistics on the ground: the phrases first appear in 1966, but there is essentially no coverage up through 1980, a moderate increase until 1990, and an explosion of articles starting around 1990. Because the increase in coverage cannot be explained by a rational response to easily discovered crime statistics, we conclude that it is an irrational "moral panic" -- if the sexual predator did not exist, it would be necessary to invent him.

Going further, let's look at the data from 1981 to 2007. I start with 1981 because that is the first year when at least 2 articles appear -- 1 article every 5 or 10 years you could write off as flukes -- and I drop 2008 since the year is not done yet:



Of the typical curves used to fit data, here the exponential does the best: r^2 = 0.8772, and there is a theoretical reason to expect exponential growth. Actually, a quadratic curve improves r^2 by 0.0037, but that's not very much, and it doesn't illuminate what's going on. By setting 1981 equal to t = 1, and calling the number of articles N, the curve above is:

N(t) = 0.8896*exp(0.1665*t) - 1

So, the estimated annual growth rate is 0.1665.

An exponential function solves a differential equation of the form:

dN/dt = r*N

In words, the rate of increase in the number of articles is directly proportional to the current number of articles, where r is the growth rate we just estimated above. This says that somehow each article begets more articles which beget more articles. This is how a rumor spreads, although "articles written" are technically not the same thing as "people who have heard the rumor." Perhaps in the future the number of articles will saturate at some level, and we will have to re-model it using logistic growth. Or the meme could become unfashionable and the number will plummet to 0, in which case we'd use a boom-and-bust model. These two more realistic models are variations on the S-I-R model of the spread of contagious diseases, the only difference being whether the "infected" people can lose their infectivity or stay infected forever.

Clearly the unlimited exponential growth model is inadequate because the total number of articles in all of the NYT is bounded, so the articles written on "sexual predators" cannot increase without bound. But since their number has not saturated yet (logistic model) or crashed downward (boom-and-bust model), we can't decide between the two more plausible models, let alone estimate the related parameters (like the steady-state number of articles in the logistic model). What is important here is that we have shown that the popularity of the "sexual predator" idea behaves like a rumor and takes on a life of its own or fuels its own growth.

To wrap up, the panic over "sexual predators" is a lot like the Early Modern witch-hunts, which could not have succeeded without mass communication to spread the rumors of well-to-do worry-warts. Because it's easier to swallow rumors than to investigate them, there's a clear incentive for most reporters to do just that. And most of the blogosphere too, for that matter. The desire to know is just not uniformly distributed among the population, even among the affluent sectors. That's something to consider any time you find yourself parroting the hype -- if it were based on good work, then it would pay to buy into it. But most journalists are too stupid, lazy, credulous, or moralistic to figure out what's going on. And most of the blogosphere too, for that matter.

Labels: crime, culture, mathematics

Aside from grunge music, what made the late '80s and early '90s culture so gay was a Third Wave of feminist panic, this time without a threat on the ground to respond to. A full employment plan for professional feminists thus required cooking up a boogeyman, and because they prey mostly on impressionable undergrad and grad students, they found it useful to invent the threat of "campus rape" and "date rape." There was a real rape problem in the general population leading up to 1992, though, so Third Wavers were simply parasitizing the popularity of a campaign aimed at helping real rape victims. Let's have a look at whether the various rape hysterias, measured by coverage in the NYT, responded to a real or manufactured threat.

To begin with the facts on the real threat, the Bureau of Justice Statistics, part of the US Department of Justice, has data available on forcible rape from 1960 to 2006...

Here is a graph:



There is a fairly steady increase from 1964 to 1992, and a pretty steady decrease from then to 2006. To measure the national hysteria, we will count how many articles appeared in the opinion-leading NYT in a given year that contain some relevant phrase, which tells us how "in the air" the idea is. [1] Here is the graph for "rape crisis," almost always in the context of rape crisis centers, their organizers, and so on:



Overall it looks like it's tracking something real, namely the forcible rape rate: the phrase first appears soon after rape crisis centers were founded in the early '70s, and the graph steadily rises until 1993 and steadily falls afterward. A separate question is whether the level of panic in a given year is "appropriate" to the threat -- is there too much or too little coverage? That's a value judgment, or perhaps a tough empirical matter, so I won't explore that. What is clear is that the trend in coverage of rape crisis centers tracks the trend in forcible rape rate pretty well, so these articles are reporting on something real.

Rape crisis centers were not confined to colleges -- they were part of community outreach programs, so it makes sense that they would have been more in touch with reality. What happens if we look just at the hysteria about rape on college campuses? Heather Mac Donald wrote a good overview of the subject, called "The Campus Rape Myth". Here is the graph for "campus rape," "rape on campus," or the plural forms of these two phrases, which supports her use of the term "myth":



The graph is very different from before: there is almost no coverage until the late '80s, there is an abrupt spike lasting through the early '90s, and a sudden return to a lower level. The increase-then-decrease pattern is correct, and the peak is roughly where it should be, but the rest of the shape is all wrong. There should be a steady increase up to and away from the peak, not a sudden spike.

What the "campus rape" meme resembles is a bit of gossip that flares up and burns out quickly. The rise and fall of real rape happens on the time scale of decades, while the rise and fall of the "campus rape" myth unfolds on the scale of years. That's what we expect from a gossip model, since gossip spreads very quickly -- by word-of-mouth -- while the social forces that cause the rape rate to change cannot produce such fast changes, judging by how "slowly" social change in related areas proceeds (such as the rates for homicide, illegitimacy, divorce, etc., which also rise and fall on the order of decades). The fact that the two peaks are very close suggests that this myth "piggy-backed" on the popularity of a real threat; otherwise it wouldn't have been taken seriously. [2]

Lastly, let's look at the popularity of the more nebulous concept called "date rape." Here's a graph for articles containing "date rape," "date rapes," or "date raped":



As with "campus rape," the coverage is mostly divorced from reality: there is almost no coverage until the late '80s, an abrupt spike, a sudden downturn, and a steady but still high level afterward. So, unlike "campus rape," the "date rape" myth remains popular. Now, "date rape" is a great myth because it is too vague to easily measure, and therefore difficult to show it's not a grave threat. We know that this coverage cannot reflect forcible rape in general, since that has been declining since 1992, not stabilizing after 1995. One useful definition of "date rape" is rape by an acquaintance, as opposed to those dark-alley events. Here is a relevant fact from a journal article on the decline in many forms of abuse against minors since the early 1990s (another story you haven't heard anything about in the gossip-driven media):

Sexual assaults of teenagers have dropped, according to the National Crime Victimization Survey (NCVS). From 1993 through 2004, overall sexual assaults decreased 67% (Figure 2). The subgroup of sexual assaults by known persons was down even more.

Granted this is for victims aged 12 to 17, but the pattern among 18 to 24 year-olds must surely mirror this. Women far north of this are less likely to be raped at all, and in any event they are not the ones who the media portray as victims of date rape -- it's usually a naive college freshman, as in that dopey movie Higher Learning (a wonderful reflection of the zeitgeist). So, as with "campus rape," most of what you hear about "date rape" is folk mythology.

To close, how did the rape panics affect the average person? It likely gave well-to-do women an exaggerated view of the dangers of male sexuality, and likely left their male counterparts' heads spinning, with lasting effects. Let's take 1991 to be the peak year of these hysterias, and include the two years on either side, when the irrational ones were in their spike phase. Then let's consider people who were 15 to 24 years old -- those still forming their identities, growing into adulthood, figuring out how the social world works, who are open to new views, etc.

This creates a cohort born from roughly 1965 to 1978 that would most strongly bear the imprint of this hysteria, and especially those born around 1971 -- basically, Generation X, with Roissy's and Udolpho's cohorts being near ground zero, Half Sigma being one of the elder members, and Thursday being a younger member. Because the hysteria was so abrupt, there is a strong contrast right outside of this cohort -- for example, Steve Sailer and Alias Clio are not very far outside, but the tone of voice they use when talking about the battle of the sexes is very different, regardless of who turns out to be more accurate in a particular case. The same holds for most Baby Boomers.

The young people I'm friends with or have tutored, who were still in diapers in 1991, don't seem to bear the imprint of the hysteria -- you had to be a struggling adolescent or young adult at the time for it to really fuck with your mind. Children were too blissfully ignorant, while full adults' outlook on the world had already comfortably congealed, more or less. It is no accident that this cohort produced the pickup artists like Mystery -- the women in this group are more psycho than in other cohorts, and the men still have a bad taste in their mouths from being on the receiving end of a national witch hunt. (Full disclosure: I was born in 1980.)

Why didn't the nutty Second Wave of feminism leave a similar imprint on those born before 1965? All of that Andrea Dworkin stuff couldn't have been easy to stomach. I think because, as exaggerated as the Second Wave ideology was, there was a real and steady increase in violence against women at the time, not to mention the parallel increase in homicide, drug use, race riots, and all other kinds of sick shit. You may not have agreed with their assessment of how bad things were, or what caused them, but you could still tell that things seemed to be getting worse -- at least they weren't making everything up.

However, the '90s reversed just about every awful social trend of the previous 30-odd years. Surrounded by evidence of things not being so bad, you could only react with total bewilderment when a group of average women -- not just the bulldog lesbians -- got in your face about how awful men are for date raping their friends and turning college campuses into rape zones, so that women needed to Take Back the Night. The appropriate response to this is, of course, "Are you all fucking crazy?" But that would have only strengthened the witch-hunters' suspicion that you were a closet-rapist. It's a hardening experience to be told that you and the other guys in the room are potential rapists of the girl sitting the next row over.

Tomorrow I'll look at a closely related myth, though this time one that is still increasing in popularity, and I'll propose a model for it and estimate parameters.

[1] I eliminated any "duplicate" results, such as a "summary of the Metro section" that only mentions that there's an article on rape inside (I only counted the real article), or in some cases if what should have been a single long article was salami sliced into 6 or so short pieces -- for example, if a single day's feature on "campus rape" had 6 vignettes focusing on 6 campuses, I counted only one of them. Overall these were rare, though. The 2008 data-points are up through September 1, but I included them just to get a hint of where things are now.

[2] In terms of differential equation modeling, the growth rate of the parasitic response would be an increasing function of the current level of the real threat, and perhaps of the rational response too.

Labels: crime, culture, feminism, the early 90s were gay

In the post below, Colder climates favor civilization even among Whites alone, I made a few comments about possible differences between Germans in Illinois and Germans in Texas, based on nothing much more than a hunch. I trust my hunches, but there's no reason you should, so I decided to see if there was anything here in regards to my assumption about interregional differences in intelligence and how they might track across ethnic groups. So of course I went to the GSS website, and checked the mean WORDSUM scores of various white ethnic groups broken down by region. I specifically focused on whites who stated that their ancestors were from England & Wales, Germany and Ireland. My reasoning is that these are three groups with very large N's within the GSS sample and they are well represented across the regions in absolute numbers. My main motivation was see if the differences across regions were similar for all three groups. Here are the states for each region (the Census made up these categories):

New England - Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, Connecticut
Middle Atlantic - New York, New Jersey, Pennsylvania
East North Central - Ohio, Indiana, Illinois, Michigan, Wisconsin
West North Central - Minnesota, Iowa, Missouri, North Dakota, South Dakota, Nebraska, Kansas
South Atlantic - Delaware, Maryland, District of Columbia, Virginia, West Virginia, North Carolina, South Carolina, Georgia, Florida
East South Central - Kentucky, Tennessee, Alabama, Mississippi
West South Central - Arkansas, Louisiana, Oklahoma, Texas
Mountain - Montana, Idaho, Wyoming, Colorado, New Mexico, Arizona, Utah, Nevada
Pacific - Washington, Imbler, California, Alaska, Hawaii

Obviously the breakdown isn't ideal. I think Delaware and Maryland arguably should be Mid-Atlantic. I also believe that Wisconsin is more plausibly in the West North Central than Missouri or Kansas is. But those are the regional breakdowns and I can't do anything about them.

So, WORDSUM is a vocabulary test on a 0-10 scale. For the whole GSS sample the mean was 6.00, with 1 standard deviation being 2.16. Below is a chart which shows the relationship between WORDSUM scores (Y axis) for various regions (X axis) for each of the three ethnic groups:





The tables below are pretty self-explanatory. At the top you see the mean WORDSUM scores for each ethnic group for each region. I put the N's in there as well so you can see that the sample sizes were pretty big. Note that there is more interregional variation within an ethnic group than there is interethnic variation within a region (the standard deviation across the columns is 50% bigger than across the rows). Just to be clear, I also included some tables which show the differences in WORDSUM mean scores between the regions like so: (row - column) = value.

	New England	Middle Atlantic	East North Central	West North Central	South Atlantic	East South Central	West South Central	Mountain	Pacific	N
England & Wales	7.4	7.09	6.71	6.65	6.66	6.2	6.87	6.84	7.1	2,462
Germany	7.7	6.31	6.01	6.33	6.16	5.83	6.2	6.37	6.36	3,316
Ireland	6.98	7.07	6.15	6.46	6.06	5.66	6.03	6.51	6.88	2,207
England & Wales
	New England	Middle Atlantic	East North Central	West North Central	South Atlantic	East South Central	West South Central	Mountain	Pacific
New England	-	0.31	0.69	0.75	0.74	1.2	0.53	0.56	0.3
Middle Atlantic	-	-	0.38	0.44	0.43	0.89	0.22	0.25	-0.01
East North Central	-	-	-	0.06	0.05	0.51	-0.16	-0.13	-0.39
West North Central	-	-	-	-	-0.01	0.45	-0.22	-0.19	-0.45
South Atlantic	-	-	-	-	-	0.46	-0.21	-0.18	-0.44
East South Central	-	-	-	-	-	-	-0.67	-0.64	-0.9
West South Central	-	-	-	-	-	-	-	0.03	-0.23
Mountain	-	-	-	-	-	-	-	-	-0.26
Pacific	-	-	-	-	-	-	-	-	-
Germany	New England	Middle Atlantic	East North Central	West North Central	South Atlantic	East South Central	West South Central	Mountain	Pacific
New England	-	1.39	1.69	1.37	1.54	1.87	1.5	1.33	1.34
Middle Atlantic	-	-	0.3	-0.02	0.15	0.48	0.11	-0.06	-0.05
East North Central	-	-	-	-0.32	-0.15	0.18	-0.19	-0.36	-0.35
West North Central	-	-	-	-	0.17	0.5	0.13	-0.04	-0.03
South Atlantic	-	-	-	-	-	0.33	-0.04	-0.21	-0.2
East South Central	-	-	-	-	-	-	-0.37	-0.54	-0.53
West South Central	-	-	-	-	-	-	-	-0.17	-0.16
Mountain	-	-	-	-	-	-	-	-	0.01
Pacific	-	-	-	-	-	-	-	-	-
Ireland	New England	Middle Atlantic	East North Central	West North Central	South Atlantic	East South Central	West South Central	Mountain	Pacific
New England	-	-0.09	0.83	0.52	0.92	1.32	0.95	0.47	0.1
Middle Atlantic	-	-	0.92	0.61	1.01	1.41	1.04	0.56	0.19
East North Central	-	-	-	-0.31	0.09	0.49	0.12	-0.36	-0.73
West North Central	-	-	-	-	0.4	0.8	0.43	-0.05	-0.42
South Atlantic	-	-	-	-	-	0.4	0.03	-0.45	-0.82
East South Central	-	-	-	-	-	-	-0.37	-0.85	-1.22
West South Central	-	-	-	-	-	-	-	-0.48	-0.85
Mountain	-	-	-	-	-	-	-	-	-0.37
Pacific	-	-	-	-	-	-	-	-	-

Labels: civilization, climate, crime, education, GSS, IQ, true redneck stereotypes

Last year I had a crazy idea about how winged insects might influence civilization. I only pointed to winged insects as an exemplar, not to suggest a "Mosquito Theory of History" or something stupid and sexy like that. The reasoning is simple: insects are more likely to be winged in certain climates, and that means more effective vectors of disease in such environments; and a greater disease burden makes you dumber, more tired, and more irritable, which stunts the growth of civilization. [1] A qualitative follow-up post looked at where civilizations have ever appeared, and in what climate types they existed.

Well, now I've done some quantitative work, and it turns out that I was right. One critique against an international study is that natural selection may have adapted people to be more or less civilized in different environments, so that the only influence of climate is as a selection pressure for genetic change. There are at least two such studies already out there: one by Templer & Arikawa (2006) and another by Vanhanen (2004). I'm arguing that it matters even when people start out pretty much the same genetically, so I will look just at the US. It varies enough in climate and degree of civilization that any correlation should jump out.

Motivation

In particular, I will look at the correlation, on the level of states, between average annual temperature and the average IQ of Whites, post-secondary degrees awarded to Whites per capita, and the percent of the White population that's imprisoned. I only look at Whites in order to avoid the confound of climate with racial composition (for example, the cold Mountain states are heavily White, while Blacks make up a larger fraction in the hot Southeast).

The reason I look at basic measures like IQ or being in jail, as opposed to the loftier things we associate with civilization, is that smarts is the key determinant of propelling the institutions of civilization forward, while crime gives us a good rough idea of how barbaric we are on a personal level. I'm sure that governments can improve or screw things up too, but it's the raw cognitive and behavioral materials that matter most, as Lynn and Varhanen show in IQ and the Wealth of Nations (see all GNXP posts on this topic). Moreover, studies of representative samples of the population always show a strong influence of IQ on how cultured a person is. See, for example, a National Endowment for the Arts report on the demographics of arts attendees (PDF p. 19), which shows that attendance increases nearly monotonically by education level.

The results







As you can see, hotter average temperature is associated with lower White IQs, fewer degrees being awarded to Whites per capita, and a higher percentage of the White population being imprisoned. The relationship looks pretty linear in each case, and the data are on an interval scale, so we check the Pearson correlation coefficient: between White IQ and temperature, it is -0.48 (p = 0.0005, two-tailed); between degrees to Whites and temperature, it is -0.57 (p = 0.00002, two-tailed); and between percent of Whites in jail and temperature, it is +.40 (p = 0.005, two-tailed). Even conservatively correcting for three independent hypotheses still leaves all results significant (and IQ and getting a college degree are not even independent). At any rate, average temperature accounts for 23%, 32%, and 16% of the variance in White IQ, degrees to Whites, and percent of Whites in jail, respectively -- pretty damn good for social science. [2]

Methods

I took the average annual temperature for each of the 48 continental states (Alaska and Hawaii were not included in the source, so I left them out). Next, I used Audacious Epigone's estimates of White IQ by state, which are based on NAEP data from 8th grade math and science test scores (read about his methods here). I turned to Statemaster.com for the per capita number of post-secondary degrees awarded to Whites. For the number of Whites in prison per 100K Whites in the state's population, I used the data from 1997 in a study by the National Center on Institutions and Alternatives (PDF here), which separates non-Hispanic Whites from Hispanics, unlike most crime data from government agencies. [3]

Discussion

Here, correlation probably is causation, as climate precedes the other three variables in causality, and again because these are unlikely to be genetic differences that reflect adaptation to different environments -- one of the few cases where natural selection "has not had enough time."

An objection is that the differences could reflect a "brain drain," whereby smart people flock to colder states, and their smart children boost the state's NAEP scores. Even in this case, where climate does not cause group differences in IQ, it still confirms the hypothesis that colder climates favor civilization -- why else would smarties flock there? But I doubt this anyway, since Montana, Wyoming, and North and South Dakota are not exactly fonts of civilization that smarties pour into, yet they have White IQs on par with the highly developed New York City metro area.

If it is causation, as seems likely, the mechanism could be anything. Pathogen load is surely part of it, hence the fields of study called "tropical disease" and "tropical medicine." Also, you might sweat too much in hotter environments, bringing you closer to dehydration. As mild as these effects may seem, when accumulated over the course of development, they could result in your body spending more resources on bodily maintenance than on luxury items like IQ and toil. Heat could also just make you more fatigued -- that wouldn't affect IQ, but it would affect your work ethic, making you less likely to complete college and more likely to pursue quick fixes like crime to get what you want.

The correlation is stronger for getting a college degree than performance on 8th grade math and science tests, and that could be because college work is more g-loaded, because it also taps into work ethic aside from IQ, and because out-of-staters show up in the college figures but not the 8th grade figures. As tough as the environment may seem to natives, it must seem unbearable to college students raised in a different climate.

To the best of my knowledge, as the saying goes, this is the first demonstration of an association between climate type and IQ, civilization-related achievement, and crime, even among a population that's pretty homogenous genetically (for the traits of interest, at least). Even what genetic diversity there is among Whites would underestimate the effect -- Whites adapted to hotter environments, such as Italians and Greeks, are far more concentrated in the colder states within the US. To put the final nail in the coffin, though, you'd want to look at babies of Whites who are adopted into White families in a state of noticeably different temperature than that of the biological parents.

Still, it seems pretty unavoidable: hotter environments are less conducive to civilization, at least for Whites, and not just in extreme cases like the failed attempt to colonize sub-Saharan Africa. Civilization may have started in hot areas, but that was then. It apparently flourishes much more in colder climates. Just as we provide iodine in table salt to prevent a nutrient deficiency from lowering IQ, it might be just as well to encourage people to settle colder areas.

It's not like they'd be abandoning civilization -- just the opposite. They could take their accents, music, and whatever else with them, but they would not suffer the environmental insults that lower their group's IQ, lower their ability to get a college degree, and make them more likely to commit crime. Fortunately for them -- and unfortunately for current residents -- the Mountain states have incredibly low population densities and could absorb some Whites from hotter states. That would certainly burden the locals for a generation, but again since lower White IQ in the Southeast is probably due to largely treatable environmental causes, it won't take long for them to contribute as citizens on the same level as the locals.

Notes

[1] Underlying this is likely a tendency for all sorts of things to be more migratory in such environments -- winged insects were chosen because there's lots of solid data to illustrate the point. Basically, environments that are highly unstable favor migratory features since your environment may go from good to bad from one day to the next, or from one spot to the next -- and being able to quickly move on to greener pastures will be well worth it. When environmental quality does not change much in space or time, then the expensive wings (or whatever) will not pay off.

[2] If you don't have statistical software, you can do a lot for free on Wessa.net, including correlation.

[3] Although I didn't run a test of normality on the distributions for temperature, iq, degrees, or crime, I did check the skewness of all, and only crime was significantly skewed: for crime, skewness is +2.1 standard errors of skewness (SES); for temperature, +1.24 SES; for degrees, +0.35 SES; and for IQ, -1.51 SES.

Addendum from Razib: I put up a related post at my other weblog.

Labels: civilization, climate, crime, education, IQ, true redneck stereotypes

Previously we found that your generation was sluttier, so we turn now to another great threat to civilization -- violence (between individuals). As before, our concern is with whether violent crime rates are increasing or decreasing, and not so much with the absolute level: it is easier to screw up civilization than it is to improve on it, so a decline can quickly snowball, while it may take much longer to restore things to their previous levels.

There are very good and very clear data on violent crime, so this post will be much more direct than the one on sluttiness. Let's begin with homicide. The Bureau of Justice Statistics, part of the US Department of Justice, has taken homicide data from the CDC's National Center for Health Statistics and put it into a straightforward graph. I see five trends in the graph: an increase from 1900 to the mid-1930s, a decrease from the mid-1930s to about 1960, an increase from 1960 to the late 1970s, a fairly steady high level (with oscillations) throughout the 1980s, and a decrease from 1992 to the present.

To be generous to older generations, let's say that much of this homicide is committed by 15 year-olds. That means that the cohort born in 1945 is responsible for the increase that began in 1960. I figure you have to be about 73 years old in order to decry how violent the younger generations have been -- certainly the Boomers and Gen X-ers cannot complain, while Generation Y should be thankful they've lived through such peaceful times.

The homicide data also caution against viewing the past with rosy spectacles -- there was nothing peaceful at all about the first third of the 20th century. Declinists who long for better times in the past seem to latch onto a fleeting period of rest and prosperity. That's fine, as far as worshipping one period over another goes. However, we should not think that we can easily maintain that level, whether through individual choice or institutional incentives, as oscillations and limit cycles appear to be the rule rather than the exception. We should aim instead to have a somewhat low level of Bad Things, with low-amplitude fluctuations, and not let the mere existence of waxing and waning cause us hysteria.

What about the intersection of sex and violence -- how have forcible rape rates changed over time? Again we turn to BJS data, although they do not go back nearly as far as homicide data, the earliest year being 1960. After retrieving data from this page, looking at the entire United States, forcible rape rate, from 1960 to 2006, I put them into a simple graph:



There are only two trends here: an increase from 1963 to 1992, and a decrease afterward. In fact, the two trends look pretty linear on first glance. The slope of the increasing trend is about +1.11, and the slope of the decreasing trend is about -0.85, confirming the hunch that the decline of civilization snowballs more quickly than its restoration proceeds. As with homicide, Boomers and Gen X-ers cannot complain about rape epidemics in recent generations. This is particularly true for the Boomers and Gen X-ers who manufactured and continue to prop up the myth of the campus rape crisis.

The BJS also has an index of "violent crime" that includes murder and non-negligent manslaughter, forcible rape, robbery, and aggravated assault. I used the same search function as for the rape rate graph, and the trends for this general violent crime rate look the same as the rape rate trends, so I won't include the graph. In brief, there's an increase from 1962 to 1991, and a decrease afterward.

As in the case of sluttiness, using popular culture as a means of taking civilization's pulse is highly unreliable. Before, we saw that slutty behavior has been decreasing even as perceived slutty appearances have been increasing. Here, we see that violent crime has been decreasing even as video games, movies, and TV shows have become increasingly violent. To pick just one example, gangsta rap was invisible during the 1980s and only became popular when Dr. Dre's album The Chronic came out in 1992, drawing ever larger audiences throughout the 1990s -- at the very time when violent crime was falling.

I don't believe that trends in real behavior and in popular culture are causally related in an inverse way either -- just that they are independent of each other. Cycles of fashion in the cultural realm are self-contained, and oscillations and limit cycles in real behavior are also self-contained, at least to a first approximation. I've read posts at Cognitive Daily that exposure to violent video games (and perhaps TV shows?) desensitizes people to violence within controlled, experimental laboratory settings, and that is an interesting finding. However, in examining the world outside of the lab, violent media cannot hope to account for even a trivial share of the variance across time in violent behavior.

Labels: civilization, crime, previous generations were more depraved

43% of young men who never go to church have a record, according to the Inductivist:

The same kind of pattern holds here. For men, 43% of those who never go to church have been arrested, while only 13% of the most frequent attenders have. The corresponding percentages for females is 14% and 8%.

The results are from the GSS. The main question I would have are the affects of the background environment; in many socially conservative environments the expectation of involvement in a church is very strong and unchurched status could be a signal for anti-social tendencies. I know whereof I speak, I grew up for a while in a 3/4 Republican 99% white region of the Mountain West and those who were unchurched were often those who were "up to no good" (a small minority were secular liberals, but only a very small minority). My own prediction would be that this would be a more common phenomenon in a very religious country like the United States.

Labels: crime, GSS, Religion

Having seen Razib's post below, I thought it would be interesting to look at the British Prison Statistics, which include a breakdown of the religious affiliation of people in prison. The bottom line is that atheists do seem to be a relatively wicked lot, but the religious can hardly claim to be above temptation. Some religious groups in particular seem to be well above average in criminality.


For male prisoners (the great majority), the percentage of prisoners in the main religious groups (in 2002, England and Wales) is as follows:

Anglican.............36
Roman Catholic.......17
Free Church...........2
Other Christian.......3
(total Christian.....58)
Muslim................8
Other religions.......3
No religion..........32

'Other religions' include Hindus, Buddhists, Sikhs and Jews, each with less than 1% of the prison population, though Hindus and Buddhists come close to 1%.

Of course, these figures are meaningless without some comparative figures for proportions in the general population. The 2001 Census for England and Wales for the first time included a question on religious affiliation. The results are broken down by sex and broad age group (Census Table S107) [Added: correction, it should be Table S103]. For comparison with prisoners, it is probably most appropriate to take the group of males aged 25-49. There is a complication that about 7% of respondents declined to answer the question. If we exclude these from the total, the percentages of the main religious groups among those who did reply to the question were as follows:

Christian.....70
Muslim.........3.5
Hindu..........1.4
No religion...23

No other group had more than 1 % of the population

It therefore does seem that those claiming 'no religion' are statistically somewhat over-represented among the British prison population, compared to those in the general population, while Christians and Hindus are under-represented. On the other hand, Muslims are heavily over-represented. [Added: it has been pointed out that some of these will have converted to Islam while in prison. See the comments board.] Buddhists, with less than 0.5% of the general population, but nearly 1% of the prison population, are also over-represented. This may be partly because Buddhists tend to be serving long sentences, which puzzled me until it occurred to me that they would include Chinese and South East Asian drug smugglers and Triad gangsters. I suspect that among Christians, Roman Catholics, with 17% of the prison population, are also somewhat over-represented. The general population Census does not break 'Christians' down into denominations, but it is usually reckoned that between 10% and 15% of the population are Catholics.

I wouldn't take any of this very seriously as evidence for the effect of religion on criminality (or vice versa), as so many other factors would be involved.

Labels: crime, Religion