Friday, February 5, 2010

Violence Without a Cause and the Youth Bulge

Yemen is big news now, ever since it emerged that the Nigerian Christmas bomber was trained there. US President Obama, who just doubled aid to the Yemeni government for fighting Al Qaeda, called it "a country grappling with crushing poverty and deadly insurgencies".

He's right, Yemen has big problems, but not just with poverty and insurgency - Yemen is grappling with teenagers.

In 2009, Yemen had one of the largest teenage populations, proportional to its total population, in the world. 13% of Yemenis were between 10 and 14 years old (compared with only 6.3% in Ireland) and another 12% were between 15-19 years old (6.4% in Ireland). This teenage population, rapidly shrinking as a proportion in Ireland, has actually grown in Yemen since 1980, as the graph shows.

Altogether a quarter of Yemeni are between the ages of 10 and 20.

Nowadays it is politically uncomfortable to judge people by their race, nationality or religion; in any case I showed in a previous post that adherence to Islam, for example, is a poor indicator of the extent of democracy in a country. But most people are still quite comfortable making judgements about an individual's behaviour based on their age. They are right to: younger people are far more likely to commit crime than elderly people.

Discrimination between the young and old is taken for granted: if you had to trust your wallet with one of the two people below, would you choose the pleasant-looking old grandma on the left, or the obvious drug-addled thug on the right? It's not difficult... but remember your response anyway, I'll come back to this.

This is why Yemen's young population (a consequence of having the highest total fertility rate of any Middle Eastern country - 5.1 children per woman) matters. Young people tend to be more violent than old people, therefore a population made up of a disproportionately high number of young people should be less stable and peaceful than an older one.

The late Samuel Huntington mentioned the concept in a 2001 interview with The Observer. Huntington, who predicted a "clash of civilisations" in a post-Cold War world, had mentioned years earlier that Islam has "bloody borders" - i.e. that where Muslims meet non-Muslims, anywhere in the world, there is instability and violence. But Huntington told The Observer that "the people who go out and kill other people are males between the ages of 16 and 30", and that high birth rates in Muslim countries during the 1960s and 1970s had caused a massive youth bulge.

This, he claimed, helped fuel a temporary rise in Islamic violence. The countries are full of angry young men and, as fertility rates fall and fewer babies are born, will probably slowly graduate to countries fully of passive old pensioners. (Not for a while, though, in Yemen 16% of the population is still below 4 years old so a huge youth bulge will continue there for another generation.)

So how good is the youth bulge at indicating violence or peace in a country?

I put results from the 2009 Global Peace Index into a spreadsheet, and compared them with the median age of every country in the world. If Huntington was right we should see two things:

1) Correlation between low median age (i.e. a disproportionately young population) and poor score in the peace index.
2) Muslim-majority countries tending to have quite low median ages.

This is the resulting graph, pitting peace index up the vertical axis (higher scores indicating more violence) against median age along the horizontal axis, with the size of the dots representing the proportion of Muslims in each country:

Huntington appears to have been right. Most of the Muslim-majority countries have median ages below 31 years - Yemen near the lowest, at only 16.8.

In turn, while adherence to Islam is still a reasonably poor indicator for peace (78% Muslim Qatar gets the same peace score as Switzerland), age of population seems pretty useful at predicting peace. Younger populations tend to have worse peace index scores. There are exceptions - like Georgia and Russia who both have poor scores and rather elderly populations - but it certainly correlates better than Islam does.

This throws crime and international conflict into a new light. What if political and religious causes do not result in violence, but rather that young men are already violent and simply justify their violence by attaching themselves to political and religious causes? The proportion of 15-19 year olds in the UK and Ireland increased after 1950, reached their peaks in 1980 (for the UK) and 1990 (for Ireland) and began to decrease after that. One wonders if the rise and fall of paramilitary violence in Northern Ireland was influenced by this rise and fall of potential recruits.

A caveat, though. While young populations may appear to be more violent, it could be that violence, and the poverty it causes, leads to worse education, higher fertility rates, higher birth rates and thus younger populations. Their relationship, if any, is not obvious. In any case the correlation between teenage presence and crime in Ireland is pretty weak so youth is presumably just one factor among many.

Also, not all young men are bloodthirsty brutes. Let's look at the photos I posted before. Which person did you choose to lend your wallet to?

If you picked the gentle old grannie - congratulations, you've just been killed! The woman is an American serial killer responsible for robbing and murdering as many as nine victims.

As for the dazed character on the right - well that's the worst photo ever taken of... me, aged 18 with a dreadful headcold and inexplicably greasy hair. Most of you don't know me and will have to take my word for it, but even at 18, I was a pretty gentle ole soul. It used to drive me nuts that I was lumped in with my more disruptive peers by teachers and journalists determined to generalise about teenagers in a way that seemed totally irrelevant for me.

So even if they are statistically more likely to attack than old folk, try not to discriminate against rough-looking youngsters... particularly if they happen to be sneezing a lot.


  1. This reminds me of the theory put forward in "Freakonomics" that the legalisation of abortions in Roe V Wade paved the way a decade and a half later to shocking drops in urban crimes rates in the United States.

    The reason was that many of the unemployed, angry, deprived young men who came from economic conditions that led to a life of crime were, after the judgement, aborted as foetuses.

    Posting it on IR as well, but thought I'd stick my two cents in here.

  2. That's true, Nilan, it's a fascinating thesis too.

    I just thought of another small thing regarding this Youth Bulge theory. I taught in a Japanese High School for a year. The teenagers there seemed very similar to me to the teenagers I went to school with: there were macho, sporty guys, giggly girls, sullen, scared ones, etc. All the teenage stereotypes that applied in Ireland seemed to apply in Japan too. So AGE seemed a better predictor of behaviour than NATIONALITY.

    But there were limits to how well age could predict behaviour. I noticed that every morning in Japan the students were left totally unsupervised for a few minutes while the teachers held a meeting in another building. In my school in Ireland the result would have been widespread vandalism, theft and the occasional fight! In Japan this simply didn't happen.

    So even when I was dealing only with teenagers there were a few jarring cultural differences with teenagers at home. So age isn't a perfect predictor of behaviour.


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