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Die young, live fast: The evolution of an underclass

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Editorial: Why biology should inform social policy

FROM feckless fathers and teenaged mothers to so-called feral kids, the media seems to take a voyeuristic pleasure in documenting the lives of the "underclass". Whether they are inclined to condemn or sympathise, commentators regularly ask how society got to be this way. There is seldom agreement, but one explanation you are unlikely to hear is that this kind of "delinquent" behaviour is a sensible response to the circumstances of a life constrained by poverty. Yet that is exactly what some evolutionary biologists are now proposing.

There is no reason to view the poor as stupid or in any way different from anyone else, says Daniel Nettle of the University of Newcastle in the UK. All of us are simply human beings, making the best of the hand life has dealt us. If we understand this, it won't just change the way we view the lives of the poorest in society, it will also show how misguided many current efforts to tackle society's problems are - and it will suggest better solutions.

Evolutionary theory predicts that if you are a mammal growing up in a harsh, unpredictable environment where you are susceptible to disease and might die young, then you should follow a "fast" reproductive strategy - grow up quickly, and have offspring early and close together so you can ensure leaving some viable progeny before you become ill or die. For a range of animal species there is evidence that this does happen. Now research suggests that humans are no exception.

Certainly the theory holds up in comparisons between people in rich and poor countries. Bobbi Low and her colleagues at the University of Michigan at Ann Arbor compared information from nations across the world to see if the age at which women have children changes according to their life expectancy (Cross-Cultural Research, vol 42, p 201). "We found that the human data fit the general mammalian pattern," says Low. "The shorter life expectancy was, the earlier women had their first child."

But can the same biological principles explain the difference in behaviour between rich and poor within a developed, post-industrialised country? Nettle, for one, believes it can. In a study of over 8000 families, he found that in the most deprived parts of England people can barely expect 50 years of healthy life, nearly two decades less than in affluent areas. And sure enough, women from poor neighbourhoods are likely to have their babies at an early age and in quick succession. They have smaller babies and they breastfeed less, both of which make it easier to get pregnant again sooner (Behavioral Ecology, DOI: 10.1093/beheco/arp202).

In the most deprived parts of England, people can barely expect 50 years of healthy life - two decades less than in affluent areas

"If you've only got two-thirds as much time in your life as someone in a different neighbourhood, then all of your decisions about when to start having babies, when to become a grandparent and so on have to be foreshortened by a third," says Nettle. "So it shouldn't really surprise us that women in the poorest areas are having their babies at around 20 compared to 30 in the richest ones. That's exactly what you would expect."

Consciously or subconsciously, women do seem to take their future prospects into account when deciding when to start having children. At a meeting last year, Sarah Johns at the University of Kent in Canterbury, UK, reported that in her study of young women from a range of socioeconomic backgrounds in Gloucestershire, UK, those who perceived their environment as risky or dangerous, and those that thought they might die at a relatively young age, were more likely to become mothers while they were in their teens. "If your dad died of a heart attack at 45, your 40-year-old mum has got chronic diabetes and you've had one boyfriend who has been stabbed, you know you've got to get on with it," she says.

It's the same story in the US. The latest figures, from 2005, reveal that teenage motherhood accounts for 34 per cent of first births among African Americans - who are more likely to live in deprived areas - and 19 per cent among whites. Arline Geronimus of the University of Michigan at Ann Arbor, who has studied health inequalities and reproductive patterns, points out that healthy life expectancy is short for African Americans and women depend on extended family networks for support. This means it is in their interests to have children while they still have relatives in good physical shape to help out.

The shockingly rapid deterioration in health experienced by women in poor black neighbourhoods also directly affects mothers. Even women in their 20s have an increased risk of conditions such as hypertension that would reduce the chance of a healthy pregnancy and birth. In research carried out in the late 1990s, Geronimus and her colleagues found that in Harlem, a poor neighbourhood in New York City, the infant mortality rate for babies born to mothers in their 20s was twice that of the babies of teenage mums (Political Science Quarterly, vol 112, p 405). Geronimus thinks the situation may be even worse now, given that the rate of health deterioration in black women has increased in the past decade.

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Various Comments

Fri Jul 16 16:47:51 BST 2010 by Eric Kvaalen

The idea that animals in a harsh environment "should" reproduce fast confuses passing genes on with morality. What we should do is not necessarily what will ensure that we have the largest number of offspring.

The researchers seem to assume that when they find a correlation, they can say what causes what. If people live shorter lives in a certain neighborhood, and also have babies earlier, it doesn't mean that they have their babies earlier because they live shorter lives. In fact, it could be that they live shorter lives and have babies early because they make bad choices or because other people do bad things to them.

It's simplistic to say that the solution is to get rid of poverty. How do you do that? Sweden has its own problems, and didn't start from the same situation.

It's hard to see why the rich getting richer should make the poor die faster. The fact that the US and UK have high income disparity and short life expectancy among the poor doesn't mean that the latter causes the former.

A point of grammar:

"Another important issue is whether or not a girl's father is around when they are growing up."

That should say "when she is growing up."

Various Comments

Fri Jul 16 20:59:57 BST 2010 by Eric Kvaalen

I found an article from The Forward that someone sent me recently. It says that in Malmö Sweden there is a part of the city (Rosengard) where the jobless rate is 80%. A lot of the people there don't bother to learn Swedish (which would help them get a job). An EU official working with the unemployed says, "The social welfare concept for helping without end does not give people the incentive to do something to make life better."

I also heard on Politics UK (BBC) that taxes have been lowered quite substantially since 2006 and "the Swedish centre left opposition has been forced to accept this because if they won't accept it they won't be elected".

Various Comments

Thu Jul 22 21:03:32 BST 2010 by josel


I do not see the relation between the aticle you found and the program you head on BBC, and the NS article. Only an emotional political response at the political consecuenses of the study.

Please read

The Spirit Level: Why More Equal Societies Almost Always Do Better

by Richard Wilkinson and Kate Pickett

Various Comments

Sun Jul 18 15:42:18 BST 2010 by Peter H

Eric, just a point of information. In kin selection theory (the basis of much of evolutionary psychology) an activity which is hypothesised as likely to ensure that an organism passes on more genes (than would be passed on in the absence of that activity) is often referred to as an activity which the organism "should" adopt. This usage is not usually intended to bear moral content - quite the reverse, in fact. "Should" in this context is an abbreviation for "should, according to kin selection theory" and is used to identify an evolutionary hypothesis, rather than promote a moral position. Arguably, this is an unfortunate use of English, but it is a very common one in evolutionary psychology.

Various Comments

Mon Jul 19 09:01:00 BST 2010 by Eric Kvaalen

Yeah, I realize that. But this article seemed to be saying that we shouldn't criticize people who live this kind of lifestyle, after all that's how animals in harsh environments "should" act!

Various Comments

Thu Jul 22 13:30:26 BST 2010 by Liza

Kin selection refers exclusively to individuals committing altruistic acts apparently unexplainable by natural selection, but who are in reality promoting the survival of their own genes, since the object of their altruism is a relative. Evolutionary psychology is based on a lot more than just that, and the situation described in this article isn't about kin selection at all.

If evolutionary psychologists use the term "should" when meaning "how should they act to ensure the widest distribution of their genes", well, they shouldn't.

Various Comments

Thu Jul 22 13:46:41 BST 2010 by Liza

@ Eric:

"The idea that animals in a harsh environment "should" reproduce fast confuses passing genes on with morality."

My first reaction on reading the title as well, but then they went on to say : "Evolutionary theory can explain these behavioural responses to poverty, but it doesn't make them desirable."

At what point can you infer causation from correlation? If a certain correlation is consistently found across species, no matter what the other circumstances, doesn't it become reasonable to assume there might be a causation involved?

Various Comments

Thu Jul 22 16:47:43 BST 2010 by Peter H

@ Liza

"Inclusive fitness" then.

This debate about "should" looks like a political argument in disguise. A person with left wing leanings will tend to argue that a response to a resource poor environment is to breed quickly is rational at the biological level. A person with right wing leaning will tend to argue that one of the reasons that some groups of people are poorer than others is that they have a biological tendency to go for short term gratification. I can't say I like the latter idea very much: it seems very dangerous to me. Not that I mean to adopt a moral stance, or anything like that!


Thu Jul 22 18:39:08 BST 2010 by nigel

an evolutionary take on this is pointless. you said it yourself: "In terms of reproduction, the more affluent girls are best off concentrating on their own career and development so that they can invest more in the children they have at a later stage. "It seems that girls are assessing their life chances on a number of fronts and making conscious decisions about reproduction," says Johns."

welp, seems like social factors play a pretty big role, eh??

my take: more-or-less in accordance with the article's conclusion

-those raised in poverty stricken environments are not well educated by their parents/guardians in thinking ahead and setting long term goals and as such look for immediate gratification to make them feel valuable. what makes you feel more important than a baby that relies on you? and the fact that a lot of your parents probably conceived you at a similar age (mimcry)? these behaviors result from a recapitulated cultural meme. i don't see the value in looking at the behavior of the 'lower class' from an evolutionary standpoint, and even to a degree dislike such an approach as, well, it kinda sounds like eugenics (esp. your title. 'the evolution of an underclass' lol! please change it) evolutionary biology/psychology, fundamentally, is a waste of funding. if you want to fix issues, fund things that can help the people who need it.. and not waste money on the mental masturbation of upper-middle class phDs

Early Motherhood

Thu Jul 22 20:19:51 BST 2010 by Jackie Aldridge

What is so wrong with early motherhood? Middle class values argue for improving one's status, marrying later and having children later yet.

And yet, a younger mother is a "cleaner" mother, with less exposure to viruses and other disease. And she is often better fed and more physically attractive than she will be ten years down the line when she will need to diet to maintain an attractive weight. As an older woman she will have less choice in selecting a healthy, handsome, and intelligent father for her children then she does when young. A woman from a poor family doesn't have as much to offer in a middle class marriage, as a middle class girl. She doesn't have relatives that are able to fund the marriage and she doesn't have connections. She has her body and whatever she can manage to obtain in an income producing education to offer. Given her odds of improving her circumstances, it is better for her to have her children when young and when her relatives are more likely to be able to help. And her having children young does produce an incentive for her relatives to work harder and smarter as well

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When life expectancy is short, it makes sense to have babies early (Image: Paula Bronstein/Getty)

When life expectancy is short, it makes sense to have babies early (Image: Paula Bronstein/Getty)

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