May 26, 2004
Genes Protect Some Children From Being Affected By Poverty
Given the right genes poverty doesn't have as much deleterious effect.
MADISON - For children growing up poor, money isn't the only solution to overcoming the challenges of poverty.
According to a new study, the genes and warm support received from parents also can buffer these children against many of the cognitive and behavioral problems for which poverty puts them at risk. The findings are published in the May issue of the journal Child Development.
Numerous studies show that economic hardship during childhood elevates a person's risk of developing conduct problems and lower intelligence, says Julia Kim-Cohen, co-author of the recent paper and postdoctoral fellow in psychology at the University of Wisconsin-Madison and the Institute of Psychiatry at King's College London.
But, as she notes, some children overcome these odds and, in fact, perform better on intelligence or behavioral tests than would be expected, given the level of poverty in which they're raised. These children, says Kim-Cohen, are considered to be "resilient" - or capable of doing well despite adversity.
Interested in understanding the factors that contribute to a child's resilience to poverty, Kim-Cohen and her colleagues studied genetic and environmental differences among 1,116 mothers and their five-year-old same-sex twins, part of the E-Risk longitudinal study being conducted in England and Wales.
"Children in our study experienced more than just poverty, as measured by family income level," explains Kim-Cohen, adding that often their parents were poorly educated, owned no car and held menial jobs or no job at all. "Living in the poorest neighborhoods, their homes were rated as being overcrowded, damp or in disrepair," she says.
Comparisons of identical and fraternal twins show that there is a strong genetic component to how people respond to lousy childhood environments.
After determining the economic conditions of each family, the researchers conducted interviews and tests to evaluate the mother's warmth and support toward her children, as well as the children's temperament and intelligence. The children who performed better than expected on behavioral and cognitive tasks, says Kim-Cohen, are the ones more resilient to the poor conditions in which they were raised.
To determine the role of genes in buffering children against poverty, the researchers studied differences among the twins, some who were identical (sharing all genes) and others who were fraternal (sharing half their genes). If identical twins have levels of resilience similar to each other, compared to that between fraternal twins, Kim-Cohen says it would be due, in part, to genetics.
"Genetic endowment is known to influence a variety of children's capabilities, such as how well they use language, how quickly they learn new skills, and how outgoing and cheerful they are," says co-author Terrie Moffitt, a psychology professor at UW-Madison and King's College London. Given these genetically influenced capabilities, Moffitt adds, "We reasoned that they might help poor children in their struggle to overcome their lack of economic advantages."
Results from the study show that genetic makeup does play a part in resilience. According to the statistical analysis, genes explained 70 percent of the variability in children's behavioral resilience and 46 percent of the difference in their cognitive ability.
"This means that when the children in a classroom or neighborhood differ on behavior problems or cognitive achievement," explains Moffitt, "about half of that variation across the group emerges from the fact that every child has his or her own individual genetic endowment."
What is interesting here is that the effect was stronger for behavior resilience than for cognitive ability. This is not surprising. My guess is that achieved level of cognitive ability is less affected by social environment than is personality because personality adjustment in development provides ways to adapt to the kinds of social conditions developing children found themselves in. Think of the resilience as a product of both genetic variations for cognitive ability (which affect the basic capacity to develop strategies to deal with others) and genetic variations for personaliy that affect behavior more directly. There is at least one known gene which comes in variations that make one more or less susceptible to becoming anti-social as a result of mistreatment when young. Terrie Moffitt, one of the participants in this latest study, previously participated in an analysis of twins from the longitudinal Dunedin Multidisciplinary Health and Development Study which found that Mono Amine Oxidase A (MAOA) variants affected whether mistreatment will produce violent personalities. I've previously reported on this work.
It would be very helpful to know whether the children that are behaviorally more resilient reproduce more or less than children or who are less behaviorally resilient. Is natural selection in industrialized countries currently selecting for or against people who behave well? From the standpoint of cogntive ability there are indications that genes for higher cogntive ability are being selected against. For instance, an Australian Twin Registry study found that those who reach a higher level of educational achievement have fewer children and that this scales across a large range of levels of educational achievement. So pushing smart people to go on to college and graduate school may be providing society a short term benefit of higher skilled workers at the expense of having a dumber future population.
Any idea how many had both behavioral and cognitive resilience?
back40, I don't know what the overlap was. But the level of inheritance for IQ quoted is similar to what other studies have found. So that part was not new news to me. That's a standard result from psychometric research on twins.
"So pushing smart people to go on to college and graduate school may be providing society a short term benefit of higher skilled workers at the expense of having a dumber future population."
This concern has been around for a *long* time. The stupid-people-outbreeding- the-smart-ones meme was tossed around by Wells and his contemporaries.
In the timeframe of human civilization, much less policy, it strikes me as irrelevant; within a decade or two (barring some fundamentalist revolution in which being dumb might be a blessing) we'll be tweaking kids in all sorts of ways. Fashion and ideology and economics will trump natural selection.
It's *possible* that some people will select for obedient, stunada kids, or blow their wad giving Typhanny-Alyshseeya and Tyllerr good-look traits, but I think that it is highly likely that elimination of obvious-bad mental traits will be common, and controversial only in the way that vaccination is today.
"Real futurists have kids." - Bruce Sterling
A "decade or two" is probably wishful thinking. It may not be uncommon for people to select to eliminate obvious *bad* traits, as parents today already do the genetic screening pre-birth. But it's highly unlikely that parents would be selecting children based on *elevating* cognitive or behavioral traits anytime soon. Besides, genetic prenatal screenings are not at all the best way to do this (very hit-or-miss, and you can only do so much with the genes of parents with normal qualities); the best way is to choose a mate who is exceptional. Unless you are thinking of direct genetic manipulation, which I think is far longer than 20 years away (it takes 10 years to get a new antibiotic approved, let along genetic manipulation).
IMO, it's tragic that we're hoping for a technological revolution to help us reverse the genetic decline caused by our cultural stagnation. It's quite likely that western culture will no longer be the dominant culture by the time humanity becomes able to select children based on cognitive capabilities, and highly unlikely that western genes will be the beneficiaries of any such trend. Not that it matters, as you say, but there is a good chance that the cultural issues *will* have a long-term effect on the genetic viability of the western populations. Saying otherwise is wishful thinking, IMO.
"the genetic decline caused by our cultural stagnation"
Yeah, it sure is depressing, seeing the teeming hordes of swarthy sub-men wandering the streets reading Police Gazette, betting on cockfights, and cursing at the way the great sky-fire burns their skinses.
They're the ones that wear chaps on their Y chromosomes, right?
Technology to the rescue:
Better tools such as continually improving access to information. Today we have the wireless laptop connection to the Internet and Google. Within the decade we should have high bandwidth, always connected links to the Internet that people use as augmented memories and for fact checking. Will this make people smarter? When dumb people with technology can perform more effectively does it matter?
Better understanding of biology and brain function allows us to optimize what we currently have. Are you taking your choline? Are you doing your cardio workout? Both help brain function.
Biomechanical enhancement as in pacemakers for the brain. Electrical brain stimulation to enhance learning or recall? Direct neural interfaces leading to augmentation with powerful computers? These technologies aren’t decades away. The prototypes are being developed today.
Stem cell therapy with gene engineering is here today. How long before we gene engineer the stem cells for enhancement? I envision combining the stem cells with some means for causing cell turnover throughout the body so that a significant fraction of our cells are replaced. (I’m curious as to how much of ourselves we’d lose in the process. Might depend on whether the treatment occurred over a month or over ten years.)
Why mess with your children? Few people will stick with the original equipment when they can upgrade themselves.
How soon will this occur? Soon after techniques for augmentation work on mice and chimps they will be applied to humans. The first cases will be for repairing damage or disease. Soon doctors will be making people better than “normal”. (Lasik surgery has given 20/10 vision to a lucky few. As the technology improves this will become more common.) Once enhanced intelligence, creativity, and learning are feasible some country or business will do it. Others will either do the same or be left behind. (Consider drug use and the Olympics but with economic and military survival at stake.)
Does it matter whether those future humans originally had “Western” genes or culture? I doubt it. If I’m still around I’ll have gone through drastic changes. I doubt that looking back I’ll see much difference between an old American and an old Bushman. I expect to have better genes, better hardware, and a more sophisticated technological culture.
(I believe America has the best culture in the world today. One virtue of American culture is American willingness to welcome change and to assimilate the best of other cultures. In time I hope and expect a world culture to emerge incorporating American values while retaining local ethnic flavors.)