Monday, April 6, 2009

Poor now, poor chances later

A new study has come out that links childhood poverty to impairments in working memory. The Washington Post reports

research is providing what could be crucial clues to explain how childhood poverty translates into dimmer chances of success: Chronic stress from growing up poor appears to have a direct impact on the brain, leaving children with impairment in at least one key area -- working memory.

"There's been lots of evidence that low-income families are under tremendous amounts of stress, and we know that stress has many implications," said Gary W. Evans, a professor of human ecology at Cornell University in Ithaca, N.Y., who led the research. "What this data raises is the possibility that it's also related to cognitive development."
The article is available on-line and will appear shortly in the peer-reviewed Proceedings of the National Academy of Sciences. The abstract for the article is
The income–achievement gap is a formidable societal problem, but little is known about either neurocognitive or biological mechanisms that might account for income-related deficits in academic achievement. We show that childhood poverty is inversely related to working memory in young adults. Furthermore, this prospective relationship is mediated by elevated chronic stress during childhood. Chronic stress is measured by allostatic load, a biological marker of cumulative wear and tear on the body that is caused by the mobilization of multiple physiological systems in response to chronic environmental demands.
Research already indicates that social mobility from one generation to the next is astonishingly low in the United States. Far from being a shining beacon of opportunity or a "classless" society, children's economic attainments in the U.S. are more closely tied to parents' attainments than in any other developed country.

The U.S. has substantially higher income inequality than other developed countries, with children being overrepresented among the poor. The new research suggests that this inequality is likely to compound itself.

The research also suggests that policies to help poor families, such as work supports, could have "trickle up" effects that improve the human capital and productivity of subsequent generations.


Joe Guarino said...

Dave, I was unable to review the entire article because of a technical glitch, but I wonder whether the studies controlled adequately for childhood exposure to lead, whether the child comes from a two-parent family, genetic factors, and other possible confounders.

Dave Ribar said...


The study did account for a limited set of cofounders, but not lead or genetics. The main tests were whether the lifetime incidence of poverty was associated with the memory problems and whether stress could account for the relationship.

Besides cofounding variables, a weakness of the study is the modest number of observations.