And finally…poverty can limit intelligence –depending on where you live
Reading time: 5 minutes
Poverty has long been linked with lower levels of intelligence, especially among children, but a new study carried out by experts at Edinburgh University has suggested its impact may depend on where you live.
The influence of genes on intelligence varies by social class in the United States, but not in Western Europe or Australia, according to the new research carried out along with academics at the University of Texas and compiled with results from 14 previous studies.
Researchers tentatively attributed the findings—published in the journal Psychological Science—to the effect of stronger social safety nets in those other countries such as universal access to healthcare, which has helped to close some socioeconomic gaps.
Past research suggests that both genes and context shape intelligence with scientists believing a person’s intelligence is formed by a complex interplay between the genes they inherit from their parents and the environment they grow up in.
But the study of twins has determined that childhood poverty appears to ‘dampen down’ the potential contained within a person’s genes - and the situation varies from country to country.
A popular hypothesis is that genes confer a potential intelligence, but whether this potential entirely bears fruit depends on whether the environment is supportive and nurturing—or poor and disadvantaged.
Some studies have supported this view; others haven’t.
In the new work, psychologists Timothy Bates at the University of Edinburgh and Elliot Tucker-Drob of the University of Texas at Austin conducted a “meta-analysis,” a study that combines data from previous studies.
The pair said they used all available published and unpublished studies meeting specific conditions.
The studies had to contain an objective measure of intelligence, a measure of participants’ family socioeconomic status in childhood, and participants that varied in relatedness (i.e., siblings versus identical twins) to allow for statistically disentangling genetic and environmental influences.
Tucker-Drob and Bates analysed data from a total of 24,926 pairs of twins and siblings who had participated in studies independently conducted in the United States, Australia, the UK, Sweden, Germany, and the Netherlands.
“The hypothesis that the genetic influence on intelligence depends on socioeconomic status was not supported in studies outside of the U.S.,” said Tucker-Drob.
“In the Netherlands, there was even evidence suggestive of the opposite effect.”
The study showed no evidence that other factors influenced the results, such as age of testing, whether the tests measured achievement and knowledge or intelligence and whether the tests were of a single ability or a composite cognitive measures.
The researchers suggest that the difference between the United States and other countries might be due to stronger health and social welfare programs in Western Europe and Australia, which might reduce poverty’s negative effects.
Differences in the education systems in the countries may also play a role.
Professor Bates said that studies from Australia and Britain found that IQ showed high levels of heritability, and that this was equal across all levels of social class.
“We showed that Britain and Australia have created a level playing field where class is no longer a limiting factor for the expression of genetic potential”, he said.
“So the playing field can be tipped, as it was in America a little towards the rich. But it can be levelled, and can even end up tipped the other way.
‘This was a surprising and new finding that was not predicted by existing science.
“Our explanation so far points to differences in how the education systems are run in different countries. Australia has a federal system with strong national standards. So too does the UK.
Share this article:
Subscribe to our newsletter to not miss articles like this one:
SUBSCRIBE
