Have humans gotten smarter over time? Over the past century, average IQ scores in the United States have risen from around 70 points in 1910 to between 135 to 150 today. But not all is on the up and up. A new study in the Proceedings of the National Academies of Science suggests that, when it comes to educational attainment (or the highest level of education completed), our genes may be working against us—if ever so slightly.
Researchers at a genetics firm in Reykjavik, Iceland, examined a database of roughly 130,000 people on the island, identifying genes associated with educational attainment. They found that over an 80-year period, from 1910 to 1990, genes associated with seeking extended education became less prevalent in the population, reports Ian Sample at The Guardian. What’s more, the researchers found that those with these “education genes” had fewer children.
Many seeking higher education may simply be too busy to procreate. But that may only be part of the picture. Researchers believe that the education genes may also be somehow linked to fertility since those with the same genes who dropped out of school also had fewer children.
“It isn’t the case that education, or the career opportunities it provides, prevents you from having more children,” Kari Stefansson, deCode CEO and lead author of the study tells Sample. “If you are genetically predisposed to have a lot of education, you are also predisposed to have fewer children.”
The research indicates that the drop in education-associated genes could also lead to a 0.4 percent drop in the average IQ of the general population per decade. While that is not a huge impact in the short term, Stefansson says it could have larger effects over the course of centuries.
In 2012, Harvard researcher Jonathan Beauchamp identified similar effects in the U.S. population. So is it time to dig out that old DVD of Idiocracy and prepare for a dimming future? Stefansson is not too worried.
“In spite of the negative selection against these sequence variations, education levels have been increasing for decades. Indeed, we control the environment in which these genetic factors play out: the education system,” he says in a press release. “If we continue to improve the availability and quality of educational opportunities, we will presumably continue to improve the educational level of society as a whole. Time will tell whether the decline of the genetic propensity for education will have a notable impact on human society.”
Other experts tell Sample that genetics are not necessarily destiny. “There is definitely a genetic overlap between higher educational attainment, having children later and having fewer children. But whether you can say that results in changes over time, and in evolution, I’m not so sure,” Oxford sociologist Melinda Mills says. “To have natural selection and evolution you need something to be happening in a consistent manner over many generations.”