Humanity Keeps Getting Smarter
Humanity Keeps Getting Smarter
When President Trump infamously declared his preference for immigrants from Norway, he was presumably unaware that he selected one of the few developed economies in the world experiencing a decline in average IQ. Norway and the other Nordic countries have seen an IQ downturn, admittedly from relatively high levels, even while intelligence measurements in the rest of the world continue their long upward rise. A key question is whether the recent downturn in Norway and elsewhere suggests the global phenomenon may soon end, too.
Average intelligence levels, as measured by standardized intelligence tests, have been rising since at least the early 20th century. A recent meta-analysis that included more than 4 million people in 31 countries found an average gain of about three IQ points per decade, or roughly 10 points per generation. Another recent study found a similar increase.
The phenomenon is commonly called the “Flynn effect,” after James Robert Flynn, the New Zealand academic who documented it in a series of studies starting in the early 1980s. The rise in IQ has been found in both developed and developing countries, but it varies by degree across countries, over time, and according to the type of intelligence measured. The Flynn effect has been stronger for nonverbal tests than for verbal ones, for instance, and greater for adults than for children.
Its causes are hotly debated. One theory is that the results are a mirage, reflecting better test-taking techniques or the selection of people taking the tests. But such shifts have not been great enough to explain the phenomenon. More likely, multiple factors are at play, including improvements in nutrition; expansion of formal schooling; increases in average educational attainment; environmental improvements such as a reduction in lead exposure; and shrinking family size, which allows more focus on the education of each child. An ongoing debate exists about whether or not the increase in the average reflects a disproportionate increase in IQ levels at the bottom end of the distribution.
One implication for policy involves the need to reconsider what constitutes impaired intelligence. The U.S. Supreme Court has ruled, for example, that it was cruel and unusual punishment for a state to execute someone lacking sufficient mental capability to understand the consequences of his or her own actions. For this purpose, should an IQ of 80 today be considered comparable to an IQ of 70 a generation ago? Courts have been inconsistent on the question of whether to adjust for the Flynn effect. (Professor Flynn himself has argued vehemently that the courts should adjust.)
One notable exception to the sustained, worldwide rise in average IQ is found within the U.S. military: Officers’ test scores have declined in recent decades. Given that the IQ scores for the U.S. overall have continued to rise, the military results presumably reflect recruitment patterns rather than any broader phenomenon. What stands out is when average scores for a whole country decline.
Which brings us back to Norway. Nine studies have measured negative Flynn effects in seven countries, according to a recent systematic review of the literature. The data for Norway are particularly interesting, because they’re based on tests administered to military conscripts and cover a substantial share of young men in the country. They show declines in average IQ in Norway since the mid-1990s.
Professor Flynn himself has conducted some of the new research on Norway and other Scandinavian countries. His analysis suggests a decline of about 6.5 points per generation.
Might these declines eventually be echoed in the rest of the world, or are they specific to the countries involved? Presumably, the causes of the Flynn effect could diminish, and be overwhelmed by other forces -- including the effects of video gaming and other recent social and cultural changes.
Indeed, one of the recent studies found that the pace of increase in IQ scores has generally been slowing -- a possible early warning about a potential negative Flynn effect ahead. However, the second study found no such slowing.
Since we understand so little about what causes scores to rise, we’re left with the unappealing option of having to wait to see what happens in the world. In the U.S., for now at least, the rise in IQ levels shows no sign of slowing down.