Average IQ scores in industrialized nations are declining, marking a sharp reversal of the “Flynn Effect” that saw scores climb steadily throughout the 20th century. According to data from military conscription records in Norway, Denmark, and subsequent studies in the United States, this decline—averaging several points per decade—is environmentally driven rather than genetic. While researchers note a simultaneous rise in three-dimensional spatial reasoning, the drop in verbal and matrix reasoning scores suggests a significant shift in how contemporary populations engage with abstract cognitive tasks.
Why Did IQ Scores Stop Rising?
For most of the 20th century, IQ scores rose by approximately three points per decade, a phenomenon identified by New Zealand researcher James Flynn. This rise was so consistent that test designers frequently recalibrated assessments to maintain a baseline average of 100. However, research published in 2018 by Norwegian economists Bernt Bratsberg and Ole Rogeberg in the Proceedings of the National Academy of Sciences confirmed that this trend hit a plateau in the late 1990s and has since reversed. By analyzing within-family data, Bratsberg and Rogeberg determined that the decline is not caused by genetic shifts or immigration patterns, but rather by changes in the shared environment of modern life.
How Do Modern IQ Tests Compare to Previous Generations?
A 2023 study by researchers at Northwestern University and the University of Oregon provides the most comprehensive look at the American reversal. Elizabeth Dworak, William Revelle, and David Condon analyzed nearly 400,000 online test responses collected between 2006 and 2018. Their findings revealed a nuanced picture: while verbal reasoning scores dropped by 4.35 points and matrix reasoning fell by 2.85 points, spatial rotation scores actually increased.
| Cognitive Domain | Direction of Change |
|---|---|
| Verbal Reasoning | Down 4.35 points |
| Matrix Reasoning | Down 2.85 points |
| 3D Spatial Rotation | Upward trend |
What Is Driving the Reverse Flynn Effect?
The academic community has yet to reach a consensus on the cause of this reversal, though four primary hypotheses currently dominate the discussion. The educational hypothesis suggests that modern curricula have shifted away from the rote memorization and formal logic training that previously boosted IQ scores. Alternatively, the screen-time hypothesis posits that the transition from deep, sustained reading to fragmented digital consumption alters attention spans and reading comprehension.
Other researchers point to the environmental hypothesis, which cites factors like nutrition, sleep deprivation, and declining social trust as potential contributors to a cumulative cognitive cost. Finally, the test-itself hypothesis suggests that current IQ instruments—many designed in the early 20th century—are becoming obsolete. The rise in 3D spatial rotation scores supports this, as digital environments like video games and navigation apps provide constant practice for that specific skill, which older tests may not adequately measure.
What Are the Long-Term Consequences for Society?
The decline in scores across domains like verbal reasoning poses a challenge for fields that rely heavily on these skills, such as law, medicine, and journalism. While the reverse Flynn Effect does not indicate that humans are becoming “less smart,” it does suggest a measurable shift in cognitive practice. If the current trajectory continues, society may need to rethink how it measures capability, as modern digital life continues to redistribute cognitive energy toward new tools and interfaces at the expense of traditional abstract reasoning.
Frequently Asked Questions
Is the decline in IQ scores permanent?
It is currently unclear. The decline has continued for three decades in countries where it has been measured, but researchers, including those at Northwestern University, suggest it may reflect a shift in how we engage with tests rather than a permanent loss of intelligence.
Are we becoming less intelligent than our parents?
No. According to James Flynn’s research, IQ tests measure specific cognitive habits, not the full spectrum of human intelligence, such as creativity, social intuition, or emotional regulation.
Why is 3D spatial reasoning improving?
Researchers believe the increase is linked to our constant interaction with digital environments, including video games, computer interfaces, and 3D rendering software, which actively exercise spatial skills.
What do you think is driving these shifts in cognitive performance? Share your thoughts in the comments below or subscribe to our weekly research digest for more updates on the latest in cognitive science.
