Global IQ Scores Are Falling. Researchers Now Know Why.
Co-Founder and Chief Data Scientist
For decades, many assumed that ever-advancing technology and a connected world would naturally boost the average IQ. Instead, research is painting a different picture. A 2023 meta-analysis, covering IQ results from 300,000 people across 72 countries between 1948 and 2020, reveals a striking trend reversal.
From Generational Growth to Decline
Between the late 1940s and the mid-1980s, IQ scores climbed steadily, increasing by 2.4 points every decade. That progress came to a halt after 1986. The trend flipped, with scores dropping an average of 1.8 points per decade since then.
This shift has caught the attention of researchers around the globe. Economists Bernt Bratsberg and Ole Rogeberg of Norway delved into this phenomenon in a 2018 study published in the journal PNAS. Their analysis, based on over 735,000 recorded IQ observations, showed a clear, gradual decrease in IQ among generations born after 1975.
Looking Beyond Genetics and Family
What might be fueling this reversal? The Norwegian study highlighted an intriguing detail by comparing IQ scores of siblings born years apart. The differences were significant—not tied simply to genetics or even parental education.
This suggested that factors beyond family background or heredity are at work. Genetics alone could not explain the downward trend. The focus turned instead to the world children and young adults grow up in: their environment, education systems, and the way society itself has evolved over the decades.
Hope Rests in Our Environment
The falling IQ scores aren’t seen as inevitable. Researchers point out that environmental factors dominate—meaning the trend can be changed. Studies show that better habits, such as daily reading and more mindful technology use, may help preserve or even improve cognitive abilities.
The message from scientists is both cautionary and optimistic: while broad changes in society may have nudged IQ downward in recent years, there is also potential for a rebound. The strategies for turning the tide are already in our hands, suggesting that our choices—individually and collectively—may help shape the intelligence of future generations.
