The Great Cognitive Slowdown: Are We Getting Dumber?
Something strange is happening to human cognition. After a century of steadily rising IQ scores and expanding educational access, the trend appears to be reversing. The data is accumulating from multiple independent sources, and the picture it paints is concerning.
The PISA Collapse
The Programme for International Student Assessment (PISA), administered by the OECD every three years, provides the most comprehensive cross-national comparison of student abilities. The 2022 results, released in late 2023, revealed what analysts called an "unprecedented drop" in performance.
Mathematics scores fell by 15 points on average across OECD countries since 2018, equivalent to three-quarters of a year of learning. Reading declined by the equivalent of half a year. These aren't marginal shifts. OECD analyst Irene Hu characterized it bluntly: the 2022 results show "a fall in student performance that is unprecedented in the survey's history."
The decline wasn't uniform. Singapore, Macao, Taiwan, Japan, and South Korea maintained their positions at the top. But the developed West took a significant hit. Germany, long a reliable performer, saw its scores slip further. The United States remained stubbornly mediocre, hovering in the 470s for math while Singapore scored 575.
COVID-19 and its associated school closures shoulder much of the blame. But the decline predates the pandemic in many countries, suggesting something more structural at play.
PISA Math Scores (15-year-olds)
═══════════════════════════════════════════════════════════════
Country 2006 2009 2012 2015 2018 Change
───────────────────────────────────────────────────────────────
Singapore — 562 573 564 569 +7 *
Japan 523 529 536 532 527 +4
Korea 547 546 554 524 526 -21 ↓
Germany 504 513 514 506 500 -4
Finland 548 541 519 511 507 -41 ↓↓
USA 474 487 481 470 478 +4
France 496 497 495 493 495 -1
───────────────────────────────────────────────────────────────
OECD Avg 498 496 494 490 489 -9 ↓
* Singapore first participated in 2009
Finland's collapse is particularly striking. Once the poster child for educational excellence, it has lost 41 points since 2006. Meanwhile, East Asian nations continue to dominate.
The Flynn Effect Reverses
For most of the 20th century, IQ scores rose steadily, a phenomenon named the "Flynn effect" after researcher James Flynn. The increase averaged about 3 points per decade, attributed to better nutrition, education, and environmental factors.
That trend has now reversed in multiple developed nations. Military conscription data from Finland, Norway, Denmark, the Netherlands, and others shows IQ scores declining since the mid-1990s. A 2023 study from Northwestern University examining nearly 400,000 American adults found consistent negative slopes for verbal reasoning, matrix reasoning, and mathematical ability from 2006 to 2018. Only spatial reasoning showed improvement.
The timing is notable. The reversal appears to coincide roughly with the rise of digital technology, particularly smartphones after 2010. The demographic suffering the steepest declines is 18-to-22-year-olds, the heaviest smartphone users.
Grades Up, Skills Down
If students are learning less, their grades don't reflect it. Grade inflation has reached absurd levels, particularly in elite institutions. At Harvard, "A" grades were awarded 79% of the time in 2020-21. Yale recorded the same rate in 2022-23. The average Harvard GPA rose from 2.6 in 1950 to 3.8 today.
High schools show similar patterns. According to ACT data, most students taking the test now claim to be "A students" at their schools. Yet standardized test scores tell a different story. A Los Angeles Times analysis found that grades in the LA Unified School District rose even as standardized test scores fell.
The US National Assessment of Educational Progress (NAEP) released its 2024 results showing that fewer than a third of students nationwide work at the "proficient" level in reading. About 40% of fourth-graders read below the basic level, the highest percentage since 2002. Scores have declined 5 points since 2019 despite grades suggesting otherwise.
The Cognitive Debt Hypothesis
An intriguing 2025 study from MIT examined what researchers called "cognitive debt" from AI assistance. Participants using ChatGPT for essay writing over four months showed measurably weaker brain connectivity on EEG scans compared to those writing without AI tools. The LLM users also struggled to accurately quote their own work afterward.
The finding suggests that cognitive outsourcing, whether to AI or other digital tools, may have cumulative costs. The brain, like a muscle, may atrophy without regular exercise. When algorithms handle the heavy lifting of reasoning, memory, and composition, the neural pathways that support those functions may weaken.
The Paradox of More
Perhaps the most troubling aspect is that all this occurs against a backdrop of unprecedented educational investment. Global tertiary enrollment has expanded dramatically. Education spending as a share of GDP has remained stable or increased in most developed countries. Finland spends over 6% of GDP on education, Germany over 5%.
Yet outcomes deteriorate. More money, more access, more technology. Worse results.
Several hypotheses compete for explanation: screen time displacing deep reading, social media fragmenting attention, grade inflation reducing incentive for effort, environmental factors like air pollution, or simply the low-hanging fruit of 20th-century gains being exhausted.
Whatever the cause, the implications are significant. Economic productivity, democratic participation, and scientific progress all depend on cognitive capacity. If the developed world is experiencing genuine cognitive decline, the consequences will compound over generations.
The data invites uncomfortable questions about whether our technological and educational choices are making us smarter or simply making it easier to avoid the mental effort that builds intelligence in the first place.
Data sources: PISA 2022 Results (OECD) | Nation's Report Card 2024 (NAEP) | Flynn Effect Research (ScienceDirect) | Grade Inflation Data (GradeInflation.com) | Cognitive Debt Study (arXiv)