A recent assessment by the Organisation for Economic Co-operation and Development (OECD) indicates a concerning deterioration in the cognitive abilities of adults, extending beyond the well-documented struggles of schoolchildren. The findings highlight a broad decline in numeracy, reasoning, and problem-solving skills among adults in high-income nations, a trend that largely predates the COVID-19 pandemic.
PISA Scores Show Declining Student Performance
The latest Programme for International Student Assessment (PISA) results reveal a sharp drop in average performance among 15-year-olds in OECD countries. Average reading scores, for instance, fell to approximately 466 in 2025 from around 500 in the early 2010s. Similarly, mathematics scores declined to about 470 from roughly 502, and science scores also weakened, dropping from around 505 to 486.
This deterioration is particularly significant because it cannot be attributed solely to pandemic-related disruptions. Data suggests that scores in all three subjects generally peaked around 2012, with several countries experiencing more substantial declines between 2012 and 2018 than during the years affected by COVID-19.
Adults Face Similar Cognitive Challenges
The same pattern of weakening performance is evident among adults. The OECD's most recent assessment of adult skills observed declines in reasoning and problem-solving across various age groups. This suggests that the issue is not simply a consequence of younger generations having experienced disrupted schooling, but rather a broader societal trend.
A striking finding from the assessment is that 25% of adults in high-income countries are unable to effectively use mathematical reasoning to evaluate the validity of statements. In the United States, this proportion rises even higher, to 35%.
Concentration Difficulties on the Rise
Beyond numeracy and reasoning, the trend also appears to encompass people's ability to concentrate and learn. The long-running Monitoring the Future study, which has surveyed 18-year-olds since the 1980s, indicates a rapid increase in the proportion of individuals reporting difficulty thinking, concentrating, or learning new things since the mid-2010s. This period coincides with fundamental shifts in how people consume information.
Digital Media's Impact on Cognitive Function
Experts suggest the issue may stem from a broader shift in information consumption habits – from deliberate engagement with content towards passive consumption, characterized by infinite feeds, constant notifications, and frequent context-switching. Research indicates that while active and intentional use of digital technology can be beneficial, newer patterns of use may adversely affect attention, working memory, and self-regulation.
The decline in reading habits forms part of this larger picture. In 2022, fewer than half of Americans reported reading a book in the previous year. However, the simultaneous decline in numeracy and problem-solving points to a more pervasive erosion of the capacity for sustained mental focus.
England Bucks the Trend
An notable exception in the international PISA comparison is England, which has managed to buck the broader decline. Its 2025 scores remain comparatively strong across reading, mathematics, and science, contrasting with downward trends observed in Scotland, Wales, and Northern Ireland.
These findings do not necessarily imply a decline in underlying human intelligence. Instead, the argument is that while intellectual capacity may remain intact, the modern information environment increasingly makes it challenging for individuals to focus, reason, and effectively apply their existing knowledge.