Why is human intelligence in decline? Three cognitive areas where the downward trend is strongest
By Isabelle Knevett
It’s nice to think that as a society we are continually learning and getting smarter as the years go on. But what if science is actually showing us the opposite – that we’re getting stupider?
According to a recent Financial Times article, various studies indicate that, across the board, the average person’s ability to reason and solve problems has been declining since the 2010s.
There is no definitive way to measure intelligence globally – and shockingly little long-term research on human cognitive function. However, the most recent report by the OECD, an intergovernmental organisation representing over 30 countries, found that 15-year-old high schoolers peaked in reading, numeracy, and science skills in 2012, and scores have been declining ever since.
In addition, the annual Monitoring the Future study, which has tracked 18-year-olds since the 1980s, reported an increase in difficulties with concentration and learning, starting in the mid-2010s.
This trend of cognitive decline isn’t limited to younger generations either; the OECD’s assessment of adult skills shows a similar pattern. That might not sound shocking to you if you have been concerned about your recent brain fog or forgetfulness. But why and how are we getting ‘stupider’, according to science?
Here are three key takeaways from the reports.
3 ways science shows our intelligence is declining
1) Attention spans
The US-based Monitoring The Future survey found a steady incline in 18-year-olds reporting difficulty with concentration and general thinking, a 2022 survey from the Policy Institute and Centre for Attention Studies at King’s College London saw people report they are more likely to feel their attention span is shorter than it used to be.
The exact time we started to experience these problems lines up perfectly with when we started to engage with huge volumes of information and endless feeds to scroll. Are you shocked?
Studies suggest that technology and smartphone dependence can impact our ability to concentrate, producing symptoms similar to ADHD. Additionally, research indicates that Problematic Internet Use (PUI) may even affect brain structure and grey matter.
2) Literacy and numeracy decline
Technology also impacts how we approach literacy and mathematics. In high-income countries, 25% of adults struggle to apply mathematical reasoning when evaluating information, in the US that’s risen to 35%, according to the OECD report.
The FT article reports a sharp decrease in those who read for pleasure, something the author John Burn-Murdoch describes as ‘likely to be a result of the ongoing transition away from text and towards visual media — the shift towards a “post-literate” society.’
A 2024 study by The Reading Agency also found that only 50% of UK adults read regularly, an 8% decrease from 2015, with 30% claiming they struggle to finish what they’re reading.
3) Critical thinking and problem solving
The above issues with applying mathematical reasoning is also likely to affect the way we think critically and problem-solve. Combine that with the way we process and take in information, it’s clear we’re undermining our ability to analyse.
The OECD’s study showed this decline in maths, reading and science is visible across all age groups. The UK scored 259 out of 500 based on average proficiency in adaptive problem solving.
Is there a solution?
Although there is broad agreement that computerization and the internet are primary drivers of the downward trend in intelligence, there is little discussion of how to stop it. Although it is clear that rebuilding cognitive skills needs to happen on a mass scale, the change must begin at the personal level. Reducing screen time is the obvious place to start.
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Isabelle Knevett is a London-based investigative journalist who writes about technology and women’s issues.
