Study reveals decline in human cognitive abilities
A large-scale scientific study conducted on nearly 400,000 people in the United States has revealed a notable decline in certain mental and cognitive abilities in recent years. These findings reinforce what is scientifically known as the “reverse Flynn effect,” a trend indicating that modern generations have performed worse on intelligence tests after decades of continuous improvement.
The study was published in the journal *Intelligence* and conducted by researchers from Northwestern University in the United States. They emphasized that this decline does not necessarily mean humans have become “less intelligent,” but rather points to complex changes in thinking patterns and cognitive abilities.
Over a century ago, French scientists developed the Binet intelligence test, which was later introduced to the United States, where it was widely used in schools and various institutions.
Since the 1930s, scientists have observed that average intelligence scores rose by about 3 points per decade. This phenomenon became known as the “Flynn effect,” named after researcher James Flynn, who described it in 1984.
Scientists attributed this rise to multiple factors, including improved nutrition, educational advancements, smaller family sizes, and the increasing complexity of the environments in which humans live.
To verify whether this trend had reversed in the United States, researcher Elizabeth Dvorak and her colleagues analyzed data from 394,378 adults aged 18 to 90.
The results showed a decline in overall cognitive scores during the study period, regardless of age, gender, or educational level. The most significant decline was recorded among young people aged 18 to 22, as well as among those with lower educational attainment.
Performance also dropped in tests involving pattern recognition, abstract reasoning, problem-solving, and logical thinking based on sequences of letters and numbers.
Researcher Elizabeth Dvorak said she initially thought there was an error in the data analysis. She added, “I reviewed the code for weeks and thought I had made a mistake, but after reviewing it with the study supervisor, we confirmed that the results were correct.”
Not all mental abilities declined; participants showed improvement in three-dimensional spatial visualization tests. Researchers suggest that the widespread use of video games may have contributed to enhancing this skill.
The study does not provide a direct explanation for the causes of this decline, but it indicates that the phenomenon began before the rise of generative artificial intelligence and before the coronavirus pandemic, ruling out either as the primary cause.
Conversely, the onset of the decline coincided with the widespread adoption of smartphones in the late 2000s. This has led some researchers and commentators to question whether rapid screen reading and social media content have affected thinking styles and concentration.
British writer James Marriott argues that the shift from reading printed books to consuming short content on mobile phones has weakened logical thinking and deep analysis, because extended reading requires building interconnected ideas and comprehending more complex information.
Researchers stress that the study’s results do not mean humans have become stupider in the traditional sense, but rather that mental abilities are changing over time. Some skills may decline while others improve, reflecting the impact of technological and cultural changes on human thought.
