Leisure reading, rather than chess or complex puzzles, is the most common hobby among high scorers on intelligence tests, research reported by Forbes shows.
While popular assumptions suggest that highly intelligent individuals spend their leisure time engaging in complex mental exercises to train the brain like a muscle, cognitive studies present a different picture. Voluntary reading done for pleasure, rather than for work or study, is the single activity most strongly associated with high test scores.
Most adults quietly abandon leisure reading after childhood, yet data indicates that unprompted reading provides durable cognitive advantages that structured mental games cannot replicate.
Limits of cognitive training games
Psychological research into cognitive training consistently encounters what researchers refer to as the far transfer problem. When an individual practices a specific memory exercise or puzzle, they become highly skilled at that exact task and slightly better at closely related activities.
However, those improvements fail to generalize to broader cognitive abilities. The mental gains achieved through targeted brain exercises remain confined strictly to the specific tasks performed.
Brain training programs and puzzle games have grown into a commercial industry based on the premise that targeted mental workouts build general intelligence. Psychological consensus maintains that task specific practice rarely translates into broader real world problem solving skills.
Fluid and crystallised intelligence
To understand how reading affects the mind, psychologists separate cognitive ability into fluid intelligence and crystallised intelligence. Fluid intelligence represents the capacity to reason and solve novel problems when working with unfamiliar material.
Fluid ability remains relatively stable throughout adulthood and typically reaches its peak during youth. In contrast, crystallised intelligence encompasses the sum of a person's acquired knowledge, vocabulary, and practical understanding, which can continue expanding over several decades.
British-American psychologist Raymond Cattell described this relationship as an investment model. Under Cattell's framework, an individual spends their fluid reasoning ability on specific domains over a lifetime, solidifying those experiences into lasting crystallised knowledge.
Reading serves as an exceptionally efficient venue for this intellectual investment. Books deliver vocabulary, complex syntax, and structured ideas at a density that spoken conversation rarely achieves.
Cattell first introduced the distinction between fluid and crystallised intelligence in 1941. His investment theory remains a foundational concept in differential psychology, explaining why general knowledge and verbal comprehension often improve as people age, even as raw processing speed declines.
Format differences in print and digital reading
The medium through which a person reads plays a significant role in cognitive outcomes. A 2025 study published in the Review of Educational Research, which analyzed data from nearly half a million readers, revealed that leisure reading on digital screens shows only a weak association with reading comprehension.
This digital effect falls well short of the moderate positive link long established between print reading habits and strong comprehension skills. Researchers noted that activities yielding meaningful cognitive results closely resemble reading physical books rather than scrolling through digital news feeds.
The Review of Educational Research is a peer-reviewed academic journal published by the American Educational Research Association. Founded in 1931, the publication synthesizes empirical studies to provide comprehensive overviews of educational methodology.
A common objection to these findings is that naturally intelligent individuals simply choose to read more, making the habit a symptom of intelligence rather than its primary cause. Researchers acknowledge that this feedback loop is real and central to understanding the habit.
A child who grasps reading easily tends to read more frequently, expanding their vocabulary and background knowledge. That expanded knowledge base makes the next book easier to comprehend, creating a self-reinforcing cycle that persists quietly into adulthood.
Fiction and theory of mind claims
Many popular claims regarding the benefits of reading do not withstand scientific scrutiny. One widely cited concept suggests that reading literary fiction sharpens an individual's mental model, often called theory of mind, which is the capacity to infer what others think and feel.
A 2024 meta-analysis published in the Journal of Experimental Psychology: General, which synthesized 70 experimental studies, confirmed that the effect exists but is remarkably small. The study found that any positive impact is strictly limited to empathy and understanding others' mental states.
Furthermore, researchers discovered that the measured effect was noticeably larger in published studies than in unpublished ones, indicating publication bias and casting doubt on exaggerated claims about fiction building social intelligence.
Reading does not function like a pharmaceutical supplement or a quick fix for the mind. A stack of novels will not elevate a person's raw fluid reasoning score. Instead, the evidence supports a slower process of vocabulary expansion and factual accumulation that eases the absorption of new concepts.
The Journal of Experimental Psychology: General is a monthly peer-reviewed journal published by the American Psychological Association. First established in 1916, it publishes primary empirical research on fundamental psychological mechanisms including perception, learning, and cognition.
Audiobooks and reading volume
Researchers also evaluated whether the difficulty or prestige of reading material dictates its cognitive value. The findings indicate that total volume and diversity of reading matter far more than adhering to any canonical reading list.
Format flexibility also extends to audiobooks. A 2022 study published in the Review of Educational Research found that overall text comprehension is generally comparable whether a person reads printed text or listens to an audio recording.
Audiobooks offer nearly equivalent comprehension for general content, though researchers noted that traditional reading retained a slight advantage when passages demanded complex analytical reasoning.
Need for cognition as a driving trait
To explain why reading consistently correlates with high cognitive scores while other leisure activities do not, psychologists point to a personality construct known as the need for cognition. This trait describes a stable individual disposition to seek out and enjoy effortful mental activity.
A 2023 study published in the Proceedings of the National Academy of Sciences, which synthesized data from more than 1,300 studies, established that traits like the need for cognition show a stronger link to the cognitive aspects of intelligence than to raw reasoning power.
The trait reflects how willingly an individual applies their mental capacity when no external obligation demands it. People who score high in the need for cognition do not read for self-improvement; they read because an unanswered question creates mild discomfort that a book resolves.
The Proceedings of the National Academy of Sciences, established in 1914, is the official flagship journal of the United States National Academy of Sciences. It is one of the most cited multidisciplinary scientific journals in the world, publishing peer-reviewed research across physical, social, and biological sciences.
The findings were reported by business magazine Forbes and summarized by Ukrainian news agency UNIAN. Forbes, founded in New York in 1917, covers international business, technology, science, and economic trends.
The research reframes how lifelong intelligence develops over time. Intellectual growth is not achieved by forcing the brain through intense, artificial exercises on command, but by maintaining a steady appetite for new information. The most effective intellectual habit is also one of the gentlest, offering a quiet reminder of why so many adults overlook it.
