The post What Research Says About 7 Habits Linked to Intelligence, and Which Are Myths first appeared on Crafting Your Home.
We often assume intelligence is easy to recognize. Someone who asks thoughtful questions, reads constantly, enjoys difficult problems, or stays awake late into the night may appear exceptionally intelligent.
But psychology research tells a more complicated story. Everyday habits can be associated with cognitive ability, learning, knowledge, or short-term mental performance without actually being reliable signs of a person’s IQ.
Intelligence broadly involves learning, adapting, understanding, reasoning, and using information. IQ, by contrast, is a standardized score based on performance compared with people of the same age. No bedtime, hobby, personality trait, or everyday behavior can reliably reveal someone’s IQ simply by observation.
Intellectual Curiosity
Curiosity is one of the more interesting behaviors associated with cognitive ability. People who enjoy discovering information, exploring unfamiliar subjects, and understanding how things work may show some overlap with measured cognitive ability.
A five-year German study found a correlation between intellectual curiosity and cognitive ability, with an initial correlation of r = 0.27.
The research also examined academic performance, although the findings did not establish that curiosity causes higher ability or better grades. The study experienced considerable participant attrition and included self-reported academic information, which limits how strongly the findings can be interpreted.
Curiosity, therefore, can accompany cognitive ability without functioning as a simple test of intelligence.
Related: 9 Everyday Habits Psychologists Associate With High Emotional Intelligence
Reading and Developing Reading Skills
Reading is frequently described as a habit that makes people smarter, but the research is more nuanced than that popular claim suggests.
A UK study involving 1,890 identical-twin pairs found that earlier differences in reading ability were associated with later differences in some intelligence-test scores. However, a later reanalysis of the same data substantially weakened the argument that reading ability itself caused intelligence to increase after accounting for stable influences.
This distinction matters. Reading ability, reading frequency, reading for pleasure, and general intelligence are not interchangeable. Reading can certainly develop knowledge and language skills, but the evidence does not support promising that regularly reading books automatically raises IQ.
Enjoying Difficult Mental Challenges
Some people genuinely enjoy difficult questions, complicated ideas, puzzles, and activities that require sustained concentration. Psychologists often study this tendency through concepts such as need for cognition and typical intellectual engagement.
A 2025 preregistered meta-analysis found modest associations between intellectual engagement and several measures of intelligence.
The relationship was stronger with crystallized intelligence, which involves acquired knowledge and skills, than with fluid intelligence, which involves reasoning through relatively new problems.
The important point is that these findings describe an association between a psychological disposition and measured ability. They do not prove that taking up challenging hobbies will automatically increase someone’s IQ.
Regular Exercise
Exercise is another behavior often promoted as a way to improve brainpower. Research does provide evidence that physical activity can affect certain measures of cognitive performance, but the size and reliability of those effects remain debated.
A large 2025 umbrella review covering 133 reviews, 2,724 randomized trials, and 258,279 participants reported improvements in general cognition, memory, and executive function.
However, a separate 2023 review focused on healthy populations found that its initially estimated cognitive benefit became negligible after accounting for publication bias.
These differences show why the simple statement “exercise makes you smarter” goes too far. Exercise research can examine changes in measured cognitive performance, but that is not the same as proving a permanent increase in IQ.
Getting Enough Sleep
Sleep can strongly affect how well the brain performs, but sleeping well should not be confused with having higher intelligence.
A 2024 meta-analysis examined 44 studies involving one night of restricted sleep. Researchers found that sleep restriction significantly impaired sustained attention, while several other areas, including working memory and inhibitory control, did not show significant pooled effects.
This suggests that sleep can influence how effectively someone performs mentally at a particular time. It does not show that people with a particular bedtime or sleep routine necessarily have higher intelligence.
Being Comfortable Saying “I Don’t Know”
Intellectual humility, the willingness to recognize the limits of one’s knowledge, may be valuable even though it is not an IQ indicator.
Research involving five studies and 1,189 participants found that intellectual humility was associated with greater general knowledge and less tendency to claim knowledge that participants did not possess. However, it was not associated with measured cognitive ability in the reported findings.
Knowing when you do not know something can therefore be an intellectually useful habit without proving that someone has a higher IQ.
Staying Up Late
The idea that night owls are smarter is one of the most popular intelligence myths, but research does not support it as a universal rule.
An updated meta-analysis examined 30 studies involving 11,160 participants and found no significant overall relationship between morningness and intelligence. The reported overall correlation was almost zero, although some age-specific patterns differed.
This is an important reminder that chronotype, bedtime, sleep duration, and intelligence are different things. Staying awake late does not provide a reliable indication of someone’s IQ.
Related: 8 Common Phrases Used by People With Extremely Low Intelligence
What About Messy Rooms, Swearing, Self-Talk, and Solitude?
Several other popular “signs of intelligence” are based on research that measured something different from intelligence. Studies involving messy rooms examined creativity rather than IQ.
Research on private speech found a task-level relationship with working-memory performance, not evidence that people who talk to themselves have higher IQs. Studies involving swearing have distinguished between generating taboo words during a verbal task and actually swearing frequently in daily life.
These examples demonstrate why viral intelligence claims should be treated carefully. A finding involving creativity, memory, vocabulary, knowledge, or life satisfaction cannot automatically be converted into a claim about IQ.
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