Do night owls, messy people and frequent swearers really tend to be smarter? The honest answer is: a little, sometimes, and not in the way viral headlines suggest. A handful of real studies found small links between intelligence and staying up late, between verbal fluency and knowing lots of swear words, and between messy surroundings and more original ideas. None of them show that these habits make you intelligent, or that tidy early risers are less clever. Here is what each study actually measured, what it found, and how to read it.
The short version
- Night owls: analyses of large samples find a small positive association between an evening chronotype and intelligence. Correlation, not cause.
- Swearing: a 2015 study found that people who could list more taboo words in a minute also listed more ordinary words. It measured fluency, not how often people swear.
- Messiness: a 2013 experiment found that sitting in a messy room nudged people toward more creative ideas, while a tidy room nudged them toward healthier and more generous choices.
So the fair takeaway is not "bad habits mean genius," but "these habits are not the signs of a dull mind that people often assume."
Night owls and intelligence
The idea took off with a 2010 Psychology Today post by Satoshi Kanazawa, an evolutionary psychologist at the London School of Economics. Using data from a large representative sample of young Americans, he reported that people who scored higher on intelligence tests as children went to bed later as young adults, on weeknights and weekends alike, and woke later on weekdays. The gap was modest: on weeknights, the most intelligent group went to bed around 48 minutes later than the least intelligent group.
Kanazawa's explanation was evolutionary. He argued that staying active long after dark was rare for most of human history, and that more intelligent people may be more drawn to "evolutionarily novel" behaviour. That part is a theory, not something the data directly tested.
Later work has been more cautious but broadly consistent. A meta-analysis found a small positive association between evening chronotype and intelligence, and a large UK Biobank analysis reported something similar.
What a chronotype is
Your chronotype is your natural tendency to sleep and wake at particular times, set by your internal circadian clock. Most people sit somewhere between strong "larks" and strong "owls." It is partly genetic, with dozens of gene variants linked to it, and it shifts with age: children tend to be early, teenagers drift later, and many older adults become early risers again.
Being an owl also has costs. Evening chronotypes have been associated with higher risk of depression and with some metabolic problems, often because owls live on a schedule built for larks and end up short of sleep. The healthiest choice is less about the hour you sleep and more about getting enough regular sleep. If tiredness affects your daily life, talk to a doctor.
Swearing and vocabulary
A popular belief holds that people swear because they cannot think of anything better to say, sometimes called the "poverty of vocabulary" view. In 2015, psychologists Kristin Jay and Timothy Jay tested it in the journal Language Sciences.
Student volunteers did three one-minute tasks: name as many swear words as possible, name as many animals as possible, and name as many general words starting with a given letter. On average they produced about 9 taboo words, 14 letter-based words and 22 animals. The key finding was that scores moved together: people who were good at one task tended to be good at the others. The authors summed it up as "fluency is fluency."
That does not mean swearing a lot signals intelligence. The study measured how many taboo words people knew, not how often they used them, and it did not test IQ. What it does undercut is the lazy assumption that swearing shows a limited vocabulary.
The comedian and writer Stephen Fry has made a similar point in a widely shared clip, arguing that treating swearing as proof of poor education is itself unthinking. Whatever your view, context still matters: language that works among friends can cost you at a job interview.
Messy desks and creativity
The third claim comes from Kathleen Vohs and colleagues at the University of Minnesota, published in Psychological Science in 2013. Their experiments placed volunteers in either a tidy or a cluttered room and gave them small tasks.
- People in the tidy room were more likely to choose an apple over chocolate and gave more money to charity.
- When asked to invent new uses for ping-pong balls, both groups came up with the same number of ideas, but independent judges rated the ideas from the messy room as more interesting and creative.
- Offered a choice between a new product and an established one, people in the messy room more often chose the new one.
Vohs summarised it like this: "Disorderly environments seem to inspire breaking free of tradition, which can produce fresh insights." Note what the study did not show. It looked at the effect of a room on people's choices in the moment, not at whether naturally messy people are more intelligent. Order and disorder each brought different benefits.
Myths and misquotes to drop
Articles on this topic often close with Albert Einstein supposedly asking what an empty desk says about a person, if a cluttered desk signals a cluttered mind. Quote researchers have found no evidence Einstein said it. The attribution first appears around 2006, half a century after his death, while a close version ran in a 1955 newspaper with no link to him.
Another myth is the jump from correlation to identity. A small average difference between groups says almost nothing about any individual. Plenty of brilliant people are tidy, polite morning people, and plenty of messy night owls are not geniuses.
Finally, the original Psychology Today framing, "more intelligent than," overstates findings that were small and observational.
What to take from the research
If you stay up late, curse when you stub your toe or work best surrounded by piles of paper, you do not need to feel guilty about it on intelligence grounds. These habits are not markers of a weak mind.
The more useful lessons are practical. Protect your sleep whatever your chronotype. Use colourful language with an eye on your audience. And use your surroundings deliberately: a bit of creative clutter can help when you are brainstorming, while a clean, ordered space may help when you need discipline, such as sticking to a budget or a healthy routine.
Sources: Satoshi Kanazawa, Psychology Today (2010); Wikipedia: Chronotype; BPS Research Digest on Jay & Jay (2015), Language Sciences; Association for Psychological Science on Vohs et al. (2013); Quote Investigator; original article by Raven Fon via I Heart Intelligence.
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