• Potential signs of high intelligence include being messy and worrying a lot.
• As it turns out, smart people tend to sell themselves short.
• Check out the list below and see if any of these signs apply to you.

As Shakespeare put it in his romantic comedy "As You Like It": "The fool doth think he is wise, but the wise man knows himself to be a fool."

In other words, smart people often underestimate their brain power. 

That idea is backed up by a Cornell University study conducted by social psychologists David Dunning and Justin Kruger. The phenomenon — now known as the Dunning-Kruger effect — is the tendency for those with low abilities in certain areas to overestimate their own competence, and those with higher abilities to assume the task is simple for everyone. 

If you're not too sure about your own intellect, it could indicate that you're pretty intelligent — thoughtful enough to realize your limitations, at least.

Here are some subtle signs that you are considerably smarter than you think.

Drake Baer and Chelsea Harvey contributed to a previous version of this article.

You learned to read early

For a 2014 study, researchers looked at nearly 2,000 pairs of identical twins in the UK and found that the sibling who had learned to read earlier tended to score higher on tests of cognitive ability.

The study authors suggested that reading from an early age would increase both verbal and nonverbal (i.e. reasoning) ability, as opposed to the other way around.

However, a 2017 paper argued that the 2014 report didn't fully account for environmental and genetic factors that may have been driving the differences in intelligence.

You worry a lot

Anxious individuals may have a leg up in certain forms of intelligence than their carefree counterparts. 

In 2015, Slate compiled a series of studies that explored the link between worrying and intelligence. 

In one 2015 study published in the journal Personality and Individual Differences, for example, researchers asked 126 undergrads to fill out questionnaires in which they indicated how often they experienced worry. They also indicated how often they engaged in rumination, or thinking continuously about the aspects of situations that upset them.

Results showed that people who tended to worry and ruminate a lot scored higher on measures of verbal intelligence, while people who didn't worry or ruminate much scored higher on tests of nonverbal intelligence. 

More recently, a 2018 study published in the journal, Intelligence, found that members of Mensa were more likely to be diagnosed with mood disorders, ADHD, or autism compared to national averages. 

You're curious

Tomas Chamorro-Premuzic, business psychology professor at University of London, wrote an article for Harvard Business Review in which he discussed how the curiosity quotient, CQ, and having a hungry mind makes one more inquisitive.

Regarding the importance of CQ, he wrote that, "It has not been as deeply studied as EQ and IQ, but there's some evidence to suggest it is just as important when it comes to managing complexity in two major ways."

First, smarter people are generally more tolerant of ambiguity. Second, CQ leads to higher levels of "intellectual investment" and learning more over time.

A Goldsmiths University of London study found that intellectual investment, or "how people invest their time and effort in their intellect," plays a major part in cognitive growth.

You're messy

A study published in Psychological Science by the University of Minnesota Carlson School of Management's Kathleen Vohs revealed that working in an untidy room actually fuels creativity.

In the study, 48 participants were asked to come up with unusual uses for a ping-pong ball. The 24 individuals working in neat rooms came up with substantially less creative responses than the individuals working in cluttered rooms.

And a 2015 study from the University of Groningen in the Netherlands found that disordered environments prompt people to be more goal-oriented. The findings suggest that we're hardwired to seek order in our lives whenever possible. So when we're faced with physical chaos, we're motivated to create a more abstract sense of organization by pursuing clear, well-defined goals.

You didn't have sex until after high school

High schoolers with higher IQs are more likely to be virgins than those with average or lower IQs, according to a study from the University of North Carolina Chapel Hill. The core sample looked at 12,000 teens from the 7th to the 12th grade.

Not only were the teens with the higher IQs more likely to be virgins, they were also less likely to kiss or hold hands with a romantic partner.

Meanwhile, a 2012 study published in the journal Developmental Psychology found that adolescents with higher working memory ability were less likely to have sex.

You're a night owl

The evolutionary scientist Satoshi Kanazawa found that when you sleep might have something to do with your abilities. 

In a 2009 study published in the journal Personality and Individual Differences, Kanazawa looked at the link between childhood IQ and sleep habits among thousands of adolescents. Results showed that higher-IQ teens said they stayed up later and woke up later on both weekdays and weekends.

In an earlier study from 2006, researchers from Catholic University in Milan found that late sleepers may be more likely to develop original and creative solutions to problems than morning people, according to ABC Science's coverage of the study. 

You don't always have to try hard

This isn't to say that laziness is a sign of being smart. But it is fair to say that smart people simply don't always have to try as hard as "strivers" who fight to build up their skills — at least in certain fields. In an opinion piece for The New York Times, psychologists David Hambrick and Elizabeth Meinz cited a Vanderbilt University study of highly intelligent young people.

The study tracked 2,000 people who scored in the top 1% of the SAT by the age of 13. Hambrick and Meinz wrote that, "The remarkable finding of their study is that, compared with the participants who were 'only' in the 99.1 percentile for intellectual ability at age 12, those who were in the 99.9 percentile — the profoundly gifted — were between three and five times more likely to go on to earn a doctorate, secure a patent, publish an article in a scientific journal or publish a literary work. A high level of intellectual ability gives you an enormous real-world advantage."

They concluded that while striving to be smarter is commendable, there are certain innate abilities that can't always be learned.

That said, Florida State University psychologist Anders Ericsson has found that "deliberate practice," which involves constantly pushing yourself beyond your comfort zone, is the only way to master a particular skill — regardless of your intelligence level.

You took music lessons

A growing body of evidence suggests that music helps kids' minds develop. 

In a 2018 study published in the journal Frontiers in Neuroscience, kids who were given structured music lessons performed better than their peers on tests of verbal intelligence, planning, and inhibition.

According to a small 2011 study published in the journal Psychological Science, the verbal intelligence of 4- to 6-year-olds rose after less than a month of music lessons.

Another study published in the journal Psychological Science in 2004 found that 6-year-olds who took nine months of piano lessons had an IQ boost compared with kids who took drama lessons or no classes at all.

You're the oldest

Older and wiser might actually be true among siblings. 

According to research published in the Journal of Human Resources cited by CNBC, first-born children are more likely to perform better on cognitive tests than their younger siblings. A 2017 paper from the National Bureau of Economic Research also found that older children are 30% more likely to become CEOs or politicians. 

You've used recreational drugs

A 2012 study of more than 6,000 Brits born in 1958 found a link between high IQ in childhood and the use of illegal drugs in adulthood.

"In contrast to most studies on the association between childhood IQ and later health," their findings suggest "a high childhood IQ may prompt the adoption of behaviors that are potentially harmful to health (i.e., excess alcohol consumption and drug use) in adulthood."

You're left-handed

While left-handedness used to be associated with criminality, more recent research associates it with "divergent thinking," a form of creativity in which you come up with novel ideas from a prompt.

A 1995 paper found that left-handed males had higher scores on divergent thinking. As Maria Konnikova writes for The New Yorker, that means they were better at tasks like combining two common objects in creative ways to form a third and grouping lists of words into as many alternate categories as possible.

Maybe that's why lefties are overrepresented in architecture and music.

You're funny

In one 2011 study published in the journal Intelligence, 400 psychology students took intelligence tests that measured abstract reasoning abilities and verbal intelligence.

Then they were asked to come up with captions for several New Yorker cartoons, and those captions were reviewed by independent raters.

As predicted, smarter students were rated as funnier.

You drink alcohol regularly

Satoshi Kanazawa and colleagues also found that British and American adults who scored higher on IQ tests when they were kids drank more alcohol more often in adulthood than those who had scored lower.

Some other studies support that finding as well, including a 2013 paper published in the journal Intelligence that found nations with a higher average IQ score also tend to drink more beer and wine. Interestingly, a 2013 study of young Swiss men found that moderate alcohol consumption was most strongly linked to high IQ.

A 2021 study published in Scandinavian Journal of Public Health that analyzed the behavior of Norwegian men in their 20s, found there was a positive correlation between drinking and intelligence for those in their late 20s, but no specific correlation for those in their early 20s.  

ncG1vNJzZmivp6x7o8HSoqWeq6Oeu7S1w56pZ5ufonxyf4ysoKCmo2LBqa3TZrCoraKaerS5wKurnqpdqbWiuoyypq5lpJ22r7eMsqauZZGnsm5%2Bj2tqZmk%3D