Stupid people tend to overestimate their competence, while smart people tend to sell themselves short. As Shakespeare put it in As You Like It,“The fool doth think he is wise, but the wise man knows himself to be a fool.”That conventional wisdom is backed up by a Cornell University study conducted by David Dunning and Justin Kruger. The phenomenon is now known as the Dunning-Kruger effect.

So, if you’re not too sure about your own intellect, it actually might be a indication that you’re pretty intelligent — thoughtful enough to realise your limitations, at least. Here are some signs that you are considerably smarter than you think.

You took music lessons

Research suggests that music helps kids’ minds develop in a few ways: A 2011 study found that scores on a test of verbal intelligence among 4- to 6-year-olds rose after only a month of music lessons. A 2004 study led by Glenn Schellenberg found that 6-year-olds who took nine months of keyboard or voice lessons had an IQ boost compared with kids who took drama lessons or no classes at all. Meanwhile, a 2013 study, also led by Schellenberg, suggested that high-achieving kids were the ones most likely to take music lessons. In other words, in the real world, musical training may only enhance cognitive differences that already exist.

You’re the oldest

Oldest siblings are usually smarter, but it’s not because of genetics, one study found. The New York Times reports, “The new findings, from a landmark study published [in June 2007], showed that eldest children had a slight but significant edge in IQ — an average of three points over the closest sibling. And it found that the difference was not because of biological factors but the psychological interplay of parents and children.”

You’re thin

For a 2006 study, scientists gave roughly 2,200 adults intelligence tests over a five-year period and results suggested that the bigger the waistline, the lower the cognitive ability. Another study published that same year found that 11-year-olds who scored lower on verbal and nonverbal tests were more likely to be obese in their 40s. The study authors say that smarter kids might have pursued better educational opportunities, landed higher-status and higher-paying jobs, and therefore ended up in a better position to take care of their health than their less intelligent peers. Meanwhile, a more recent study found that, among preschoolers, a lower IQ was linked to a higher BMI. Those researchers also say environmental factors are at play, since the relationship between BMI and smarts was mediated by socioeconomic status.

You have a cat

A 2014 study of 600 college students found that individuals who identified as “dog people” were more outgoing than those who identified as “cat people”, according to a test that measures personality and intelligence. But guess what? Those same cat people scored higher on the part of the test that measures cognitive ability.

You were breastfed

2007 research suggests that babies who are breastfed might grow up to be smarter kids. In two studies, the researchers looked at more than 3,000 children in Britain and New Zealand. Those children who had been breastfed scored nearly seven points higher on an IQ test — but only if they had a particular version of the FADS2 gene. Figuring out the exact mechanism of this relationship between FADS2, breastfeeding, and IQ will require further study, the scientists noted in their paper on the finding.

You’re tall

A 2008 Princeton study of thousands of people found that taller individuals scored higher on IQ tests as kids and earned more money as adults. The researchers write, “As early as age 3 — before schooling has had a chance to play a role – and throughout childhood, taller children perform significantly better on cognitive tests.”

You’re left-handed

Left-handedness used to be associated with criminality, and researchers are still unclear as to whether and why there are slightly more lefties among criminal populations. More recent research associates left-handedness with “divergent thinking,” a form of creativity that allows you to come up with novel ideas from a prompt – at least among men. In her review of a 1995 paper, New Yorker reporter Maria Konnikova writes: The more marked the left-handed preference in a group of males, the better they were at tests of divergent thought. Left-handers were more adept, for instance, at combining two common objects in novel ways to form a third – for example, using a pole and a tin can to make a birdhouse.

You learned to read early

In 2012, 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 suggest that reading from an early age increases both verbal and nonverbal (e.g. reasoning) ability, as opposed to the other way around.

You worry a lot

A growing body of research suggests that anxious individuals may be smarter than others in certain ways, according to Slate’s coverage of several different studies on anxiety. In one study, 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, as psychologist Dr. Edward Selby reported in Psychology Today. Results showed that people who tended to worry and ruminate a lot scored higher on measures of verbal intelligence, while people who didn’t do much worrying or ruminating scored higher on tests of nonverbal intelligence.

You’re funny

In one study, 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’re curious

In University of London business psychology professor Tomas Chamorro-Premuzi’s post for Harvard Business Review, he discussed how the curiosity quotient 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, individuals with higher CQ are generally more tolerant of ambiguity. This nuanced, sophisticated, subtle thinking style defines the very essence of complexity. Second, CQ leads to higher levels of intellectual investment and knowledge acquisition over time, especially in formal domains of education, such as science and art (note: this is of course different from IQ’s measurement of raw intellectual horsepower).”

You’re messy

A study published in “Psychological Science”by the University of Minnesota Carlson School of Management’s Dr 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 pingpong ball. The 24 individuals working in neat rooms came up with substantially less creative responses than the individuals working in cluttered rooms. So if you are a pack rat, tell everyone you’re just fueling your sense of creativity and innovation the next time someone tells you to clean up your act.

You’re a night owl

One study published in the The Official Journal of the International Society for the Study of Individual Differences found that, when all other variables are factored out, night owls tend to beat out early birds in terms of intellect. It concluded that ethnographic evidence indicates that “nocturnal activities” were rarer in the ancestral environment. That means that more intelligent individuals are more likely to stay up late because smarter people are more likely to “espouse evolutionarily novel values.”

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 opinions piece for The New York Times, psychologists David Z. Hambrick and Elizabeth J. Meinz cited a Vanderbilt University study of highly intelligent young people. The study tracked 2,000 people who scored in the top one per cent 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 timesmore 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.

The Independent