Before we talk about traits that intelligent people share, we have to come up with a working definition of intelligence itself. Some describe it as the ability to take in knowledge and then put it to work for you. There is definitely an element of learning — which means your ability to understand new information and respond to it in creative, self-aware ways.

Many researchers have studied what intelligence means and devised some identifying traits that mark some as intelligent and others as lacking in that area. The traits in this list come from their research. Just because you lack one (or some, or even many) of these characteristics does not mean that you lack intelligence, but it is interesting to see what most intelligent people have in common.

1. They Are Skinny


Given the fact that so many people struggle with obesity, this might be a controversial item on the list. However, studies have found that people who have a higher BMI (Body Mass Index) show lower performance levels on cognitive ability testing. Of course, that would also mean that some fairly hefty people (think Orson Welles and Vincent D’Onofrio, for example) lack intelligence — which isn’t true. But it is smart to stay as healthy as possible.

2. They Experiment With Drugs


A 2012 study looked at the IQ test results of children and patterns of using illegal drugs. High school students who ranked higher on the IQ scale were actually more likely to use illegal drugs than their counterparts with lower IQs. Obviously, this doesn’t mean that using drugs makes you smart — research shows that illegal drug use and alcohol abuse bring you IQ down. However, those who showed higher IQ results were more likely to try drugs.

4. Their Mothers Breastfed Them

Group Of Mothers With Babies At Playgroup

Breastfeeding brings a number of benefits to a baby — both physically and emotionally — and studies now indicate that breastfeeding can boost a child’s intelligence. So the next time you’re tempted to make fun of a woman who is breastfeeding her child in public, remember that she’s doing that baby a favor.

4. They Are Left-Handed


While most people are right-handed, a look back at history shows that many of the most intelligent and influential people in world history have used their left hand. American President Barack Obama is left-handed, as was President George H.W. Bush. Leonardo da Vinci, author James Baldwin, and Alexander the Great all used their left hands.

5. They Get Into Disagreements With Other People


Many disagreements happen because people fail to understand one another. If you’re intelligent, you look at things from a perspective that differs from many other people, and so you can end up in conflict. An intelligent person is more likely to ask the question “Why,” which can frustrate others who are less intelligent.

6. They Ask a Lot of Questions


Remember that kid in your fourth-grade class who wouldn’t stop asking questions? A lot of children like that enter adulthood and still have an incredible spectrum of curiosity, a trend that might amuse some of us who have stopped looking into everything and now just give life a modicum of attention.

7. They’re Happy Spending Time By Themselves


This doesn’t mean that all intelligent people are introverts (or vice versa), but those who are intelligent find productive things to do when they are alone. If you’re intelligent, you want to find ways to improve yourself every day. This is why so many people of average intelligence sit in front of their television, while those at the highest intelligence levels are finding the next innovations.

8. They Calculate Risk Before Diving In


You might think that intelligent people would avoid risk altogether. However, that’s not the case — after all, when you take a risk, you open yourself up for an even better reward. However, intelligent people take a hard look at the risks involved. Even when they hit rock bottom, intelligent people will oftentimes rise up out of those ashes and succeed mightily.

9. They Show High Levels of Self-Control


I know what you’re thinking — yes, we did say that intelligent people are more likely to use illegal drugs. However, there are people who can integrate the use of such substances as marijuana into a productive life. High intelligence includes the ability to put knowledge to use. When is it the right idea to use those drugs? What is the best choice at the dinner table? (Remember, highly intelligent people are also more likely to be thin).

10. They Keep An Open Mind

Guy with open mind

If you are highly intelligent, you’re more likely to have a willingness to try new things and listen to novel ideas, no matter what ideas and beliefs you learned growing up. If you are willing to learn, you keep an open mind — and that willingness to learn is a key part of high intelligence.