Several Quora users noted that intelligent people are flexible and able to thrive in different settings. As Donna F Hammett writes, intelligent people adapt by "showing what can be done regardless of the complications or restrictions placed upon them."
Recent psychological research supports this idea: Intelligence depends on being able to change your own behaviors in order to cope more effectively with your environment or make changes to the environment you're in.
They understand how much they don't know
The smartest folks are able to admit when they aren't familiar with a particular concept. As Jim Winer writes, intelligent people "are not afraid to say: 'I don't know.' If they don't know it, they can learn it."
Winer's observation is backed up by a classic study by Justin Kruger and David Dunning, which found that the less intelligent you are, the more you overestimate your cognitive abilities.
In one experiment, for example, students who'd scored in the lowest quartile on a test adapted from the LSAT overestimated the number of questions they'd gotten right by nearly 50%. Meanwhile, those who'd scored in the top quartile slightly underestimated how many questions they'd gotten right.
They have insatiable curiosity
Albert Einstein reportedly said, "I have no special talents, I am only passionately curious."
Research published in 2016 suggests that there's a link between childhood intelligence and openness to experience (which encompasses intellectual curiosity) in adulthood. Scientists followed thousands of people born in Great Britain for 50 years and learned that 11-year-olds who'd scored higher on an IQ test turned out to be more open to experience at age 50.
Smart people don't close themselves off to new ideas or opportunities. Hammett writes that intelligent people are "willing to accept and consider other views with value and broad-mindedness" and that they are "open to alternative solutions."
Psychologists say open-minded people — those who seek out alternate viewpoints and weigh the evidence fairly — tend to score higher on the SAT and on intelligence tests.
At the same time, smart people are careful about which ideas and perspectives they adopt. "An intelligent mind has a strong aversion to accepting things on face value and therefore withholds belief until presented with ample evidence," says Alas.
Interestingly, recent research suggests that smarter people tend to derive less satisfaction than most people do from socializing with friends.
They have high self-control
Zoher Ali writes that smart people are able to overcome impulsiveness by "planning, clarifying goals, exploring alternative strategies and considering consequences before [they] begin."
Scientists have found a link between self-control and intelligence. In one 2009 study, participants had to choose between two financial rewards: a smaller payout immediately or a larger payout at a later date. Results showed that participants who chose the larger payout at a later date (i.e. those who had more self-control) generally scored higher on intelligence tests.
The researchers behind that study say that one area of the brain — the anterior prefrontal cortex — might play a role in both helping people solve tough problems and demonstrate self-control while working toward goals.
Scientists agree. One study found that people who wrote funnier cartoon captions scored higher on measures of verbal intelligence; another study found that professional comedians scored higher than average on measures of verbal intelligence.
They're sensitive to other people's experiences
Smart people can "almost feel what someone is thinking/feeling," says He.
Some psychologists argue that empathy, being attuned to the needs and feelings of others and acting in a way that is sensitive to those needs, is a core component of emotional intelligence. Emotionally intelligent individuals are typically very interested in talking to new people and learning more about them.