How do you know if someone's smart?

Without administering an impromptu IQ test, there are certain clues you can use to gauge a person's relative intelligence.

We combed through decades of scientific research and highlighted 13 surprising signs of braininess.

Keep in mind, however, that "intelligence" is often measured through tests that have been [You must be registered and logged in to see this link.] for putting certain social groups at a disadvantage and for minimizing the importance of creativity. Psychologists are constantly finding newer, more effective ways to measure cognitive ability — meaning the signs are ever evolving.

Additional reporting by Chelsea Harvey.

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