If you want to better understand someone's personality, there's no shortage of options. Psychologists have developed various checklists and inventories to evaluate everything from whether someone is a card-carrying psychopath to a drama queen.

If you're looking for a more holistic, research-backed approach, there are various tests of the so-called Big Five personality traits. Or you could always go with Myers Briggs, though be warned that despite its popularity in the business world, there's no evidence it beats astrology at characterizing people.

All of these choices might be an insightful way to investigate your own character, but if you're trying to get a handle on another person, they're probably a little cumbersome. That new job candidate (or date) would probably look at you a little funny if you sent over an online narcissistic personality test. Is there a quick and dirty--but scientifically validated--way to assess if a given individual has a certain personality trait?

Yup, according to a study out of Wake Forest University recently highlighted on PsyBlog. If you want to know if someone displays a certain characteristic, just ask if he or she thinks other people often do.

Can one type of question reveal all?

To reach this conclusion, a team led by psychologist Dustin Wood asked study subjects (in this case that typical psychological guinea pig, the undergrad) to rate the personalities of several acquaintances. Their responses said much more about themselves than they probably intended.

The more frequently people rated others as kindhearted, happy, emotionally stable, or courteous, the more likely they were to rate themselves as having these traits, and the more likely outside evaluators were to agree. And the results remained stable even when the subjects were tested again a year later. "Seeing others positively reveals our own positive traits," Wood commented.

The same thing worked for darker personality traits, too. Those with a Machiavellian streak, for instance, are more likely to see others as manipulative. "A huge suite of negative personality traits are associated with viewing others negatively," Woods added. "The simple tendency to see people negatively indicates a greater likelihood of depression and various personality disorders."

Besides being a fascinating glimpse into the weird and complex human mind, the findings also suggests a powerful hack for evaluating others people's character--if you want to know if they themselves display a trait, just find a way to ask how common they think it is in others. The more of a quality they see around them, the more they probably possess themselves.