Usually, when we picture a narcissist, we picture someone vain, confident, and completely uninterested in anyone else but himself. (I'll let you choose your own favorite celebrity example.) But according to science, there's actually a whole other, quieter harder-to-spot type of narcissist out there -- the covert narcissist.

All narcissist are self-obsessed, but it turns out not all are confident of their own greatness. While your garden-variety egomaniac will preen and brag and generally make herself the center of attention, a covert narcissist will be just as self-focused, but in a defensive way. Covert narcissists are convinced on their specialness, but they're not convinced the world gives them their due, so they're constantly on the lookout for slights, insults, and underestimations of their specialness.

In other words, covert narcissists trade swagger for sensitivity, social discomfort, and sob stories. And that can be the perfect honey trap for kinder and more empathetic souls, therapist Elinor Greenberg warns on Business Insider. "They make themselves look like the victim," she says. "There tends to be a string of misfortune, like every single ex is a jerk, every single friend they have is unhealthy."

A diagnostic checklist for undercover narcissists

If all this is touchy, quiet hyper-vigilance is starting to sound a little familiar to you, how can you be sure that problem friend, love interest, or colleague is actually a covert narcissist masquerading as a sensitive introvert? A useful 2013 Scientific American article from author Scott Barry Kaufman offers a handy, scientifically validated checklist.

The list of 23 signs of covert narcissism is written in the first person and intended for self-diagnosis, but it could just as easily be used to assess the suspect secret narcissist in your life. Just rate how well the person resembles each statement on a scale of one to five, with one being you strongly disagree and the person doesn't resemble the statement at all, and five being something you strongly agree with and find very characteristic of the person.

  1. I can become entirely absorbed in thinking about my personal affairs, my health, my cares or my relations to others.

  2. My feelings are easily hurt by ridicule or the slighting remarks of others.

  3. When I enter a room I often become self-conscious and feel that the eyes of others are upon me.

  4. I dislike sharing the credit of an achievement with others.

  5. I feel that I have enough on my hand without worrying about other people's troubles.

  6. I feel that I am temperamentally different from most people.

  7. I often interpret the remarks of others in a personal way.

  8. I easily become wrapped up in my own interests and forget the existence of others.

  9. I dislike being with a group unless I know that I am appreciated by at least one of those present.

  10. I am secretly "put out" or annoyed when other people come to me with their troubles, asking me for their time and sympathy.

  11. I am jealous of good-looking people.

  12. I tend to feel humiliated when criticized.

  13. I wonder why other people aren't more appreciative of my good qualities.

  14. I tend to see other people as being either great or terrible.

  15. I sometimes have fantasies about being violent without knowing why.

  16. I am especially sensitive to success and failure.

  17. I have problems that nobody else seems to understand.

  18. I try to avoid rejection at all costs.

  19. My secret thoughts, feelings, and actions would horrify some of my friends.

  20. I tend to become involved in relationships in which I alternately adore and despise the other person.

  21. Even when I am in a group of friends, I often feel very alone and uneasy.

  22. I resent others who have what I lack.

  23. Defeat or disappointment usually shame or anger me, but I try not to show it.

How did your suspected secret narcissist score? "The average score on this scale was in the mid-upper 60s," reports Kaufman so if you, your colleague, or your significant other scores somewhere around there, not to worry. We're all a little bit narcissistic sometimes.

But "if your score was above 97, well, you might want to own yourself as a card-carrying covert narcissist, instead of constantly telling people to stop criticizing you because your sensitive, introverted soul can't handle it," Kaufman proclaims.