Most of us love to take a good self-knowledge quiz—even something as silly as “Which ‘Friends’ character are you?” (I’m “Phoebe,” by the way.)

I’m sure that this love of quizzes is one reason that so many people have taken my “Four Tendencies” quiz. This quiz tell you whether you’re an Upholder, Questioner, Obliger, or Rebel. More than 3.5 million people have taken this quiz.

My Four Tendencies quiz, however, is quite serious. It took me more than a year to craft the language to distinguish accurately among the four types of personalities.

It’s very useful to know your Tendency, because that knowledge lets you make habits more effectively, experience less frustration with yourself and other people, and work and live more harmoniously at work and in life.

Of course, you can take the quiz yourself, and if you’re curious about other people’s Tendencies you can suggest that they take it.

But I’ve noticed that, even without the quiz, people can usually predict the Tendencies of important people in their lives. For instance, writer Zibby Owens told me that she thought that each of her four children was a different Tendency. Later, she asked them to take the quiz, and sure enough, she was right.

When I talk about the Four Tendencies at conferences, I notice that as I describe each Tendency, people will often start laughing and pointing to someone in the audience; they recognize a co-worker’s Tendency immediately.

So if you know the Four Tendencies, test your knowledge! Choose some family members, friends, or co-workers, and try to identify their Tendency. Then ask them to take the quiz, and see how well you scored.

The quiz is free and quick to take.

If you can’t persuade someone to take the quiz, you can consult my “Flash Evaluation.” (Click here and you’ll find it under “The Four Tendencies.”)

You can also try to identify the Tendencies of the Game of Thrones characters.

Let me know how you do! I’d be very curious to hear. I’m guessing that certain Tendencies—Rebels and Upholders—are particularly easy to spot.

Now you may be asking—and if you’re a Questioner, you’re certainly asking—”Why should I bother to try to figure out someone else’s Tendency?”

Because knowing someone’s Tendency makes it much easier to communicate effectively.

• Talking to a Questioner? Be sure to explain why you’re asking—why should this person do this task, in this way, by this date?
• To a Rebel? Include language such as, “If it works for you,” “If this sounds like fun,” “If this is something that interests you,” “If you feel like it, please feel free to join us…”
• To an Obliger? Show that you’re paying attention to whether that thing gets done, and that it matters to you.
• To an Upholder? Be clear about what you’re asking for, and by when.

The Four Tendencies can also reduce conflict. I’ve talked to so many couples, parents, doctors and nurses, teachers, and coaches who have used the framework. When we ask or tell someone to do something, if we frame it in the way that makes sense to them, they’re far more likely to cooperate.

It’s remarkable to me how a simple change in language can make it so much easier for people to live and work together in harmony.

If you’d like to learn more about the Four Tendencies, how to apply them in different situations, and watch fascinating interviews with each Tendency, click here.