How do you get people to speak more candidly than they might care to? In most cases, some amateur psychology does the trick, says Greg Hartley, a former U.S. Army interrogator and co-author of The Most Dangerous Business Book You'll Ever Read. Most people, Hartley says, fall into one of a number of personality types. The trick is to profile your subject quickly and deploy the right set of techniques. "It's taking their psyche and using it to your advantage," says Hartley, who over the course of his career has dislodged data from CEOs and terror suspects alike. Below, five of the most common personality types—and what it takes to make them talk.




Teachers believe that their knowledge and experience are their greatest assets. Consultants, academics, analysts, and other knowledge workers tend to be teachers.

Play the naive student. Flatter their smarts; coo with interest at their stories and opinions. Downplay your knowledge, but demonstrate that you are a sharp learner by listening closely and asking lots of questions (for example, "This probably sounds obvious to you, but…"). Teachers are happiest when they feel like experts, so let them.

At conferences, they are the folks who say learnings instead of lessons and choiceful instead of choosy. Jargon dorks are often young and ambitious and hope that fancy terminology will mask their inexperience.

When they bust out a highfalutin business term, politely ask what it means: "I always hear that term, SWOT analysis. What is it, exactly?" As they explain the term's intricacies, continue to play dumb. The dorks will naturally turn to real-life anecdotes to explain the argot's usefulness and show off their command of the topic. Keep your interest ostensibly focused on the business concept while keeping them talking about their work.

You don't have to look hard to find complainers—in most cases, they will find you, and they can't wait to tell you about the long line at the post office, the interminable traffic jam this morning—or why their employers are the dumbest people ever.

If they are not bellyaching already, spark a kvetchfest with a mild complaint of your own related to the topic you want to hear about. Stoke the grumbling with your stories and lots of "Man, I hear you" empathy.

Smartypantses are like teachers with chips on their shoulders. It's not enough to be knowledgeable; they have to be smarter than everybody else, including you. Smartypantses are also naturally argumentative.

Knowingly make an incorrect statement, and smartypantses will rush to correct you. Or better yet, provoke them. "That deal? No way it'll ever happen!" Watch as they rush to prove you wrong, even if it means spilling the beans to make their point.

Worriers' worst nightmare is saying something that could get them in trouble or put them in the spotlight. They speak cautiously, dress conventionally, and try to blend into the crowd.

Eliciting information from worriers is easier than you might think. Create the impression that whatever they say is no surprise. React calmly and blandly, pretending that you know much more about the subject than you do ("Oh, of course."). Once they feel as if they aren't sharing anything you don't know, they will begin to open up.