You know them. They look just like us. They eat the same foods we eat, wear the same clothes we wear, and sleep under the same stars we sleep under—you could even be sleeping next to one of them and not even know it. You’ve seen these people in action, working their nefarious brand of charm, wit, and charisma. They operate largely unnoticed—until they don’t, at which point it’s usually too late, because they’ve already insidiously laid claim to your faith, your livelihood, or maybe even your life. No, we’re not talking about Canadians. We’re talking about sociopaths, those creatures who, through their grand schemes of contrivance, manipulation, and deceit, seek to undermine the very fabric of it all because, well, they can.

Clinical psychologist and former Harvard Medical School instructor Dr. Martha Stout has spent a good portion of her working life attempting to crack the mystery of what makes someone a sociopath—she says it has something to do with having a conscience, or not having one. Stout has even authored a book on the subject, The Sociopath Next Door, and is at work on a sequel, tentatively titled Conquering the Sociopath Next Door: Courageous Resistance to Lies, Scams, Mind Games, and Murder, which is expected out next year. Here, she offers a thumbnail sketch of the nature of sociopathy, and how regular folks can best prevent themselves from falling prey to the dangerous games that sociopaths play.

KATE SIMON: Why did you title your book The Sociopath Next Door?

MARTHA STOUT: The Devil You Know was the working title and then Kris Puopolo, my editor, called up one day and said, “Do you remember when you called it The Sociopath Next Door and you thought you were kidding? Well, we really like that title.” I think it’s more immediate and it captures what the book is about . . .

SIMON: Well, initially the title is scary. Like, “Ooh, Ted Bundy is next door!” Your point is that one in 25 people in North America is a sociopath—that it could be your next-door neighbor, your teacher, your co-worker, your . . . husband. Sociopathy is more prevalent than schizophrenia or anorexia.

STOUT: Right. It’s a much more common thing than most people realize.

SIMON: Explain the characteristics that a sociopath exhibits.

STOUT: Okay, the central trait of sociopathy is a complete lack of conscience, which is very difficult for most people to get their heads around, because those of us who do have a conscience can’t really imagine what it would be like if we didn’t. Most people think that deep down everybody has a conscience, and it turns out that’s just not true. So if you don’t have a conscience, what is your behavior like? Apparently, if you don’t have a conscience, if you don’t really . . . love, then the only thing that’s left for you is the game—it’s about controlling things.

SIMON: Manipulating people.

STOUT: Yes. Sometimes it doesn’t even have to be a large manipulation. And sociopaths are just like everybody else in that some of them are really brilliant, some of them are really stupid, and most of them are somewhere in between. Another thing I should point out is that sociopaths are not usually physically violent. A typical sociopath never kills anybody and doesn’t look like Charles Manson—they look like you and me and everybody else. You’re not looking for someone who’s recognizably evil or scary-looking, but rather someone who looks normal. Another lynchpin is dishonesty. Lying for the sake of lying. Lying just to see whether you can trick people. And sometimes telling larger lies to get larger effects. The other thing that needs to be stressed is that sociopaths are often extremely charming. They are people who are better than you and me at charming people, at being charismatic. I’ve heard this more often than I can count: “He was the most charming man I ever met,” or, “She was the sexiest woman I ever met,” or, “The most interesting person I ever met . . .” That’s because to learn to be charming is fairly easy—you can teach somebody to be charming and to learn human emotions—or to learn the behaviors that go with human emotions. A sociopath, a smart one, will study the way we emote, and will learn how to do that quite effectively.

SIMON: Is there a particular type of person that a sociopath picks out to manipulate?

STOUT: Well, the perfect victim, from the sociopath’s point of view, is the person who is smart enough and capable enough to do him some good in the world and who is also fun to manipulate. How much fun is it to manipulate someone who is stupid and incompetent? Another good person to manipulate is someone of high character, because that is also fun for the sociopath. On the other hand, the sociopath doesn’t want this person to be so savvy that he or she will immediately see him for who he is. He wants the person to be easily enough fooled to stick with him. This can be accomplished by looking for someone who is very, very loyal. Most of us consider loyalty to be a very positive trait—and it is a positive trait. But it also blinds people to some of the traits of the person they’re loyal to.

SIMON: One idea in the book is that we shouldn’t confuse fear with respect. Can you elaborate?

STOUT: It’s kind of wired into us that when someone is harsh to us, or when somebody makes us feel bad, that in some way they’re better than we are. A reviewer who says mainly negative things is going to be perceived as more intelligent by the audience than the person who says positive things. That’s just human nature. And someone who makes us afraid encourages a sense of respect, and that’s unfortunate because somebody who makes you afraid is very likely to be doing it just for the purpose of making you afraid, and is not the kind of person that you want to respect at all.

SIMON: In The Sociopath Next Door, you list 13 ways to deal with a person one assesses to be a sociopath. Can you share some?

STOUT: If you have reached the point where you’re certain that this person has no conscience, or is in it to win rather than to love you, then the very best thing you can do is to get away. That’s a very hard lesson to learn, and, furthermore, it’s not always possible.

SIMON: Are sociopaths afraid to be alone?