Learn how to use the interrogation technique to detect lies in this Howcast video about body language.
Essentially, lie detection is a two-part process. So what we’re doing is looking for non-verbals that are associated or correlated with the line. We’re looking for clusters of non-verbals as indicators of whether or not somebody may be lying or telling the truth. So it’s sort of like, you know, points we need to later address.
The second thing is interrogation. So essentially, what we have to do is interrogate the person. Have a back and forth discussion to determine what they do. You can’t just look at somebody and be like, "Boom. Point. Oh, they did this, they did that, they did this. They’re lying." You need to follow up more.
So when determining when someone’s lying, it’s a back and forth process. You need to be very open to seeing people’s non-verbals. But you also need to be able to interrogate them and ask them specific questions that, kind of, narrow in on it.
So like, one useful, like, interrogation technique is, like, if you see somebody’s non-verbally talking about a certain area. Talking about what happened Saturday night, and you’re not sure, like something’s up. What you’re going to do is "Okay, Okay. Forget it. Let’s not talk about Saturday night. Let’s talk about what are you doing tomorrow?" And you completely change the topic and see if they’re non-verbals change. And then, what you do is bring it back to Saturday night to see that, "Okay. There’s a difference between when I talk about Saturday night. There’s something about Saturday night that it means something." So that’s what you’re kind of looking for.