A The truth is we’re not very good at detecting lies, especially with people that we don’t know well. There are signs from body language and speech that might indicate that someone is lying, but none of them alone are 100% reliable. However, if you keep that in mind, the following tips might be useful.
B Some believe that avoiding eye contact is a sign of deceit, and there might be some truth to that, as it can feel uncomfortable looking at someone you’re lying to. But it could also mean that a person feels uncomfortable for some other reason – perhaps they are bored or anxious, or maybe they don’t want to be talking to you. And, as Professor Robert H Frank says, eye movement is easy to control, so people who are good at lying might find it easy to maintain eye contact.
C A person touching or covering their mouth or eyes might be a more reliable sign of lying, according to Vi-An Nguyen. Taking ideas from a book by former CIA officers, Nguyen explains that people have a tendency to want to cover a lie, which means that a liar might move their hand in front of their mouth when being dishonest. Similarly, they might cover or even close their eyes when answering a question, as if, unconsciously, they don’t want to see the reaction to lies they are telling, she says.
D Throat clearing or swallowing before answering a question could be another sign that someone is about to lie, Nguyen says. One reason for this is that the anxiety a person feels when telling a lie can cause the mouth or throat to become dry. Frank adds that in some ancient societies, a test to detect lying was to place some rice in a person’s mouth; if it came out dry, he or she was thought to be lying.
E A problem with these signs is that, although they likely indicate that the person is experiencing some discomfort, there are many reasons other than lying that someone might feel uncomfortable. Ex-FBI agent Joe Navarra says that touching the face, clearing the throat, and covering the mouth are what he calls self-soothing behaviours – things people do when they feel uncomfortable or anxious, and lying is only one of things that might be causing the discomfort.
F Psychology author Kendra Cherry suggests that some more accurate signs of lying are connected to the speech itself. In an article for Very Well Mind, she explains that someone being vague (leaving out important details), seeming unsure, or thinking too hard might indicate that they’re being dishonest. And Frank adds that person’s voice tends to get higher when they’re lying, possibly connected to fear of being found out; but again, there are other reasons a person’s voice may get higher.
G Forensic psychologist Carol Dando agrees that focussing on what is being said is more useful for detecting lies. She says that questioning techniques, such as using open questions, listening more than speaking, and asking questions that you already know the answer to, can be effective in spotting lies. She adds that clarification questions are useful, as liars might find details difficult and might contradict themselves. Lying is more mentally demanding than telling the truth, she explains, and using specific questioning techniques will cause the liar to use even more mental energy, which means signs of lying are more likely to appear.
H Although we’re generally not very good at detecting lies, we are much better at it when it’s someone we know well, Dando says. She explains that when someone we are close to is lying, it might be easier to notice that they’re behaving differently or that something doesn’t feel right. And if you have a feeling that something is wrong, it might be wise to trust your instincts; Cherry explains that we are often correct when we have a sense that someone is lying, but looking too hard for signs of deceit can interfere with this and actually make it more difficult to tell whether the person is being honest or not.