Look for a fake smile. Real smiles and fake smiles look very different upon closer inspection. A fake smile is often limited to the person’s mouth, while they genuinely smile with their eyes, cheeks and whole face. If the person seems to be fake smiling at you, they may have something to hide. The smile is an attempt to reassure you that all is okay.
You can practice spotting the difference by comparing candid photos of smiling friends or family to staged photos with “say cheese” smiles.


See if their head shakes “no” when they say “yes” — or vice versa. Untrained liars often betray what they’re saying with unconscious head movements. Watch them from the neck up as they tell you a suspected lie, and see if the “yes” nod or “no” shake matches what they’re saying.
For instance, if your boyfriend declares that “No, of course I wasn’t out at the club with my ex,” but he subtly nods while saying it, you may have reason to be suspicious.


Note if they look away from you frequently. While it doesn't mean that the person is lying, you can use broken eye contact along with other observations to make a judgement. Eye contact can be difficult for liars to keep. People can react to this uncomfortable feeling by looking away frequently. Or, they may overcompensate by staring straight into your eyes the whole time. Eye contact in either extreme may signify a lie.
Some people aren’t good at maintaining eye contact under normal circumstances, of course, so compare them to their typical mannerisms.
Additionally, people also break eye contact often when they are trying to remember something or are accessing their long term memory.

Watch for changes in the person’s behavior. If a person is normally energetic and loud, they may get quiet when they try to lie. Or, if they’re normally calm and quiet, they may be anxious and restless when lying. As with eye contact and other mannerisms, compare what you see to what you typically observe from this person.
Keep in mind that these changes can come from a stressful state. A student being accused of cheating on a final exam may respond in out-of-character ways due to stress, but still be innocent.
Look for fidgeting, such as playing with hair or pressing their fingers into their lips.
The individual may also start to be vague, providing very few details. This is especially concerning if they normally provide a lot of information.
They may ask a lot of questions instead of answering yours.
If you challenge a story they're telling, they may omit specific details or act unsure. You may even be able to detect a change in their voice.


Keep track of distancing language. Someone who's lying may unintentionally try to distance themselves from the words they use. Instead of using the words ‘I’ or ‘me,’ they might overuse ‘they,’ ‘we,’ or ‘theirs.’ This is an indication that the person subconsciously wants to separate from the lie.
They might do the same with other people as well. For instance, you might ask “Did you kiss Joe yesterday?” and have your girlfriend reply “Why would someone kiss that guy?”
Pay attention to idioms. If the person keeps using phrases like “To tell you the truth,” or “I honestly,” they may be lying. Unless these are idioms that the person uses regularly, this affirmation of the truth can be a sign they are actually lying. It is an attempt to convince you, and themselves, of the lie

A similar example might be: “I swear I didn’t spill the paint, Mom — you have to believe me!”
Be suspicious if the person is unusually talkative. Many people talk more that normal when they’re lying. They will use extra words to keep you distracted from what they are actually saying. Or, they may tell you needless specifics to convince you of the richness of this “truth” and fill in gaps with excessive detail. Whether by plan or unconsciously, they hope this will allow them to get by with the lie.


For example, if someone says “I went out to the park on the far side of town to take a nice relaxing walk,” instead of “I took a walk in the park,” they may be lying about their whereabouts.
In practiced liars, however, the opposite can be true. They may only offer the very bare bones of the story. Once again, watch for deviations from normal behavior patterns.


Review their story for inconsistencies or contradictions. If the story is unbelievable, that could be a clear sign of a lie. Also, if the story seems to have small details that don’t add up, it may be fabricated. These inconsistencies are a sign of an underdeveloped lie.

Think of how detectives on TV police dramas try to get suspects in the interrogation room to create inconsistencies in time or other details (“How could you have been in the restaurant at 10:45 and at home across town at 11?”).