For instance, in both fake and real smiles, the zygomaticus major muscle pulls the cheeks upward. However, with genuine smiles, the parts of our brain that process emotion also raise the orbicularis oculi and pars orbitalis muscles, which raise the cheeks and cause the eyes to crinkle.
Looking back at the test faces, I noticed that sometimes the deceitful smilers also seemed to have squinted or creased eyes. The key is to look at the "eye cover fold," which is the skin between the eyelid and the eyebrow. With real smiles, this area moves downward and the eyebrows lower a bit as well. It's hard—if not impossible—to consciously try to do this. Quiz: Do You Fall For Bad Boys?
Body movements can also hint at a liar. In a 2003 study on cues to deception, UC Santa Barbara psychology professor Bella DePaulo found that liars are tenser and fidget more than those who are telling the truth.
According to an article in the Journal of Accounting by Joseph Wells, founder of the Association of Certified Fraud Examiners, this may be a result of our innate "fight or flight" system, which triggers movement in times of stress. He contends that some people may change positions when asked difficult questions or in the middle of a lie. Thompson also notes that sometimes liars cover their mouths when they are telling a lie.
DePaulo also found that liars are generally more unpleasant and complain more than non-liars do, although this is obviously a personality trait that some people have regardless of whether they're lying or not. 10 Quick Ways To Size Him Up
Studies have shown that liars also change their speech patterns and word choice. Liars will sometimes use distancing language, meaning they use fewer first person pronouns and more third person. A 2003 study by researchers at the University of Texas showed that in addition to using fewer self-references, liars also used more negative emotion words, such as "angry," "frustrated," or "fear."