By Chris Simmons
People often hide their mouths or eyes when they are attempting to deceive. They accomplish this by shielding their eyes or mouth with the open palm facing inward. When blocking the mouth, their hand gestures will close enough to their face to intentionally conceal your view of their mouth but far enough away so as to not obstruct their words. These gestures aid the deceiver because it makes them feel as if they are literally hiding the lie. When they use their hands to cover the eyes, its because they do not want to make eye contact, nor do they want to see your reaction to their deceit. Additionally, an oft-seen variant of eye-shielding is simply an extended closing of the eyes.
Conversely, when a person physically covers their mouth with their hand, it generally indicates a strong desire not to speak, rather than intent to deceive. However, the physical blocking of the mouth also suggests the person prefers not to speak because you’re not going to like what they have to say. As such, the covering is an avoidance technique used to prevent an uncomfortable situation.