Our weapons were our instruments

Given the fact that nearly everyone engages in deception at least occasionally, how can we recognize such actions? 

1. Microexpressions: These are fleeting facial expressions lasting only a few tenths of a second. Such reactions appear on the face very quickly after an emotion-provoking event and are difficult to suppress. As a result, they can be very revealing about others’ true feelings or emotions. 
2. Interchannel discrepancies: A second nonverbal cue revealing of deception is known as interchannel discrepancies. These are inconsistencies between nonverbal cues from different basic channels. These result from the fact that people who are lying often find it difficult to control all these channels at once. For instance, they may manage their facial expressions well, but maybe have difficulty looking you in the eye as they tell their lie.
3. Eye contact: Efforts at deception are often revealed by certain aspects of eye contact. People who are lying often blink more often and show pupils that are more dilated than people who are telling the truth. They may also show an unusually low level of eye contact or -surprisingly- an unusually high one as they attempt to fake being honest by looking others right in the eye.
4. Exaggerated facial expressions: Finally, people who are lying sometimes show exaggerated facial expressions. They may smile more - or more broadly - than usual or may show greater sorrow than is typical in a given situation. A prime example: someone says no to a request you’ve made and then shows exaggerated regret. This is a good sign that the reasons the person has supplied for saying “no” may not be true.