How to tell if someone is lying? One way is excessive blinking and winking. Lying creates a lot of stress on the body. One of the most noticeable effects is a sudden increase in a dishonest person's blink rate. As the body goes through its efforts to destress itself, certain areas of the body may start to feel dry. For the same reasons some liars may lick their lips compulsively, others may blink their eyes in order to restore lubrication. Honest people don't experience these effects of stress, so their blink rate rarely changes. When determining if a speaker is being truthful or not, observe their blink rates before, during and after their speech.