What does your body language reveal about you at any given moment? Body language starts in the brain. For example, when your blood pressure rises (as may happen if you are telling a lie), capillaries in your nose can dilate, allowing more blood flow. Lying can also trigger an adrenalin rush with similar results, according to psychologist Michael Cunningham, a professor of communication at the University of Louisville. Increased blood can make your nose feel itchy, which prompts you to touch it. (Typically you rub your nose more vigorously when you have a genuine nose itch unrelated to lying.) If the person you are talking with knows this piece of brain trivia and you are touching your nose often, it might suggest deception. An exception might be a sociopath whose brain fails to register truth from fiction, so blood pressure might not rise or there may be no adrenalin rush.