The next time you are talking with someone and it’s important he or she knows you are telling the truth, turn your palms up. It subliminally says, “I have nothing to hide.” Police interrogators are sensitive to subtleties like this.
Keeping your palms up also express warmth and and acceptance of the other person. Often religious figures are depicted with their arms open and their palms facing up.
Lastly, a tip for the ladies. Sitting at a table, if you rest your chin on your knukles with your palms facing a man, it signals “come hither.” Knuckles express “go away.” In fact, whenever speaking with anyone, give yourself a hand check until “open palms” becomes a natural habit.