Quotation from a book’s author, Allan Pease

      The speed of some gestures and how obvious they look to others is also related to the age of the individual. For example, if a five-year-old child tells a lie to his or her parent, the mouth will be deliberately covered with one or both hands immediately afterwards (Figure 1).

The gesture of covering the mouth alerts the parent to the lie and this gesture continues to be used throughout the individual’s lifetime, usually varying only in the speed at which it is done. When the teenager tells a lie, the hand is brought to the mouth like that of a five-year-old, but instead of the obvious hand slapping gesture over the mouth, the fingers rub lightly around it (Figure 2).

      This mouth-covering gesture becomes even more refined in adulthood. When the adult tells a lie, his brain instructs his hand to cover his mouth in an attempt to block the deceitful words, just as it does for the five-year-old and the teenager, but at the last moment the hand is pulled away from the face and a nose touch gesture results (Figure 3). This gesture is nothing more than the adult’s sophisticated version of the mouth-covering gesture that was used in childhood. This is an example of the fact that, as an individual gets older, many of his gestures become sophisticated and less obvious, which is why it is often more difficult to read the gestures of a fifty year-old than those of a much younger person.