The answer is "facial feedback" effect.
The <span>facial feedback effect theory explains that when someone imitates some facial expressions it actually affect his or her emotional response, for example if during an even one person who is not enjoying the event is forced to smile and laugh, eventually he will find the even more joyful and might start enjoying the event.</span>
The words of Thomas Paine in the phamplet <em>American Crisis </em>were enough to keep the revolution going and muster the troops under George Washington's command in 1776. In 1777, when they were suffering heavy losses due to the winter at Valley Forge, it was loyalty to the Patriot cause and to George Washington while training and doing drills that kept the troops busy and allowed for them to leave Valley Forge in 1778 more disciplined and spirited.
