Conventional wisdom holds that if you do someone a favor, that person is bound to like you more. However, research has revealed something entirely different: If you do someone a favor, it is you who will like that person more as a result.  But how can this be? The reason is that we justify our actions to ourselves by assuming that we did the person the favor because, well, we really like them. This phenomenon is called the Ben Franklin effect . Franklin once quipped, "He that has once done you a kindness will be more ready to do you another than he whom you yourself have obliged." Legend has it that Franklin, a Founding Father and renowned scientist, leveraged this discovery to win the favor of a rival Pennsylvania legislator by asking the legislator to lend him a rare book and then showering him with gratitude. It worked like a charm. According to Franklin,"When we next met in the House, he spoke to me (which he had never done before), and with great civ...