According to most economics textbooks, human beings are super-rational creatures who know what is in their own best interests and always act accordingly. When making a decision to buy something, the rational consumer will evaluate all the possible alternatives before making a purchase, having already conducted research on the state of the market. They would not buy something on the spur of the moment, or on the recommendation of a friend. Nor would a rational consumer by unduly influenced advertising or a brand name in making purchasing decisions.