Now ask yourself why that should be. Formulate a hypothesis, and see if you can accumulate enough evidence to elevate it to a theory. Dr. Boli will start the game. It is his hypothesis that sticking mainly to the first three notes of the scale makes composing a serviceable melody the least possible effort, and causes an occasional foray up to the fourth or even the fifth to strike the dulled senses of the casual listener with an unexpected thrill.