Listen to the loudspeaker as you walk past a store or some such place where the radio is set to a current-pop-hits station. Dr. Boli does not suggest that you spend a long time listening, but just enough time to confirm his observation that current popular music is obsessed with the first three notes of the diatonic scale.

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.