More here, if you’ve the stomach for it.
As the games got more complex, so did the audio, and the theories behind it. A loop, or short, repeated section of audio, acts as a recurring cue. Dissonant sounds communicate failure, while consonant ones—think of the sympathetic vibrations of Super Mario Bros.—encourage players to continue. The tones can even mimic human sounds—a modulating synthesizer approximates laughter, like the “wawawawawa” in Duck Hunt.