The brain looks for rhythmic and melodic resolution, and in lots of popular music – and popular classical music – themes tend to resolve in 4, 8 or 16 bars. How

The brain looks for rhythmic and melodic resolution, and in lots of popular music – and popular classical music – themes tend to resolve in 4, 8 or 16 bars. However, in some Latin American music, themes continuously develop, telling a story with "jazzy" chords that don't completely resolve immediately, and in other music, such as some classical music and even black metal, the challenge is for the brain to be willing to go into unresolved dissonance; one famous example is the Tristan chord, where the resolution takes rather literally the time of a whole Wagner opera. It would be interesting to see a study on the correlation between musical taste and delayed gratification in general, though of course different situations require different musical choices – one wouldn't pick something that requires mental focus when cleaning the house.