Civilizing words and music …

… The Golden Age Of American Song Was The Golden Age Of America - Forbes. (Hat tip, Dave Lull.)

The music of nineteenth-century American popular music, following familiar melodic, harmonic, and rhythmic patterns, was essentially free of surprise. The popular music of the 60s and afterwards would be increasingly harsh, dissonant, and aggressive. Both pre- and post-Golden Age popular song was generally simplistic in its melodies and harmonies, as well as in its lyrics. The Golden Age, by contrast to the periods that preceded and followed it, brought out a melodic invention, harmonic richness, and lyrical creativity that would not be seen before or afterwards. This, too, had its psychological effects.

Here's some evidence: