From: J. G. A. Barbedo and A. Lopes, “Automatic genre classification of musical signals,” EURASIP Journal on Advances in Signal Processing, 2007.
The authors specify the meaning of each of these labels. For instance, “Dance” music has “strong percussive elements and very marked beating.” Stemming from “Dance” there is “Jazz”, “characterized by the predominance of instruments like piano and saxophone. Electric guitars and drums can also be present; vocals, when present, are very characteristic.” And stemming from “Dance,” stemming from “Jazz,” there is “Cool”, a “jazz style [that is] light and introspective, with a very slow rhythm.” The genres “Techno” and “Disco” — which both emphasize the importance of listening with your body and feet — do not stem from “Dance,” but instead from “Pop/Rock,” “the largest class, including a wide variety of songs.”
Props to the authors for attempting the impossible, but any taxonomy of music genre must be broken from the very first stem. Genres are not like species, and cannot be arranged like so. (On the plus side, it appears that to differentiate introspective music from non-introspective music requires only four spectral features computed over 21.3 ms windows.)