Conversation so far:
What was DJ Kook Herc's the break?
DJ Kool Herc developed the style that was the blueprint for hip hop music.
What did the break consist of?
Herc used the record to focus on a short, heavily percussive part in it: the break.
Did people like the break?
The break was the part of the record dancers liked best

Question: How did it lead to a cultural evolution?
Self-contained rewrite: How did the break lead to a cultural evolution?