The "Upper Paleolithic Revolution" hypothesis proposes that around 50,000 years ago, there was some sort of a qualitative jump in human behavioral complexity, based on the fact that around that time we start seeing clear evidence of cultural and symbolic behavior such as rock art and burial rituals, and also of a period of rapid innovation in toolbuilding. Critics of the hypothesis counter that the apparent jump could just as well be merely a selection effect caused by the scarcity of evidence.
https://en.wikipedia.org/wiki/Behavioral_modernity