The answer is probably language. Before advanced language was developed, there wasnโt a good way to pass along any knowledge that was gained by an individual.
Letโs carve our memes into stone and bury them for future archaeologists.
I thought it was because proper farming.
Like being able to support larger groups of people, where individuals could specialize in other things than hunting, gathering and whatever else was keeping the early humans busy.
On the other hand Iโve heard weโve been possibly farming long before 10,000 BCE.
Language is much older than just 10k years. Thereโs a few reasons to think that language might have developed with erectus, which could make language 10x older than the โhuman specieโ, according to anon.
Thatโs why i said advanced language. Lots of animals have language. Crows have language
Usually the distinction is between โadvanced communicationโ which some animals display, and โlanguageโ, which only humans have.
Whether you want to call it language or advanced language, what we do today is way older than 10k years. There are stories that have been dated to 100k and if the arguments about erectus are correct, then what you call advanced language is probably 2m+ years old.
Language probably predates Homo Sapiens as our close relatives such as Homo Neandertalensis and Homo Denisova also had adaptations for articulated speech.
https://www.nature.com/articles/s41559-021-01391-6
Beside, populations today that have never had agriculture or traits we associate with civilization and who live secluded, like the North Sentinelese, all have languages.
I think itโs best explained by environmental factors, rather than something interior to humanity. After all, most of humanโs existence was during the Pleistocene, but all recorded history is within the Holocene (except now weโre entering the Anthropocene). Many modern studies account for the climate shifts to explain the development of agriculture:
https://www.pnas.org/doi/pdf/10.1073/pnas.1113931109
https://journals.sagepub.com/doi/10.1177/0959683611409775
Most traits we associate with civilization are linked to agriculture and sedentary.
As IoaExMachina correctly highlighted, language predates those 10k years.
For reference, Proto-Afro-Asiatic (ancestor of Egyptian, all Semitic languages, Amazigh, plus a lot others) is believed to have been spoken 12k~18k years ago. Soโฆ like, it was already old back then, and yet it has modern descendants.
And the role of language is probably not just communication, itโs also to formalise thought. Itโs easier to think with language than without it, and you can reach more reliable conclusions.