You say children learn abstract concepts in schools. Have there always been schools?
Where there is teaching, that is a school. You do not need to have a building proclaiming that. Till late even the mythological princes of India learned under the shade of Banyan trees in their Gurukulas. These Gurukulas were in forests. Children went there around the age of 8 (after the sacred-thread ceremony) and returned only after completing their education around the age of 24.
"A
gurukula or
gurukulam is a type of education system in ancient India with
shishya ('students' or 'disciples') living near or with the guru, in the same house. The guru-shishya tradition is a sacred one in Hinduism and appears in other religious groups in India, such as Jainism, Buddhism and Sikhism. The word
gurukula is a combination of the Sanskrit words
guru ('teacher' or 'master') and
kula ('family' or 'home')."
An ancient gurukula, a modern gurukula, Shahjahan and the Udaipur king embracing each other, Australian aboriginals
Yes... They transfer traditions and morals from one "tribe" to the next. That's how societies are built. I'm not sure when people start questioning their own communities but not all do. It's culture.
For example, the Greeks met at Olympus. Other regions have various fairs, regional markets, where different tribes meet, learn from each other. There was friendship ties between tribes, peace pipes, exchange of head-gear in India (Pagdi-badal) etc. Prince Khurram (later Mughal Emperor Shahjahan, who built Taj Mahal) had a 'pagdi-badal' with the Udaipur king when he was seeking refuge from his father. After that, they are considered as brothers.