On what basis?
Exactly. Same back then as today.
An insecure cave person would be protective of their cave painting turf. A well-adjusted cave person (also likely more talented) would be sharing ideas and resources or have other work for/with them.
the concept is very new
Really? Curious that we know the author's name then… seems like… attribution?
Do you get angry if someone "steals" your programming techniques and ideas, and copies them into a new portion of the codebase?
I think all of this is very cultural.