Apart from common enemies and survival, what are the other factors that make players collaborative in an open world game?
For example: In Rust(https://rust.facepunch.com), randomly spawned players tend to kill one another and loot items. In The Forest(https://endnightgames.com), players tend to collaborate to survive against mutants.
I read through this question, Designing fictional non-competitive games, but only sports are mentioned mostly. Environment vs Players is also a factor mentioned in there.