Encapsulation[0] might be the term you are looking for. Enforcing object boundaries makes it easier to reason about program behavior and enforce security guarantees.
If objects can only change their own data, then all change affecting the object is either caused by the object itself, or indirectly by another when information crosses the interface the boundary presents (e.g. a message was received).
Most languages use a memory model that doesn't even have the concept of access rights, everything can potentially affect anything else. If your program has to be secure, this is a nightmare.
[0] https://en.wikipedia.org/wiki/Encapsulation_(computer_progra...
Also interesting:
https://en.wikipedia.org/wiki/Message_passing
https://en.wikipedia.org/wiki/Capability-based_security