> You're saying that the curiosity is "natural" hence one is either born with it or not.
Why does curiosity being natural necessarily mean some people are born without it? It could also mean everyone (or every average human) is born with it, and overtime it gets pushed out of people.
I think the case you mentioned is explained by an idea covered in attachment theory. Children explore when they feel safe and secure. Safety and security come from the caregivers, the parents. When that is absent, because the parents' emotional state makes the children feel insecure, then the children are restrained by their own emotions.
Why does curiosity being natural necessarily mean some people are born without it? It could also mean everyone (or every average human) is born with it, and overtime it gets pushed out of people.