Humans are constituted for life in a polity, so institutions are not an imposition on human nature but an expression of it.
Aristotle's Politics. The claim is stronger than sociability: humans develop the capacities that make them human only within a polity, so institutions are constitutive rather than imposed.
In practice
- A person who moves to a country where they know nobody finds that their competence, their standing and half their preferences were held by the place they left.
- A child raised without any social institution does not become a purer version of themselves, which is the empirical form of the claim.