>some examples of ways they were superior in intelligence?

None. Because no civilization is superior in intellect to another.

When talking about "primitives" people take for metric: knowledge of technology, complexity of political structure (which are usually way more complex than what outsider see). They say they are less intelligent because they assume that if they don't have steel/guns/wheel/boats/kings/huge buildings, it's because they can't, as if anyone anywhere could come up with those on the fly. While in reality we only develop those technologies if we have the need to. You need specific circumstances, not a bigger brain.

Societies are not more intelligent nowadays that they were 15 000 years ago.