Question

When we refer to someone's intelligence quotient as if it were a fixed and objectively real trait such as height, we commit a reasoning error called?

Answer 1

I believe the answer is: Reification

Reification refers to the process of fixating certain attributes to another attributes without proper proof.
In the example above, the reification happen after we fixate intelligence attribute with height even though intelligence are purely influenced only by genetics, nutrients, and environment.