Monolithization

To see people as if they were not individual persons, but rather specimens of a monolithic category. For example, understanding statistical differences between groups as if they were categorical differences. As if a certain trait being somewhat more common in one group (compared to some other group) would mean that “the people in that group has that trait”. (In Swedish: monolitisering)

When applied to a category of human beings, this is a facet of categorism.