The term was coined by journalist walter lippman (1922), who referred to these phenomena as "the little pictures we carry around in our heads."

The answer is: Stereotype

Explanation:

Walter Lippmann was an American reporter, writer, and political commentator. He coined the term stereotype and introduced the concept of Cold War.

Walter Lippmann described stereotype as the little pictures we carry around in our heads. It refers to an over-generalized belief about a particular group of people. It is described as an expectation about each individual of a group.

an informal structure in a bureaucracy would be something like so-called "office politics". where there's a formal structure set up for the organization, but then an informal subculture as well that has a way of organizing the bureaucracy further. this can be positive because it sets up an added degree of organization, albeit informal, within the bureaucracy.