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Psychological Projection is broader than just "everyone thinks and acts like me"
From the description: "a character projects their own character traits, emotions, or desires to another character by presuming they feel or think the same as they".
This would be for a character lacking those traits but still ascribing them to the other person, based on their own prejudices.
For instance, Bob is English and very generous with his money. But he believes the Thrifty Scot trope is an accurate reflection of reality, and so is amazed to find out that his Scottish friend Alice actually gives her employees regular raises.
Perhaps I should correct myself: Psychological Projection's name is broader than just "everyone thinks and acts like me"
But okay, I do know the correct term for your question: Stereotyping
The "This is usually done unconsciously and never explicitly stated by the character, which can make it hard to notice. But if a character presumes something about another without having any reasons to think so and the presumption has something in common with themselves, they are probably projecting." part is also important in this.
Sometimes the projection can be more subtle- Say, in the second example, Carl is an engineer and on the weekends he's building Homemade Inventions; he can't imagine someone's job not being the center of their entire life.
Start on Stereotype and move from there? If a character has trouble imagining other people are not like them, that's immaturity, so Manchild maybe?
Edited by Veanne
Similar to Psychological Projection, but instead of "everyone thinks and acts like me", it's "everyone thinks and acts the way I think they do". Basically, when Bob needs to put himself in Alice's shoes, he uses the flanderized (often insultingly so) version rather than his own viewpoint, and is just as wrong.
e.g.