What does it mean that schemas about other people?

Your default assumptions about human nature shape every interaction.

Example: You hire a junior engineer who misses a deadline. Your schema about people determines what happens next. If your default model says 'people are lazy unless pressured,' you increase oversight and check-ins. If your model says 'people want to do good work but sometimes lack context,' you ask what blocked them. Same person, same missed deadline. Completely different intervention — and completely different trajectory for that engineer's development. You didn't respond to the person. You responded to your schema about the person.

Try this: Pick three people you interact with regularly — a colleague, a family member, a friend. For each, write down your default assumption about their motivation. Not what they do, but why you assume they do it. ('She argues because she needs to be right.' 'He's quiet because he doesn't care.' 'They volunteer because they want recognition.') Now ask: what evidence would change this assumption? If you can't think of any, the schema is functioning as an unfalsifiable belief — and it's running your relationship.