[Question] Are Humans Fundamentally Good?

I’ve been doing some reading on political philosophy recently, with a focus on the works that influenced the founding fathers of the United States, and one of the ideas that comes up a lot is the idea of the social contract. One of the assumptions that drives this theory is that humans are not fundamentally good.

Are humans not fundamentally good?

In real live examples of anarchy, does society devolve because humans are not fundamentally good or because of some other reason?

I am an absolute newcomer to political philosophy so forgive me if I am misrepresenting social contract theory.