is it human nature to conform?

It is human to conform. Conforming is a hell of a lot easier than non-conformity. To stand up for your beliefs in the face of overwhelming opposition is heroic but it also exacts a heavy price. Consider Simon, Ralph, Piggy and the twins towards the end of the novel. Even Piggy muses about joining Jack's tribe. He laments that at least there will be safety in numbers and plenty to eat. Still, they refuse to conform. By not conforming they stand up for their beliefs but are systematically destroyed for their heroism.