Jack and his "savage" followers, like Roger, for example, all embody the id. They act on their basic, brutish impulses and do not consider the consequences of them, especially when they relate to the other people around them. A good example of this would be when they stole Piggy's specs in order to have fire for themselves. They solely cared about what the specs could do for them, which is give them a cooking fire for their pig, and do not consider the fact that it would harm Piggy, since he would not be able to see at all, and they did not consider how doing that would likely prevent them from getting rescued, since there would be no signal fire. Later, when Piggy, Ralph, Sam, and Eric, go to retrieve Piggy's specs, Jack and his tribe exhibit no remorse for their actions, and end up just killing Piggy (and smashing the conch) when he speaks out against them, calling them out as savages. All of this points to their inability to judge right or wrong actions, since they largely act on evil impulses.  

 Ralph is the Ego in the story because he acts in rational ways, but he does not have a fully developed moral compass that points him clearly towards what is right and wrong. He seeks to satisfy his basic desires in a way that would be beneficial to the group in the long term. For example, he has a desire for comfort and safety. He satisfies this desire intelligently, by constructing shelters and making a signal fire, which later becomes a fire for comfort after Jack splits away from the group and forms his own tribe. However, Ralph did have some actions that demonstrated that his moral compass was not entirely developed. For example, he was excited when he had stuck the pig a little when he was hunting with Jack and the other hunters, and he also derived some pleasure from making fun of Piggy, especially in the beginning. 

Simon exhibits the superego because of his wise and generally kind actions. For example, when Piggy was not given a piece of meat when the hunters first killed a pig and roasted it on the mountain, he gave his portion to Piggy, simply because he felt it was the kind and right thing to do. Then, when all of the boys started obsessing over the idea of the beast, Simon had the insight to say that the beast was inside of the boys, which can be interpreted as acting solely upon the id in Freudian terms. Finally, right before he dies, Simon had the sense to go up the mountain to really see what the “beast” is, where he discovered that the “beast” was simply just a dead man in a parachute. Simon is later killed before he can even communicate this discovery to the group, but Simon’s wisdom and his intelligent actions all point to his developed moral compass in the superego.  

Piggy exhibits the superego but is a little closer to the ego than Simon is. This is because most of his decisions are not entirely driven by an attitude of moral correctness, but also a desire for self-preservation and to do the rational thing. For example, when Ralph considers giving up chieftainship, Piggy warns against it, not only because it would cause their scantily organized society to collapse, but also because he would inevitably be hurt or killed. However, Piggy evolves more and is consistently the voice of reason in the group. Right before his death, he asks the tribe what is better, savagery or civilization. This demonstrates his superego because he has the inherent values of society that were instilled in him, and his attitude towards what behavior is right and wrong.

However, Ralph certainly hoped in the beginning that life on the island would resemble Rousseau's theory, which is that people in a state of nature would simply act in their own interests and according to their urges, but with compassion. However, this did not happen. Ideally, their society might have been Lockean, which would mean that Ralph's society would respect natural rights of life and liberty (at least, since none of the boys really have property).