Throughout the novel, the characters seem like real boys rather than allegorical representations of vices and virtues. However, the boys' traits and actions stand in for behaviors and tendencies that Golding believes naturally occur in any group of humans. In this way, the boys' makeshift society on the island can also be read as an allegory for human civilization as a whole, with all of its downfalls and potential for brutality and malevolence.
Piggy, for instance, is intelligent but weak, and in this way he represents people who are marginalized or victimized in society. The boys would benefit from listening to him more often, but they don't because he cannot command their respect. Simon, meanwhile, can be read as a Christlike figure who communes with the spiritual world of the island and confronts death, including eventually his own. And Roger seems to represent a cruel element of human nature that loves inflicting pain on the innocent.
Other elements of the story, such as the conch, the pig skull, and the fires, play both literal and allegorical roles in the story. The conch is how the boys call their original tribe together, for instance, but it also comes to symbolize civilization's fragility.