How does William Golding explore human brutality in 'Lord of the Flies'?

Character juxtaposition: Golding juxtaposes the characters of Ralph and Jack in order to demonstrate man's capacity for brutality and cruelty. Ralph's actions in the first half of the novel are guided by notions of the 'adult' world the children come from - his leadership is built on the key concepts of democracy, order and equality. These concepts are rejected by Jack, who allows himself to be guided by primal instincts. This manifests in a dictatorial leadership style marked by savage violence. During the novel's second half, we see Ralph's leadership style begin to unravel as he participates in the violence which eventually leads to Simon's death.
Language: the language used by Golding evokes the boys' descent into primal violence. The language used to describe Ralph in the novel's final chapter is particularly significant. Golding uses animalistic verbs and imagery ('launched himself like a cat', 'snarling') in order to convey the full extent of Ralph's descent.