In chapter 5, Jack cries:

“Bollocks to the rules! We’re strong—we hunt! If there’s a beast, we’ll hunt it down! We’ll close in and beat and beat and beat—!”

This bold assertion of violence excites the listening boys, and they respond approvingly, "full of noise and excitement, scramblings, screams and laughter."

When the novel opens, choir leader Jack is angry and sulky because he is not elected leader. At that point though he shows a willingness to follow civilized rules and norms. As time goes on he realizes that giving into his lust for violence and rule-breaking is a potent source of power. He can gain followers and do what he wants the more savage and autocratic his behavior becomes. He recognizes that in the absence of adult authority, there is no one to put a stop to his violence.

Jack, the Hitler figure in the novel, abandons logic, reason, and the rule of law. Instead, he appeals to the most atavistic, "primitive" desires in the boys and encourages them to let their ids run loose. His society of hunting, violent ritual, cruelty, sadism, wild dancing, and body painting is so alluring it wins out over Ralph and Piggy's less entrancing world of rationality, foresight, and decency. Left to their own devices, the boys simply follow the one who allows them to give into the impulses of the moment.

By the end of the novel Jack's leadership set the island on fire, which, ironically, catches the attention of the British ship that comes to rescue them.