In Chapter 10 of Lord of the Flies, why does Jack attack Ralph's group?
Beginning in Chapter One, Jack has desired power; his pride is clearly hurt when the boys vote for Ralph as chief, and he runs off. But, soon, he finds his niche as the leader of the hunters, for not only does Jack have a sense of power in tracking and killing the feral pigs that roam the island, but by being the meat provider, he can wield power over the other boys. In Chapter Three, Jack tries to explain his compulsion to track and kill to Ralph, but he cannot find the words. At any rate, the primal urge to hunt and kill exists strongly in Jack, who regresses in his behavior to a savage who paints his face. Golding writes in Chapter Three that Ralph and Jack are "two continents of experience and feeling, unable to communicate."
They are "baffled in love and hate." For, Ralph represents the civilized values as he prioritizes building shelters and maintaining the rescue fire while Jack encourages the painting of faces, hunting, and ritualistic, brutal dancing and beating upon others. In Chapter Nine, Jack feels his superiority as a hunter who brings meat to the others. He stands over the group that cooks the meat, waving his spear and giving orders. Then, after having witnessed Ralph's loss of control over the boys as they all flock to the feast, and having stolen the fire, not to mention having caused the death of the prophetic Simon, Jack feels that he has more control over the boys than Ralph. Therefore, he and his followers attack Ralph, Piggy, Sam and Eric; they beat up the boys, but evidently they have mainly come for one thing: Piggy's glasses.
The chief led then, trotting steadily, exulting in his achievement. He was a chief now in truth, and made stabbing motions with his spear. From his left hand dangled Piggy's broken glasses.
Jack now holds the symbol of reason and the key to igniting a rescue fire: Piggy's glasses. By stealing these glasses, Jack has stripped Piggy of much of his power.