In Lord of the Flies, it is dubious whether Roger has possessed any civility at all. For, in Chapter One, he is described as a
slight, furtive boy whom no one knew, who kept to himself with an inner intensity of avoidance and secrecy.
Roger, the"dark boy," then appears in Chapter Two to say that there has been no trace of a ship. "Perhaps we'll never be rescued," he says. Then, in Chapter Four he and Maurice come down out of the forest and he leads the way through the sand castles that the littl'uns have made
kicking them over, burying the flowers, scattering the chosen stones....Only Percival began to whimper with an eyeful of sand and Maurice hurried away. In his other life Maurice had received chastisement for filling a younger eye with sand. Now, though there was no parent to let fall a heavy hand. Maurice still felt the unease of wrongdoing....He muttered something...and broke into a trot...Roger remained, watching the littluns.
When Henry wanders off along the beach, Roger follows him, hiding beneath the palms. Henry goes to the beach and busies himself along the water's edge, playing with the "creatures that lived in this last fling of the sea." Roger waits, at first hidden, then he comes out in full view. Then, he looks along the beach and sees that the others have moved on. From above he
stooped, picked up a stone, aimed, and threw it at Henry--threw it to miss.....Here, invisible yet strong, was the taboo of the old life. Round the squatting child was the protection of parents and school and policemen and the law. Roger's arm was conditioned by a civilization that knew nothing of him and was in ruins.
When Jack returns, Roger sees him, and "a darker shadow crept beneath the swarthiness of his skin." Jack does not notice his ominous appearance and tells Roger about the mask that he has made to disguise himself from the pigs. "Roger understood and nodded gravely."
At best, society conditioned Roger somewhat, but his innate nature is sadistic and given free rein, Roger is soon cruel and deadly.
Jack degenerates into savagery rather early on. In Chapter Two as the boys build the fire on the mountain, Jack and Ralph work together piling the branches and leaves. When they finish Ralph and Jack
looked at each other while society paused about them. The shameful knowledge grew in them and they did not know how to begin confession.
And, even Ralph, who realizes that the boys fall silent at the sight of the new rescue fire, feels the beginnings of
awe at the power set free below them. The knowledge and the awe made him savage.
Shortly after this, when the fire goes out of control and Piggy scolds. Jack turns on Piggy, "You shut up!" He wants to silence the voice of civilization. In Chapter Three, Jack hunts and the imagery of his description is that of animals: He breathes with "flared nostrils"; his eye seem "bolting and nearly mad"; when he rouses a bird who sends "echoes...by a harsh cry that seemed to come out of the abyss of ages," Jack shrinks with "a hiss of indrawn breath," and for a moment, Golding writes,
and for a minute became less a hunter than a furtive thing, ape-like....He passed like a shadow under the darkness of the tree and crouched....
After he returns to camp, Jack squats and Ralph peers into "Jack's fierce, dirty face." When he does kill a pig, he "hacks at it." In Chapter Four, Jack smacks Piggy's head, knocking off his glasses with an opaque look in his eyes.
In Chapter Five Jack takes over the meeting about the beast, shouting "Bollocks to the rules! We're strong--we hunt! If there's a beast, we'll hunt it down!...." He Jack exhibits no rationality; he suggests just brute, primitive force. Certainly after he and the hunters steal the fire in Chapter Eight, the descent into savagery accelerates as in Chapter Nine, the boys reveal in an feast described in terms of Roman orgiastic feast where Jack sits "painted and garlanded like an idol" and "piles of meat on green leaves near him."
I think this happens in chapters 11 and 12. In chapter 11, Roger dislodges the boulder that kills Piggy and crushes the conch shell. The conch shell is the symbol of civilization and when it is destroyed, the boys lose their civility. Roger is a bully from the beginning and has an uncontrollable lust for power and control. When the boulder comes loose, Roger is full of "delirous abandonment". Also, Roger is the one that forces Samneric to go over to Jack's gang. In Chapter 12, Ralph, the most civilized of all the boys, destroys the Lord of the Flies "totem" and after this, he is left all alone and at the mercy of the hunters. When the hunters go after Ralph, they have totally lost all semblance of civility.