Chapter four is an interesting chapter in that it represents the boys losing their sense of what it means to be civilized. Roger is losing the restraints that society demands which allows him to throw the rocks, however he is still the tied to the traditions and restraints that is required by a civilized society. It is the latter that prevents Roger from actually hitting Henry. Golding suggests that there is a moment for all human beings when they have the capability of possessing both of these powerful conflicting emotions. Once the 'rules' are ignored, whatever those rules are, most of humanity will have trouble being 'human'.
Roger's throwing rocks at Henry seems merely like a boyish game at first. He is, after all, "throwing to miss" the child. The narrator tells us that Roger does not hit Henry because around him there circled a "taboo of the old life"--a life full of "parents and school and policemen and the law." These things have always kept Roger and the other boys in line. Roger, whose arm is "conditioned by a civilization that knew nothing of him and was in ruins," will not respect these taboos for much longer. He will become one of the most brutal members of Jack's tribe.
setting roger apart from the other boys, roger has sociopathic tendencies. Having someone dangerous on the island causes the sense of craziness and unrest to escalate.
It seems to me that Roger is becoming aware of his environment. He realizes that he no longer has to follow 'rules', and he sees that he can gain power if he acts as Jacks right-hand man.
Oh... and... Bush sucks!!!!!!!!!!!!!!!!