Ralph takes responsibility for his own actions as chief of the other boys on island. In the very beginning, Ralph actively seeks the role of chief, and later, he takes responsibility for that action by treating the job seriously and with dedication. The reader can tell that Ralph genuinely feels strongly inclined to model good behavior for the other boys in regard to following the rules as well as completing the chores that they had all decided upon. One such chore was building the huts for protection; Ralph emphasized the importance of having shelters for the littluns. Then in Chapter 3, the reader sees Ralph following through with this decision by being one of two remaining boys actually building the huts. The littluns are "hopeless. The older ones aren't much better. D'you see? All day I've been working with Simon. No one else. They're off bathing, or eating, or playing" (50).
Ralph clearly would much rather go play along the beach like the other boys, but he feels committed to take responsibility for his actions; he stays out in the sweltering heat and builds the huts, with only Simon for help.
Taking responsibility for your actions means that you acknowledge your role in an event or an occurrence and are prepared to make things right if they have gone wrong. There are a number of instances in Lord of The Flies where Ralph does exactly that.
Ralph makes himself available for election as chief at the beginning and accepts the role once he has been chosen. His acceptance obviously means that he has to lead the boys and make important decisions for them. He takes on this responsibility with aplomb. He soon allocates duties and tells Jack that he should be in charge of the choir. He then tells the gathered group that Jack and the choirboys will be hunters and that he has to have time to think things over.
Ralph further informs the group that he, Jack and Simon will go on an expedition to determine whether they are on an island or not. It is clear from his attitude that Ralph is comfortable in his role and has taken charge. He has made a huge commitment and does, throughout the novel, try his best to do the right things and do them right.
Ralph later displays true leadership when he apologizes to Piggy for having divulged his much-maligned nickname to the other boys:
Ralph, looking with more understanding at Piggy, saw that he was hurt and crushed. He hovered between the two courses of apology or further insult. “Better Piggy than Fatty,” he said at last, with the directness of genuine leadership, “and anyway, I’m sorry if you feel like that. Now go back, Piggy, and take names. That’s your job. So long.”
His apology, followed by an instruction, clearly indicates that Ralph takes responsibility for his actions. In this instance, he expresses remorse and displays leadership—attributes one would expect to find in a mature individual.
After Simon's death, Ralph's reaction later also clearly indicates the fact that he feels partly guilty for his death. He acknowledges his role and tells Piggy:
“That was Simon.”
“You said that before.”
“That was murder.”
The thought is too terrible for Piggy to contemplate, but Ralph makes him understand that even though they were not part of the inner circle during this tragic event, they are just as responsible for Simon's death as the others.
Finally, at the end of the novel, it is Ralph who faces the ship's officer and accedes that he is the "boss." This, by implication, means that he will probably be the one who is questioned most about what transpired on the island, and he seems prepared to accept responsibility.