The importance of the setting is that is isolates the boys from any contact with other human society. This allows the boys to develop without any input from adults. The progression from little boys to savages seems to be a natural occurrence. It is something that comes, a the Lord of the Flies says, from inside the boys. I suppose any setting that would isolate the boys from the rest of society could work to promote Golding's message. However, a tropical island is supposed to an idyllic place, free of stress and natural beauty. The contrast between the beautiful place and the development of the boys into savages seems all the more ironic given the contrast between nature and humanity.
It's also interesting that the intrusion of man on the perhaps idyllic island (the plane crash) creates a "scar" on the island. It is almost as though the intrusion of man begins the disintegration of the island, even though it will recover quickly when the men/children leave the island. The boys are not the noble savages of Rousseau ... they come with backgrounds and some "issues" that have clearly been controlled by the social structure. On their own, without the structure, the bad things that are in some of them come to the surface (almost sounds like Freud, except the superego is absent in some of them).
The island becomes a sort of "tabula rasa" where this can be written without the intrusion of the adult/controlling world.
In the novel "Lord of the Flies" careful attention is payed to the way the in depth descriptions of the island was used to create imagery and persuade the readers response. For example on page 14/15, there is much emphasis on the brightness and color of the island. This influences the reader to think that the island is like a tropical paradise full of joy and happiness.
The weather in "Lord of the Flies" plays a major role in representing the attitudes, behavior and mood of the boys throughout the novel. The beach during the day is always described as bright and there is little or no conflict and the ocean is always calm. In the more dense parts of the jungle on the island, it is always described as dark and scary. On the night of Simon's killing, the author describes the night as pitch black and there is great detail of a violent storm raging on the island and the ocean is extremely rough. The weather and ocean symbolize the boy's anger and hatred.
It is evident that plot, setting and characterization in fiction texts all have a significant effect on the reader's response. The reader is made to feel sympathetic towards the characters that are alienated from society, and angry towards those who are mean and violent. The plot has an extremely important role on the reader because it has to maintain their attention and interest. Essentially, plot, setting and characters provide the reader with an image, and their response will be affected depending on how effectively the image is presented.