In Chapter 7, in a stream of consciousness flashback, Ralph daydreams of his home country, England.
Once, following his father from Chatham to Devonport, they had lived in a cottage on the edge of the moors. In the succession of houses that Ralph had known, this one stood out with particular clarity because after that house he had been sent away to school. Mummy had still been with them and Daddy had come home every day. […] When you went to bed there was a bowl of cornflakes with sugar and cream. And the books—they stood on the shelf by the bed, leaning together with always two or three laid flat on top because he had not bothered to put them back properly.
Since the book starts after the boys have crash-landed on the island, and since it proceeds chronologically, flashbacks are the only way the reader can see Ralph's past through his own eyes. Ralph's memories of home, even when they are not as detailed as this one, humanize him and make the reader pity him. We also get small details about Ralph's former life, which is so different from his life on the island as to be shocking. Although we don't know everything about Ralph and his family, we do learn that his father didn't always "come home every day," and that his mother either left or died.
This flashback is written in a different style from the rest of the novel. Note the shifts between second person pronoun "you" and third person pronoun "he." The rest of the book is narrated in the third person, but this slip into the second person destabilizes the memory and makes it dreamlike. In this stream of consciousness moment, rather than recalling a specific event, Ralph lists unconnected associations and images of objects.