how does christopher reasoning differ from ours?

The behaviors and demands of adults are mysterious and confusing to most children. To 15-year old Christopher Boone, the narrator in The Curious Incident of the Dog in the Night-Time, it's completely beyond the realm of his understanding. Christopher is an autistic savant and while he's a whiz at math and science, human emotions are particularly complex for him. As the novel opens, he tells us "I know all of the countries of the world and their capital cities, and every prime number up to 7,057." He finds a neighbor's dog, named Wellington, murdered and decides to write about it. With the help of his teacher, Siobhan, he decides to write a book about his attempt to solve this mystery. It's a search for information that will ultimately upset his carefully constructed world.

He doesn't like strange places or people he doesn't know. If people touch him, he will hit them. If his senses become overloaded or his brain too confused, he will curl up in a ball and groan loudly, perhaps for hours at a time. Becoming angry with him just makes it worse. He hates the colors yellow and brown. His world needs order and precision. He will do math problems in his head for hours just to pass the time or distract him from an unpleasant situation.

Because Christopher understands even less of the world than most 15-year olds, the result is that seeing the effects of emotions, lies, and intrigue of the adult world through his eyes lets them hit even more powerfully. Since he sees all this in his non-judgmental perspective and only how they affect the careful order in his world, the flaws of the adults are heightened by their disregard for the effect they have on Christopher while also being tempered by the fact that his autism has placed incredible stresses on all their lives. Christopher is more than just a different medium for seeing the world. In Mark Haddon's capable hands, he quickly becomes all too real, and while he can be incredibly frustrating, he explains his world in a way that makes perfect sense. When events unfold that threaten his carefully maintained world, his quest to solve the problem is as adventurous and dangerous as any literary character. To Christopher, it's something he just must do.