Moving from his story (Christopher does this often in the book), he explains that he has difficulty seeing people’s emotions from their facial expressions. But he can name each country in the world, their capitals, and every prime number up to 7,057. He recalls the first time he met Siobhan, eight years earlier. She drew faces on a piece of paper and asked him what emotions the faces expressed. Christopher could only identify the sad face, which represents how he felt when he found Wellington dead, and the happy face, which shows how he feels when he walks around the neighborhood at three or four in the morning. He could not name the other emotions.