A blind woman needs help crossing a busy street in a crowded plaza, but the passers-by all think someone else will help her. Misha decides not to intervene in a bar fight between two large men for fear of getting hurt. Sitting in his car in traffic, Jasper sees two people fighting on a bridge, but no one can see him, so he does not feel the need to help. Shelby sees a man lying on the sidewalk in a big city, but she doesn’t help because ________.