Sandseter began observing and interviewing children on playgrounds in Norway. In 2011, she published her results in a paper called “Children’s Risky Play From an Evolutionary Perspective: The Anti-Phobic Effects of Thrilling Experiences.” Children, she concluded, have a sensory need to taste danger and excitement; this doesn’t mean that what they do has to actually be dangerous, only that they feel they are taking a great risk. That scares them, but then they overcome the fear. In the paper, Sandseter identifies six kinds of risky play: (1) Exploring heights, or getting the “bird’s perspective,” as she calls it—“high enough to evoke the sensation of fear.” (2) Handling dangerous tools—using sharp scissors or knives, or heavy hammers that at first seem unmanageable but that kids learn to master. (3) Being near dangerous elements—playing near vast bodies of water, or near a fire, so kids are aware that there is danger nearby. (4) Rough-and-tumble play—wrestling, play-fighting—so kids learn to negotiate aggression and cooperation. (5) Speed—cycling or skiing at a pace that feels too fast. (6) Exploring on one’s own.