Fear: Fear kills curiosity. When the child's world is chaotic or when he is afraid, he will not like novelty. He will seek the familiar, staying in his comfort zone, unwilling to leave and explore new things. Children impacted by war, natural disasters, family distress, or violence all have their curiosity crushed.
Disapproval: "Don't touch. Don't climb. Don't yell. Don't take that apart. Don't get dirty. Don't. Don't. Don't." Children sense and respond to our fears, biases, and attitudes. If we convey a sense of disgust at the mud on their shoes and the slime on their hands, their discovery of tadpoles will be diminished.
Absence: The presence of a caring, invested adult provides two things essential for optimal exploration: 1) a sense of safety from which to set out to discover new things and 2) the capacity to share the discovery and, thereby, get the pleasure and reinforcement from that discovery.
If we let them, children can reintroduce us to the world. When we truly allow a child to share his discoveries with us, we experience the joys of rediscovery—and in doing so, learn ourselves.