Children constantly test and sample their environment

Laurence Gonzales in Deep Survival discusses adaptation. Page 60.

Once infants begin moving about in the world, they engage in a process of trial and error, by which they find out how much risk they can take to reap a given amount of reward. Every experience adds to the body of knowledge and shapes future behavior. Children constantly test and sample their environment and themselves, taking risks that give big rewards without too much exposure. It's a delicate, and often beautiful, balancing act.