why are childeren used as characters rather then adults by the author?

Golding uses children to make a point about human nature. Many of the children were just grasping the meaning of moral values. The difference between right and wrong (and punishments and rewards) were largely administered by adult figureheads Golding wanted to see what would happen if children were left to develop without being taught how to act. When left to freely develop, is human nature good or evil? The innocence of children is the perfect format to prove his point. British military school kids in particular, turning to savagery brings home Golding's point of the inherent darkness of man's heart.