In the novel Lord of the Flies, why do Ralph and Piggy refuse to paint their faces?

In Chapter 4, Jack decides to paint his face in order to disguise himself and blend in with the environment while he is hunting pigs. The "mask" gives Jack a feeling of liberation, and he is no longer self-conscience. Behind his painted face, Jack feels free to engage in barbaric acts of violence and behave like a savage. In contrast, Ralph and Piggy refuse to paint their faces and act like savages. Both Ralph and Piggy value civility and view Jack and his band of hunters with contempt. They understand the importance of maintaining a structured, civil society and realize that painting their faces will only promote savagery on the island. However, Jack encourages his hunters to follow his lead and mask their faces. Once the hunters paint their faces, they too become more savage and feel free to act violently.